AQ-2023-003-RULE331 REPORT TO THE BOARD OF SUPERVISORS.PDF

Air Quality Department 
301 W. Jefferson St., Suite 410 
Phoenix, Arizona 85003 
P: 602-506-6010 
E: AQMail@maricopa.gov 
 
Executive Summary of the Report to the Board of Supervisors 
Prepared by Maricopa County Air Quality Department 
Board Hearing Date: 
September 25, 2024 
Case Number/Title:  
AQ-2023-003-Rule 331 (Solvent Cleaning) 
Agenda Item:  
(Pending) 
Supervisor Districts: 
All Districts 
The Maricopa County Air Quality Department (MCAQD) complied with all statutory and county 
policies throughout this rulemaking process. Per the Enhanced Regulatory Outreach Program 
(EROP) Policy: “In addition to the required staff report, an executive summary of the report 
including an overview of stakeholder input and staff responses will be provided to the Board 
of Supervisors at least one week prior to any Board of Supervisors’ public hearing.” 
Overview of the Report to the Board of Supervisors: 
MCAQD is proposing to revise Rule 331 (Solvent Cleaning) to remove a reasonably available 
control technology (RACT) deficiency identified by the U.S. Environmental Protection Agency 
(EPA) so Rule 331 can be approved into the Arizona State Implementation Plan (SIP) as 
meeting RACT.  
On November 7, 2022, the EPA reclassified portions of Maricopa County as a moderate 
nonattainment area with respect to the 2015 8-hour ozone National Ambient Air Quality 
Standard. Sections 182(b)(2) and (f) of the Clean Air Act (CAA) require jurisdictions that are 
classified as “moderate” or higher nonattainment for ozone to implement RACT for all 
sources subject to a Control Techniques Guideline (CTG) as well as for all non-CTG major 
sources of volatile organic compounds (VOCs) or nitrogen oxides (NOx). 
In response to the reclassification, MCAQD determined Rule 331 does not meet RACT. 
Although Rule 331 is considered as stringent or more stringent than the two CTG source 
categories it is associated with, it contains an exemption that the EPA has determined is a 
deficiency. Rule 331 exempts all operations regulated by National Emission Standards for 
Halogenated Solvent Cleaning (40 CFR 63, Subpart T). This exemption precludes Rule 331

from satisfying the CAA Section 182(b)(2) RACT requirement. Section 182(b)(2) requires that 
RACT be implemented through SIP-approved rules and reliance on rules outside the SIP such 
as a National Emission Standard for Hazardous Air Pollutants (NESHAP) for the 
implementation of RACT is insufficient. NESHAPs are separate obligations under the CAA and 
may be less stringent than RACT if the NESHAP is outdated. Therefore, removing the NESHAP 
exemption will ensure Rule 331 meets RACT. 
In addition, MCAQD is proposing other revisions to the rule including lowering the VOC 
content limit in the definition of Low-VOC Cleaner from 50 grams of VOC per liter to 25 grams 
of VOC per liter as well as restructuring the rule for clarity purposes. MCAQD plans to replace 
SIP Rule 34, Sections F-K (Organic Solvents – Volatile Organic Compounds (VOC)) and current 
SIP Rule 331 with the revised rule to update the SIP and clarify regulatory requirements. 
Overview of Stakeholder Input and Staff Responses: 
MCAQD received written feedback from three (3) stakeholders. One (1) stakeholder 
expressed opposition and two (2) stakeholders expressed neither support nor opposition to 
the rulemaking. MCAQD evaluated the comments and drafted responses. The stakeholders’ 
comments and the MCAQD’s responses are included under Section 9 of the attached Draft 
Notice of Final Rulemaking. Copies of the stakeholders’ written feedback and comments are 
attached to this report.
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Maricopa County 
Air Quality Department 
Planning and Analysis Division 
Report to the 
Board of 
Supervisors 
Rule 331 (Solvent 
Cleaning)
September 2024

Board of Health Meeting Date: 
July 22, 2024 
Board Hearing Date: 
September 25, 2024 
Case Number/Title:  
AQ-2023-003-Rule 331 (Solvent Cleaning) 
Agenda Item: 
(Pending) 
Supervisor Districts: 
All Districts 
Applicant:  
Staff 
Request: 
Approve revision of Maricopa County Air Pollution Control 
Regulations, Rule 331 (Solvent Cleaning) and approve 
submission of the revised rule as a revision to the Arizona 
State Implementation Plan (SIP). 
Rule 331 establishes limits for emissions of volatile organic 
compounds (VOCs) from solvent cleaning operations. Rule 
331 applies to operations using VOC-containing solvents to 
remove impurities from exterior or interior surfaces. 
The Maricopa County Air Quality Department (MCAQD) is 
proposing to revise Rule 331 to remove a reasonably 
available control technology (RACT) deficiency identified by 
the U.S. Environmental Protection Agency (EPA) so Rule 331 
can be approved into the Arizona SIP as meeting RACT. 
On November 7, 2022, the EPA reclassified portions of 
Maricopa County as a moderate nonattainment area with 
respect to the 2015 8-hour ozone National Ambient Air 
Quality Standard. Sections 182(b)(2) and (f) of the Clean Air 
Act (CAA) require jurisdictions that are classified as 
“moderate” or higher nonattainment for ozone to implement 
RACT for all sources subject to a Control Techniques 
Guideline (CTG) as well as for all non-CTG major sources of 
VOCs or nitrogen oxides (NOx). 
In response to the reclassification, MCAQD determined Rule 
331 does not meet RACT. Although Rule 331 is considered 
as stringent or more stringent than the two CTG source 
categories it is associated with, it contains an exemption 
that the EPA has determined is a deficiency. Rule 331 
exempts all operations regulated by National Emission 
Standards for Halogenated Solvent Cleaning (40 CFR 63, 
Subpart T). This exemption precludes Rule 331 from 
satisfying the CAA Section 182(b)(2) RACT requirement. 
Section 182(b)(2) requires that RACT be implemented 
through SIP-approved rules and reliance on rules outside the 
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SIP such as a National Emission Standard for Hazardous Air 
Pollutants (NESHAP) for the implementation of RACT is 
insufficient. NESHAPs are separate obligations under the 
CAA and may be less stringent than RACT if the NESHAP is 
outdated. Therefore, removing the NESHAP exemption will 
ensure Rule 331 meets RACT. 
In addition, MCAQD is proposing other revisions to the rule 
including lowering the VOC content limit in the definition of 
Low-VOC Cleaner from 50 grams of VOC per liter to 25 
grams of VOC per liter as well as restructuring the rule for 
clarity purposes. MCAQD plans to replace SIP Rule 34, 
Sections F-K (Organic Solvents – Volatile Organic 
Compounds (VOC)) and current SIP Rule 331 with the 
revised rule to update the SIP and clarify regulatory 
requirements. 
Support/Opposition: 
MCAQD received written feedback from three (3) 
stakeholders. One (1) stakeholder expressed opposition and 
two (2) stakeholders expressed neither support nor 
opposition to the rulemaking. MCAQD evaluated the 
comments and drafted responses. The stakeholders’ 
comments and the MCAQD’s responses are included under 
Section 9 of the attached Draft Notice of Final Rulemaking. 
Copies of the stakeholders’ written feedback and comments 
are attached to this report. 
Staff 
Recommendation: 
Approve 
Board of Health 
Recommendation: 
Approve 
Additional Comments: 
This regulatory change is following the Enhanced Regulatory 
Outreach Program (EROP) Policy and workflow process. The 
County Manager briefed the Board of Supervisors regarding 
this rulemaking in February 2023. Stakeholder Workshops 
were held on June 20, 2023, and December 13, 2023.  
The Board of Health approved initiation of regulatory change 
on August 28, 2023, and a Notice of Proposed Rulemaking 
was posted on the EROP website on June 5, 2024. On July 
22, 2024, the Board of Health made a recommendation to 
the Board of Supervisors to approve the revisions to Rule 
331. 
A newspaper notice of the Board of Supervisors public 
hearing will be published in the Arizona Business Gazette on 
August 22, 2024, and August 29, 2024. This regulatory 
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change will take effect immediately upon approval by the 
Board of Supervisors. 
Presented By: 
Philip A. McNeely, R.G., Director 
Prepared By: 
Planning and Analysis Division 
Attachments: 
Preamble required by Arizona Revised Statutes (A.R.S.) § 
49-471.07 (See the Draft Notice of Final Rulemaking)
Summary of the proposed regulatory change (See Item 4 
of the Draft Notice of Final Rulemaking) 
Analysis of input received during the process and how that 
input was responded to (See Item 9 of the Draft Notice of 
Final Rulemaking)
Language of proposed regulatory change or amendment 
(See the Draft Notice of Final Rulemaking) 
Strikethrough/underline of Draft Rule 331 
Clean version of Draft Rule 331 
Minutes from Board of Health meeting - August 28, 2023 
Minutes from Board of Health meeting - July 22, 2024 Pending 
Copies of all written and electronic Stakeholder input 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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Maricopa County 
Air Quality Department 
Planning and Analysis Division 
Draft Notice of 
Final 
Rulemaking 
Rule 331 (Solvent 
Cleaning) 
September 2024

Draft Notice of Final Rulemaking 
Maricopa County Air Pollution Control Regulations 
Regulation III – Control of Air Contaminants 
Rule 331 (Solvent Cleaning) 
The Maricopa County Air Quality Department (MCAQD) is proposing to amend Rule 331 (Solvent 
Cleaning). The Control Officer is posting this Draft Notice of Final Rulemaking on the Maricopa 
County Enhanced Regulatory Outreach Program (EROP) website as part of the Report to the 
Board of Supervisors, in accordance with the Maricopa County EROP Policy. This notice includes 
the preamble, as prescribed in Arizona Revised Statutes (A.R.S.) § 49-471.05, and the full text of 
the rule, including the intended actions to make new sections or amend, repeal, or renumber the 
sections of the rule. This notice also includes a list of all previous notices posted on the 
Maricopa County EROP website addressing the proposed rule and the concise explanatory 
statement prescribed in A.R.S. § 49-471.07(B). 
Preamble 
1.
Statutory authority for the rulemaking (A.R.S. § 49-471.05(1)):
A.R.S. §§ 49-112, 49-474, 49-479 and 49-480
2.
Name and address of department personnel with whom persons may communicate
regarding the rulemaking (A.R.S. § 49-471.05(2)):
Name: 
Hannah Luke or Kimberly Butler 
Maricopa County Air Quality Department 
Planning and Analysis Division 
Address: 
301 W. Jefferson St., Suite 410 
Phoenix, AZ 85003 
Telephone: 
602-506-6010
Fax: 
602-506-6179
Email: 
AQPlanning@maricopa.gov 
Online: 
Submit a Comment 
3.
Rulemaking process (A.R.S. § 49-471.05(3)):
This rulemaking is following procedures identified in state statutes and the Maricopa
County EROP Policy.
County Manager Briefing: 
February 1, 2023
Return to list of attachments
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First Stakeholder Workshop: 
June 20, 2023 
Second Stakeholder Workshop: 
December 13, 2023 
Board of Health Meeting to Initiate Regulatory 
Change: 
August 28, 2023 
Notice of Proposed Rulemaking: 
June 5, 2024 
Board of Health Meeting to Recommend Approval 
to the Board of Supervisors:  
July 22, 2024 
Board of Supervisors Formal Meeting to Set 
the Public Hearing: 
August 21, 2024 
Board of Supervisors Public Hearing: 
September 25, 2024 
4.
Explanation of the rule, including the control officer's reasons for initiating the
rulemaking (A.R.S. § 49-471.05(4)):
The purpose of Rule 331 (Solvent Cleaning) is to limit volatile organic compound (VOC)
emissions from solvent cleaning operations. The last significant revision to the rule
occurred in 2004. MCAQD is proposing to revise Rule 331 to remove a reasonably
available control technology (RACT) deficiency identified by the U.S. Environmental
Protection Agency (EPA) so Rule 331 can be approved into the Arizona State
Implementation Plan (SIP) as meeting RACT.
On November 7, 2022, the EPA reclassified portions of Maricopa County as a moderate
nonattainment area with respect to the 2015 8-hour ozone National Ambient Air Quality
Standard (NAAQS). Sections 182(b)(2) and (f) of the Clean Air Act (CAA) require
jurisdictions that are classified as “moderate” or higher nonattainment for ozone to
implement RACT for all sources subject to a Control Techniques Guideline (CTG) as well
as for all non-CTG major sources of VOCs or nitrogen oxides (NOx).
In response to the reclassification, the MCAQD reviewed all rules associated with a CTG
source category to determine if the rules meet RACT. During the analysis, MCAQD
determined Rule 331 (Solvent Cleaning) does not meet RACT. Although Rule 331 is
considered as stringent or more stringent than the two CTG source categories it is
associated with, it contains an exemption that the EPA has determined is a deficiency.
Rule 331 exempts all operations regulated by National Emission Standards for
Halogenated Solvent Cleaning (40 CFR 63, Subpart T). This exemption precludes Rule
331 from satisfying the CAA section 182(b)(2) RACT requirement. Section 182(b)(2)
requires that RACT be implemented through SIP-approved rules and reliance on rules
outside the SIP such as a National Emission Standard for Hazardous Air Pollutants
(NESHAP) for the implementation of RACT is insufficient. NESHAPs are separate
obligations under the CAA and may be less stringent than RACT if the NESHAP is
outdated. Therefore, removing the NESHAP exemption will ensure Rule 331 meets
RACT.
Return to list of attachments
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In addition, MCAQD is proposing other revisions to the rule including lowering the VOC 
content limit in the definition of Low-VOC Cleaner from 50 grams of VOC per liter to 25 
grams of VOC per liter as well as restructuring the rule for clarity purposes. MCAQD 
plans to replace SIP Rule 34, Sections F-K (Organic Solvents – Volatile Organic 
Compounds (VOC)) and current SIP Rule 331 with the revised rule to update the SIP and 
clarify regulatory requirements.  
5.
Studies relied on in the control officer's evaluation of or justification for the rule and
where the public may obtain or review the studies, all data underlying the studies, any
analysis of the studies and other supporting material (A.R.S. § 49-471.05(5)).
No studies were relied on in the control officer’s evaluation of the rule.
6.
An economic, small business and consumer impact statement (A.R.S. § 49-
471.05(6)):
The following discussion addresses each of the elements required for an economic,
small business and consumer impact statement, as prescribed by A.R.S. §§ 41-1055,
subsections A, B and C, and 41-1035:
An identification of the proposed rulemaking, including all of the following (A.R.S. §
41-1055(A)(1)):
The purpose of this rulemaking is twofold. First, this rulemaking will revise Rule 331 to 
remove a RACT deficiency identified by the EPA in order to ensure the rule can be 
approved into the SIP as meeting RACT. Second, MCAQD plans to replace SIP Rule 34, 
Sections F-K with the revised rule in order to eliminate the regulatory gap where sources 
are subject to different federal and county rules for the same activity. 
(a) The conduct and its frequency of occurrence that the rule is designed to change
(A.R.S. § 41-1055(A)(1)(a)).
MCAQD is proposing to revise Rule 331 to remove a deficiency identified by the EPA
in order to have the rule approved into the SIP as meeting RACT while also replacing
SIP Rule 34, Sections F-K.
(b) The harm resulting from the conduct the rule is designed to change and the
likelihood it will continue to occur if the rule is not changed (A.R.S. § 41-
1055(A)(1)(b)).
Due to Maricopa County being reclassified as a moderate nonattainment area with
respect to the 2015 8-hour ozone NAAQS, MCAQD reviewed all rules associated with
a CTG source category to determine if the rules meet RACT. During the analysis,
MCAQD determined Rule 331 does not meet RACT.
In order to comply with Sections 182(b)(2) and (f) of the CAA, MCAQD is required to
revise Rule 331 to ensure the rule implements RACT. Failure to do so could result in
sanctions and imposition of a Federal Implementation Plan (FIP) under the CAA
which could adversely affect Maricopa County.
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(c) The estimated change in frequency of the targeted conduct expected from the rule
change (A.R.S. § 41-1055(A)(1)(c)).
MCAQD is proposing to revise Rule 331 to remove a deficiency identified by the EPA
in order to have the rule approved into the SIP as meeting RACT while also replacing
SIP Rule 34, Sections F-K.
A brief summary of the information included in the economic, small business and 
consumer impact statement (A.R.S. § 41-1055(A)(2)). 
The economic, small business and consumer impact statement addresses each of the 
elements required for an economic, small business and consumer impact statement, as 
prescribed by A.R.S. §§ 41-1055, subsections A, B, C, and 41-1035. 
Name and address of agency employees who may be contacted to submit or request 
additional data on the information included in the economic, small business and 
consumer impact statement (A.R.S. § 41-1055(A)(3)). 
Name: 
Hannah Luke or Kimberly Butler 
Maricopa County Air Quality Department 
Planning and Analysis Division 
Address: 
301 W. Jefferson St., Suite 410 
Phoenix, AZ 85003 
Telephone: 
602-506-6010
Fax: 
602-506-6179
Email: 
AQPlanning@maricopa.gov 
Online: 
Submit a Comment 
An identification of the persons who will be directly affected by, bear the costs of or 
directly benefit from the proposed rulemaking (A.R.S. § 41-1055(B)(2)). 
This rulemaking will directly affect facilities in Maricopa County that use VOC-
containing solvents to remove impurities from exterior or interior surfaces and are not 
exempt as detailed in Section 104 of the draft rule. Partial exemptions apply to certain 
operations and application methods.  
A cost benefit analysis of the following: 
(a) The probable costs and benefits to the implementing agency and other agencies
directly affected by the implementation and enforcement of the proposed
rulemaking (A.R.S. § 41-1055(B)(3)(a)).
This rulemaking should not impose any new costs on MCAQD or on any other
agencies affected by the proposed rulemaking.
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(b) The probable costs and benefits to a political subdivision of this state directly
affected by the implementation and enforcement of the proposed rulemaking
(A.R.S. § 41-1055(B)(3)(b)).
This rulemaking should not impose any new costs on political subdivisions of this
state affected by the proposed rulemaking.
(c) The probable costs and benefits to businesses directly affected by the proposed
rulemaking, including any anticipated effect on the revenues or payroll
expenditures of employers who are subject to the proposed rulemaking (A.R.S. §
41-1055(B)(3)(c)).
For businesses currently using a low-VOC cleaner of 50 g/L, compliance with the 
revised Rule 331 may involve some additional costs related to purchasing Rule 331-
compliant low-VOC cleaner of 25 g/L. For businesses that are complying with one of 
the solvent specification requirements in Section 302.1 or using solvent that meets 
the new 25 g/L VOC content limit, there would be no additional cost.  
A general description of the probable impact on private and public employment in 
businesses, agencies and political subdivisions of this state directly affected by the 
proposed rulemaking (A.R.S. § 41-1055(B)(4)). 
This rulemaking should have no impact on private or public employment in businesses, 
agencies, and political subdivisions of this state. 
A statement of the probable impact of the proposed rulemaking on small businesses. 
The statement shall include: 
(a) An identification of the small businesses subject to the proposed rulemaking
(A.R.S. § 41-1055(B)(5)(a)).
Small businesses subject to this rulemaking are those facilities in Maricopa County
that use VOC-containing solvents which do not fall under the exemptions in Section
104 of the draft rule included in this notice.
(b) The administrative and other costs required for compliance with the proposed
rulemaking (A.R.S. § 41-1055(B)(5)(b)).
For businesses currently using a low-VOC cleaner of 50 g/L, compliance with the
revised Rule 331 may involve some additional costs related to purchasing Rule 331-
compliant low-VOC cleaner of 25 g/L. For businesses that are complying with one of
the solvent specification requirements in Section 302.1 or using solvent that meets
the new 25 g/L VOC content limit, there would be no additional cost.
(c) A description of the methods that the agency may use to reduce the impact on
small businesses (A.R.S. § 41-1055(B)(5)(c)).
i.
Establish less stringent compliance or reporting requirements in the rule for
small businesses (A.R.S. § 41-1035(1)).
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Most of the proposed revisions are intended to enhance or clarify Rule 331 and 
should not impose any significant new compliance requirements on small 
businesses. Proposed revisions to Rule 331 do not establish any significant new 
reporting requirements for small businesses.  
The rulemaking does propose lowering the VOC content limit for low-VOC 
cleaners from 50 g/L to 25 g/L. Outreach with affected stakeholders has been 
conducted, including two stakeholder workshops, citizen comment opportunities, 
and the proposed revisions were presented at two Board of Health public 
meetings on August 28, 2023 and July 22, 2024. During the rulemaking process, 
MCAQD has received one citizen comment related to the low-VOC cleaner 
limitation and determined that there would be no economic impact on the 
stakeholder who submitted the comment. There have been no further citizen 
comments notifying MCAQD that there would be any significant impact on small 
businesses due to the proposed revisions.  
ii. Establish less stringent schedules or deadlines in the rule for compliance or
reporting requirements for small businesses (A.R.S. § 41-1035(2)).
This rulemaking does not impose any significant new compliance schedule
requirements on small businesses and does not establish any significant new
reporting requirements for small businesses.
iii. Consolidate or simplify the rule's compliance or reporting requirements for
small businesses (A.R.S. § 41-1035(3)).
This rulemaking does not impose any significant new compliance requirements
on small businesses and does not establish any significant new reporting
requirements for small businesses.
iv. Establish performance standards for small businesses to replace design or
operational standards in the rule (A.R.S. § 41-1035(4)).
This rulemaking does not impose any significant new design or operational
standards on small businesses.
v. Exempt small businesses from any or all requirements of the rule (A.R.S. § 41-
1035(5)).
This rulemaking contains partial and full exemptions as outlined in Sections 103
and 104 of the draft rule.
(d) The probable cost and benefit to private persons and consumers who are directly
affected by the proposed rulemaking (A.R.S. § 41-1055(B)(5)(d)).
This rulemaking should not result in any significant costs for private persons and
consumers.
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A statement of the probable effect on state revenues (A.R.S. § 41-1055(B)(6)). 
The rulemaking will not impose increased monetary or regulatory costs on other state 
agencies, political subdivisions of this state, persons, or individuals so regulated. 
Without costs to pass through to customers, there is no projected change in consumer 
purchase patterns and, thus, no impact on state revenues from sales taxes. 
A description of any less intrusive or less costly alternative methods of achieving the 
purpose of the proposed rulemaking, including the monetizing of the costs and 
benefits for each option and providing the rationale for not using nonselected 
alternatives (A.R.S. § 41-1055(B)(7)). 
The purpose of this rulemaking is to revise Rule 331 to remove a deficiency identified by 
the EPA in order to have the rule approved into the SIP as meeting RACT while also 
replacing SIP Rule 34, Sections F-K. Failure to remove the deficiency could result in 
sanctions and imposition of a FIP under the CAA which could adversely affect Maricopa 
County.  
A description of any data on which a rule is based with a detailed explanation of how 
the data was obtained and why the data is acceptable data (A.R.S. § 41-1055(B)(8)). 
Not applicable. 
7.
The proposed effective date of the rule (A.R.S. § 49-471.05(7)):
The proposed effective date of this rulemaking is September 25, 2024.
8.
Such other matters as are prescribed by statute and that are applicable to the county
or to any specific rule or class of rules (A.R.S. § 49-471.05(8)):
Under A.R.S. § 49-479(C), a county may not adopt a rule or ordinance that is more
stringent than the rules adopted by the Director of the Arizona Department of
Environmental Quality (ADEQ) for similar sources unless it demonstrates compliance
with the applicable requirements of A.R.S. §49-112.
§ 49-112 County regulation; standards
§ 49-112(A)
When authorized by law, a county may adopt a rule, ordinance or regulation that is more 
stringent than or in addition to a provision of this title or rule adopted by the director or 
any board or commission authorized to adopt rules pursuant to this title if all of the 
following requirements are met: 
1. The rule, ordinance or regulation is necessary to address a peculiar local condition.
2. There is credible evidence that the rule, ordinance or regulation is either;
(a) Necessary to prevent a significant threat to public health or the environment that
results from a peculiar local condition and is technically and economically
feasible.
(b) Required under a federal statute or regulation, or authorized pursuant to an
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intergovernmental agreement with the federal government to enforce federal 
statutes or regulations if the county rule, ordinance or regulation is equivalent to 
federal statutes or regulation. 
3. Any fee or tax adopted under the rule, ordinance or regulation does not exceed the
reasonable costs of the county to issue and administer the permit or plan approval
program.
§ 49-112(B)
When authorized by law, a county may adopt rules, ordinances or regulations in lieu of a 
state program that are as stringent as a provision of this title or rule adopted by the 
director or any board or commission authorized to adopt rules pursuant to this title if 
the county demonstrates that the cost of obtaining permits or other approvals from the 
county will approximately equal or be less than the fee or cost of obtaining similar 
permits or approvals under this title or any rule adopted pursuant to this title. If the state 
has not adopted a fee or tax for similar permits or approvals, the county may adopt a 
fee when authorized by law in the rule, ordinance or regulation that does not exceed the 
reasonable costs of the county to issue and administer that permit or plan approval 
program. 
MCAQD is in compliance with A.R.S. §§ 49-112(A) and (B). Rule 331 meets A.R.S. § 49-
112(A)(1) by demonstrating that the rule is necessary to address a peculiar local 
condition, in that Maricopa County fails to meet the 2015 8-hour NAAQS for ozone. Rule 
331 meets the requirements of A.R.S.§ 49-112(A)(2)(b), in that Maricopa County is 
required by federal law to revise existing rules to address RACT for the solvent cleaning 
industry. As there is no new fee or tax associated with this proposed rulemaking, the 
MCAQD also affirms that Rule 331 meets the requirements of A.R.S. § 49-112 (A)(3) 
and A.R.S § 49-112 (B). 
9.
List of all previous notices posted to the Maricopa County EROP website addressing
the proposed rule and a concise explanatory statement, as prescribed by A.R.S. § 49-
471.07(B):
(a) List of all previous notices posted to the Maricopa County EROP website
addressing the proposed rule:
Notice 
 
Date of Posting 
Briefing Notification to County Manager: 
March 9, 2023  
Notice of First Stakeholder Workshop: 
June 6, 2023  
Notice of First Board of Health Meeting: 
July 7, 2023  
Notice of Second Stakeholder Workshop: 
November 29, 2023 
Notice of Proposed Rulemaking: 
June 5, 2024  
Notice of Second Board of Health Meeting: 
July 8, 2024  
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(b) The following discussion addresses each of the elements required for a
concise explanatory statement, as prescribed by A.R.S. § 49-471.07(B):
i. A description of any change between the proposed rule or ordinance, the
final rule or ordinance or notice of final supplemental rule or ordinance.
The following changes were made after the Notice of Proposed Rulemaking
was published on June 5, 2024:
1.
Revised the partial exemption for wipe cleaning in Section 103.1. The
section now reads as follows:
“Wipe cleaning is only subject to Sections 301.1 and 501 of this rule.”
2.
Removed the categorical exemption previously listed under Section
104.1(e) regarding industries and cleaning operations that are not
regulated by Rule 331 and adjusted formatting under Section 104.
3.
Added the phrase “using the County’s public records request process” to
Section 501.3. This section now reads as follows:
“Records shall be made available to the Control Officer upon request by
members of the public using the County’s public records request process.”
4.
Added subsection 501.4 under Section 501 and adjusted the numbering in
Section 501 as a result of the added subsection. This subsection reads as
follows:
“Records shall be kept on site at all times in a consistent and complete
manner.”
5.
Added the phrase “smaller of either the length or” to Section 214. This
section now reads as follows:
“The freeboard height divided by the smaller of either the length or width
of the solvent cleaning machine.”
ii. A summary of the comments and arguments for and against the notice and
the county’s response to the comments and arguments.
A summary of the comments and arguments for and against the notice and
the county’s response to the comments and arguments.
The following discussion evaluates the arguments for and against the rule and
includes responses to comments received on the proposed rule or the
preamble in the Notice of Proposed Rulemaking. MCAQD received written
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comments from three stakeholders. All of the comments were reviewed and 
evaluated by MCAQD. 
Comment #1:  
Below please find NXP’s input regarding proposed revisions to Rule 330 
(Volatile Organic Compounds (VOCs)) and Rule 331 (Solvent Cleaning). 
We suggest the following modifications to the draft rules 330 and 331 to 
ensure consistency between these two rules as well as Rule 338 
(Semiconductor Manufacturing): 
Modify section 502.3 of rule 331 to match section 502.3 in rule 330 and 338: 
For each day or period the O&M Plan requires maintenance, the owner or 
operator shall make a permanent record of the maintenance actions taken 
within 24 hours 3 business days of the maintenance completion. 
Response #1:  
MCAQD evaluated your comment and agrees with the suggestion. The 
proposed language has been incorporated into the draft rule.  
Comment #2:  
I apologize in that I missed the initial outreach meeting on this rulemaking 
action. My comment pertains to the change in the definition of low VOC from 
50 grams/liter to 25 grams/liter. This is quite a dramatic change to an already 
low VOC content, and I was not able to find any technical or economic analysis 
of this change. Unless this change can be shown to be both economically and 
technically feasible, it should not be made. 
Please provide the justification for this change showing that it is reasonable 
and there are products on the market that can accomplish the cleaning 
objectives at an affordable cost. 
Response #2:  
MCAQD evaluated your comment and will maintain the proposed VOC content 
of 25 grams/liter in the definition for “Low-VOC Cleaner”. Research conducted 
showed other districts classified as moderate nonattainment areas for the 8-
hour ozone National Ambient Air Quality Standards have incorporated the 25 
g/L VOC content standard in their solvent cleaning rules. Examples include 
Yolo-Solano Air Quality Management District – Rule 2.31 (Solvent Cleaning, 
revised July 14, 2021) and the State of New York, Department of 
Environmental Conservation – 6 CRR-NY 226-1.4 (Solvent Cleaning Processes 
and Industrial Cleaning Solvents, revised November 1, 2019).  
Furthermore, the 25 g/L VOC content standard has been implemented in 
solvent cleaning rules in the following districts:  
•
San Joaquin Valley Air Pollution Control District - Rule 4663 (Solvent
Cleaning, revised September 20, 2007)
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•
South Coast Air Quality Management District - Rule 1122 (Solvent
Degreasers, revised May 1, 2009) and Rule 1171 (Solvent Cleaning
Operations, revised May 1, 2009)
•
Ventura County Air Pollution Control District - Rule 74.6 (Surface
Cleaning and Degreasing, revised November 10, 2020)
•
San Diego Air Pollution Control District - Rule 67.6.1 (Cold Solvent
Cleaning and Stripping Operations, revised February 10, 2021)
•
Antelope Valley Air Quality Management District - Rule 1171 (Solvent
Cleaning Operations, revised August 21, 2018)
•
Sacramento Air Quality Management District - Rule 466 (Solvent
Cleaning, revised October 28, 2010)
The fact that many air quality districts, including districts nearby, have already 
implemented the lower standard indicates the availability of the products that 
comply with the proposed limit.  
In addition, MCAQD has received only one comment regarding the proposed 
revision (Comment #2) and through discussion with the commenter it was 
determined the commenter could comply with the Rule 331 solvent 
specification requirements through an alternative compliance option in Rule 
331, using a conforming solvent. A conforming solvent is a cleaning-solvent 
having a total VOC vapor pressure at 68° F (20° C) not exceeding 1.0 millimeter 
of mercury column (mm Hg).  
MCAQD conducted a survey regarding solvent usage among permitted 
facilities within Maricopa County from September 2021 through August 2022. 
Information was obtained during routine inspections for permitted facilities 
that conduct solvent cleaning operations. Results reflected the majority of the 
facilities conducting non-vapor cleaning operations (operations subject to the 
solvent specification requirements) used a conforming solvent to comply with 
the solvent specification requirements in Rule 331. 
Comment #3:  
In general, this rule could be made clearer and explicitly state the requirements 
for cleaning machines that can be done to avoid an ECS. In CH solvent 
“cleaning machines” are impacted as they don’t have a "remote reservoir" or 
non-remote internal reservoir". Cleaning machines use IPA solvent with a 
volume > than 1 square foot and > 1 gallon with VP > than 1mm Hg. 
Attempting to route “cleaning machine” emissions to an ECS is not practical 
as these sources if connected to a ECS the result would be a very high flow, 
dilute exhaust stream driving significant increases in NOx that would likely 
exceed current Air Permit Limits. 
Response #3:  
During the Rule 331 and Rule 338 (Semiconductor Manufacturing) rulemaking 
processes, solvent cleaning provisions related to semiconductor 
manufacturing activities were proposed to be removed from Rule 338 and 
relocated to Rule 331. Comment numbers 3 through 6 were all received from 
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stakeholders in the semiconductor industry when solvent cleaning provisions 
related to semiconductor manufacturing were proposed to be relocated to 
Rule 331. After working with EPA, affected stakeholders, and internal staff, it 
was decided to keep solvent cleaning provisions related to semiconductor 
manufacturing in Rule 338. Based on this information, there will be no 
revisions to Rule 331 related to semiconductor manufacturing operations.  
Comment #4:  
Intel utilizes a number of “batch” cleaning machines, some of which use non-
conforming solvents and are not small enough to be considered small 
cleaners. However, it is our understanding that rule 331 would not require such 
machines to be connected to an ECS as section 302.c(4) states that a non-
conforming solvent may be used if one of conditions “a” through “c” are met. 
Part “c” of this section exempts certain SIC codes described in section 103.3 
including electronics manufacturing, which is the category Intel fits in. Based 
on this it is our conclusion that batch cleaning systems would not be required 
to be connected to an ECS. We would appreciate your thoughts on if we’re 
interpreting this correctly.  
Response #4:  
See Response #3. 
Comment #5:  
The Proposed Rule 331 could appear to require that some in-line cleaning 
systems be connected to an ECS as section 302.3 does not include the section 
103.3 SIC Code exemption for in-line cleaning machines. Our review of the 
semiconductor solvent cleaning equipment that use IPA and EtOH and 
covered by this Rule has identified requirements to connect to an ECS. Our 
estimates show that this could result in an additional 5000 cfm of exhaust 
connected to an ECS, which could potentially result in an additional ~2200 lbs. 
of NOx per year. Intel’s current estimates of VOCs from these tools is < 
~10,000 lbs./year, so this rule would result in generating 2200 lbs. NOx to 
remove this quantity of VOCs. 
Response #5:  
See Response #3. 
Comment #6:  
Suggested clarifications to the Proposed New Rule 331, language for Partial 
Exemptions in 103.3 
•
The SICs Codes for Industry Group 367 (Semiconductor Operations) are
not referenced in 103.3.  Both Intel Chandler Campus and Ocotillo
Campus are both SIC Code 3674, and we can assume that NXP and
TSMC are also 3674. Can you add SIC Code 3674 to 103.3 to include
these Semiconductor Operations that are most significant in Maricopa
County and as discussed meeting the intent of the exemption?
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•
Also, in support of adding SIC Code 3674, the SIC Codes listed do not
correspond with the 103.4 ISO cleanroom requirements. In other words,
the SIC Codes referenced in 103.3 do need the cleanrooms referenced
in 103.4.
•
Considering this current language above, in the 3/19 second letter
where we incorrectly stated that our R&D Batch cleaning was exempt
due to 331 103.3 (i.e., SIC Code 3674 was missing), whereas we should
have referenced 103.4 (i.e., ISO).
•
Note, in 302.2c.(4) Non-Conforming Solvent references 103.3 (SIC)
which does not include Intel Semiconductors in the exemption and
instead could replace 103.3 with 103.4 or add both 103.3 and 103.4?
•
In conclusion adding 3674 SIC Code to 103.3 may clarify the Partial
Exemptions in Proposed New Rule 331, 103.
Response #6:  
See Response #3. 
Exact Wording of the Rule 
MARICOPA COUNTY AIR POLLUTION CONTROL REGULATIONS 
REGULATION III – CONTROL OF AIR CONTAMINANTS 
RULE 331 (SOLVENT CLEANING) 
INDEX 
SECTION 100 – GENERAL 
101 
PURPOSE 
102 
APPLICABILITY 
308 
103 
PARTIAL EXEMPTIONS 
308 
104 
TOTAL CATEGORICAL EXEMPTIONS 
SECTION 200 – DEFINITIONS 
201 
AGITATION, AGITATED 
202 
BATCH CLEANING MACHINE 
203 
BLASTING/MISTING WITH SOLVENT 
204 
CABINET STYLE CLEANING MACHINES 
205 
CARRY-OUT 
206 
CLEANING-SOLVENT 
Return to list of attachments
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207 
CONFORMING SOLVENT 
208 
DEGREASER 
208 
DIP TANK 
209 
DRY SOLID 
210 
EMISSION CONTROL SYSTEM (ECS) 
211 
FILTRATION DEVICE 
211 
212 
FLUSHING WITH SOLVENT 
212 
213 
FREEBOARD HEIGHT 
213 
214 
FREEBOARD RATIO 
215 
FULLY SUBMERGED 
214 
216 
HEATED SOLVENT 
215 
217 
IMPERVIOUS 
216 
218 
IN-LINE CLEANING MACHINE (CONTINUOUS CLEANING MACHINE) 
217 
219 
JANITORIAL CLEANING 
218 
220 
LEAK 
219 
221 
LOW-VOC CLEANER 
220 
222 
MAKE-UP SOLVENT 
221 
MATERIAL VOC CONTENT 
222 
223 
NON-CONFORMING SOLVENT 
224 
NON-VAPOR CLEANING MACHINE 
223 
ORGANIC COMPOUND 
225 
PARTS PER MILLION BY VOLUME DRY (PPMVD) 
224 
226 
REFRIGERATED FREEBOARD CHILLER 
225 
227 
REMOTE RESERVOIR CLEANING MACHINE (DEGREASER) 
226 
228 
SEALED SYSTEM 
229 
SMALL CLEANER 
227 
230 
SOLVENT 
228 
SOLVENT CLEANING MACHINE (CLEANING MACHINE) (DEGREASER) 
229 
231 
SOLVENT/AIR INTERFACE 
230 
232 
SOLVENT/AIR INTERFACE AREA 
231 
233 
TOTAL VOC VAPOR PRESSURE (VOC COMPOSITE PARTIAL PRESSURE) 
232 
234 
VAPOR CLEANING MACHINE 
Appx I 235 
VAPOR LEVEL CONTROL SYSTEM 
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233 
236 
VOC CONTENT OF MATERIAL 
234 
237 
WIPE CLEANING 
SECTION 300 – STANDARDS 
301 
GENERAL REQUIREMENTS FOR SOLVENT CLEANING OPERATIONS 
SOLVENT HANDLING REQUIREMENTS 
302 
NON-VAPOR CLEANING MACHINE REQUIREMENTS  
EQUIPMENT REQUIREMENTS FOR ALL CLEANING MACHINES 
303 
VAPOR CLEANING MACHINE REQUIREMENTS  
SPECIFIC OPERATING & SIGNAGE REQUIREMENTS FOR CLEANING MACHINES 
304 
EMISSION CONTROL SYSTEM (ECS) REQUIREMENTS  
SOLVENT SPECIFICATIONS FOR NON-VAPOR CLEANING AND DEGREASING 
305 
NON-VAPOR BATCH CLEANING MACHINES 
306 
NON-VAPOR IN-LINE CLEANING MACHINES 
307 
SPECIAL NON-VAPOR CLEANING SITUATIONS 
308 
EXEMPTIONS 
309 
REQUIREMENTS FOR AIR POLLUTION CONTROL EQUIPMENT AND ECS 
MONITORING EQUIPMENT 
SECTION 400 – ADMINISTRATIVE REQUIREMENTS (NOT APPLICABLE) 
401 
COMPLIANCE SCHEDULE 
SECTION 500 – MONITORING AND RECORDS 
501 
RECORDKEEPING AND REPORTING 
502 
ECS RECORDKEEPING REQUIREMENTS 
502 
503 
COMPLIANCE DETERMINATION AND TEST METHODS 
APPENDIX TO RULE 331 
VAPOR CLEANING MACHINES AND EMISSION CONTROL SYSTEMS 
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Revised 07/13/88; Revised 06/22/92; Revised 06/19/96; Revised 04/07/99; Revised 04/21/04; 
Revised 09/25/13; Revised MM/DD/YYYY 
MARICOPA COUNTY AIR POLLUTION CONTROL REGULATIONS 
REGULATION III – CONTROL OF AIR CONTAMINANTS 
RULE 331 (SOLVENT CLEANING) 
SECTION 100 – GENERAL 
101 
PURPOSE: To limit the emissions of volatile organic compounds (VOCs) from solvent 
cleaning operations. 
102 
APPLICABILITY: This rule is applicable to operations using VOC-containing solvents to 
remove impurities from exterior or interior surfaces. Compliance with the provisions of 
this rule shall not relieve any person subject to the requirements of this rule from 
complying with any other federally enforceable requirements. In such case, the more 
stringent requirement shall apply. In any instance where more than one of the 
requirements set forth in this rule may be applicable, the most restrictive requirement 
shall apply. 
102.1 NSPS & NESHAP: In addition to this rule, facilities may be subject to New Source 
Performance Standards (NSPS) in Rule 360 and/or to National Emission 
Standards for Hazardous Air Pollutants (NESHAP) in Rule 370 of the Maricopa 
County Air Pollution Control Regulations (MCAPCR). 
Solvents regulated by this rule may also be regulated by New Source 
Performance Standards (NSPS) in Rule 360 of these rules and/or National 
Emission Standards for Hazardous Air Pollutants (NESHAPs) in Rule 370 of 
these rules. 
308.5 
102.2 Vehicle Refinishing: Dip cleaning of vehicle or mobile equipment surfaces is 
subject to this rule. 
308.1c(2) 102.3 Aerospace: Wipe cleaning of aerospace components is subject to Rule 348 
(Aerospace Manufacturing and Rework Operations) of the MCAPCR these rules, 
whereas the cleaning of aerospace components in a dip tank or a cleaning 
machine is subject to this rule Rule 331. 
102.3 Partial or conditional exemptions from this rule are set forth in Section 308 of 
this rule. 
308.2 103 
PARTIAL EXEMPTIONS from Section 300: The following are exempt from sections of 
Section 300 of this rule as noted: 
308.2a 
103.1 Wipe Cleaning: Wipe cleaning is only subject to Sections 301.1 and 501 of this 
rule. The provisions of Sections 302 through 307 of this rule do not apply to wipe 
cleaning. Recordkeeping Provisions in Section 500 of this rule do apply to wipe 
cleaning. 
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308.2b 
103.2 Small Cleaners: The provisions of Sections 301.3 through 302.4 303 through 307 
of this rule shall not apply to any non-vapor small cleaners with either a 
maximum capacity of one gallon or less, or a liquid surface area of one square 
foot or less, except that these shall be covered when work is not being 
processed. cleaning machine (degreaser) or dip-tank fitting either of the 
following descriptions, except that these shall be covered when work is not being 
processed: 
(1) A small cleaner having a liquid surface area of 1 square foot (0.09 square
meters) or less, or
(2) A small cleaner having a maximum capacity of one gallon (3.79 liters) or
less.
308.3 
103.3 Standard Industrial Classification (SIC) Codes Exemptions from Section 302.1 
304: The U.S. Government Printing Office “Standard Industrial Classification 
Manual, 1987” (and no future editions) is incorporated by reference and is on file 
at the Maricopa County Air Quality Department. The following SIC codes are 
exempt from Section 302.1 304 of this rule: 
a. Electronic products for space vehicles and communications equipment in
Industry Group 366 (Communications Equipment): SIC codes 3661, 3663, and
3669. 
b. Industry Group 367 (Electronic Components And Accessories): SIC codes
3677, 3678, and 3679.
c. Industry Group 376 (Guided Missiles And Space Vehicles And Parts): SIC
code 3769.
d. Non-furniture medical devices included in Standard Industrial Classification
Industry Group 384 (Surgical, Medical, And Dental Instruments And Supplies):
(SIC) codes 3841, 3843, 3844, or 3845, and products for internal use in 3842.
The U.S. Department of Labor, Occupational Safety and Health Administration
(OSHA) “Standard Industrial Classification (SIC) Manual” can be found on the
OSHA website at: https://www.osha.gov/data/sic-manual.
308.3(c) 103.4 Production processes having clean-room standards equal to or more stringent 
than clean room classification ISO 14644-1:2015 (Class 8) are exempt from 
Section 302.1 of this rule. class 100,000 (particles/m 3); and 
308.3(d) 103.5 Low viscosity solvent used to clean an aerospace component if the Federal 
Aviation Authority, the U.S. Department of Defense, or a U.S. Military 
specification designates that the cleanliness of the component is critical to the 
flight safety of a complete aerospace vehicle are exempt from Section 302.1 of 
this rule. By January 1, 2001, Any such solvents shall be listed in a Maricopa 
County Air Pollution Permit, conditioned upon a sufficient demonstration by the 
user that no compliant substitute exists. 
308.4 Comfort Fans: The Section 303.1(a) prohibition against fans and fan-drafts being 
close to cleaning machines does not apply to a totally enclosed cleaning 
machine that cannot be penetrated by drafts. 
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308.6 
103.6 Aerosol cans, squirt bottles, and other solvent containers intended for handheld 
use shall meet the requirements in Sections 301.1 and 500 of this rule. 
308.7 
103.7 A Low-VOC Cleaner is subject only to Sections 301.1, 301.2, 302.5(a), 501.5(a), 
and 501.6 301, 302, 307.1, 501.1(a), and 501.2 of this rule. 
104 
TOTAL CATEGORICAL EXEMPTIONS: This rule does not apply to: 
102.2 a. 
104.1 A solvent cleaning operation that is subject to or specifically exempted by an 
EPA State Implementation Plan (SIP) approved version of another rule within the 
MCAPCR Regulation III of these rules. 
b.
104.2 Janitorial cleaning.
c.
104.3 Testing for surface cleanliness or the cleaning of laboratory equipment at the
laboratory. 
d.
104.4 A cleaning-solvent that meets any of the following:
(1)
a. Is composed of at least 98% water by either weight or volume; or
(2)
b. Contains only water and material which is a dry solid before mixing with
water; or 
(3)
c. Has a VOC content not exceeding 20 grams per liter (0.17 lb/gal).
308.1 Categorical Exemptions:
308.1(a) 
Industries and cleaning operations that are not regulated by this rule include, 
but are not limited to, the following EPA approved versions of the VOC rules in 
Regulation III of these rules:  
(1) Dry cleaning with petroleum solvents (Rule 333);
(2) Printing and graphic arts coating (Rule 337);
(3) Semiconductor manufacturing (Rule 338);
(4) Automotive windshield washer fluid (Rule 344); and
(5) Architectural Coating (Rule 335).
308.1(b) 104.5 All operations regulated by the following NESHAPs are exempt from Rule 331: (1) 
National Emission Standards for Halogenated Solvent Cleaning (40 CFR 63, 
subpart T). This includes the de minimis amounts of solvent VOCs that are 
exempted by subpart T. All operations regulated by National Emission Standards 
for Perchloroethylene for Dry Cleaning Facilities (40 CFR 63, Subpart M). 
308.1(c) 104.6 Exemptions for Qualified Operations: Cleanup of Coating-Application Equipment: 
Operations involving the cleanup of coating-application equipment that are 
subject to or specifically exempted by an EPA SIP-approved version of another 
source-specific rule within the MCAPCR Regulation III of these rules are exempt 
from Rule 331. Examples include Rule 336 (Surface Coating Operations and 
Industrial Adhesive Application Processes), Rule 342 (Coating Wood Furniture 
and Fixtures), and Rule 346 (Coating Wood Millwork). 
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SECTION 200 – DEFINITIONS: For the purpose of this rule, the following definitions
shall apply, in addition to those definitions found in Rule 100 (General Provisions and 
Definitions) of these rules. In the event of any inconsistency between any of the MCAPCR 
Maricopa County Air Pollution Control Rules, the definitions in this rule take precedence. 
201 
AGITATION, AGITATED: A means or state that moves cleaning liquid continuously back 
and forth, or up and down. This includes such motion created by sound waves, and to 
the splashing of a rinse stream operated at a pressure that creates a trajectory 
exceeding 2 feet along the horizontal plane intersecting the nozzle when the nozzle is at 
a 45° angle above the plane. Liquid motion incidental to a continuous entrance or 
withdrawal of objects undergoing cleaning is not agitation. 
202 
BATCH CLEANING MACHINE: A solvent cleaning machine in which individual parts or a 
set of parts move through the entire cleaning cycle before new parts are introduced into 
the solvent cleaning machine. A solvent cleaning machine, such as a ferris wheel or a 
cross-rod degreaser, that cleans multiple batch loads simultaneously and is manually 
loaded, is a batch cleaning machine. 
203 
BLASTING/MISTING WITH SOLVENT: Cleaning with an applicator that propels 
cleaning-solvent through the air with a pressure exceeding 10 psig (516 mm Hg), or that 
atomizes the solvent into mist and/or droplets. 
204 
CABINET STYLE CLEANING MACHINES: A solvent cleaning machines typically similar 
in design to domestic dishwashers that are completely enclosed except for optional 
stack and have their own reservoir and sump. 
205 
CARRY-OUT: Solvent carried out of a cleaning machine along with a part being 
removed from the cleaning machine. The solvent may exist as a liquid coating the part 
or the part’s hanger, or as a liquid entrapped in cavities and irregular surfaces or 
entrapped by capillary action within or on the part. 
206 
CLEANING-SOLVENT: Solvent used for cleaning that contains more than 2.0% VOC by 
weight and more than 20 grams of VOC per liter (0.17 lb/gal). 
207 
CONFORMING SOLVENT: A cleaning-solvent having a total VOC vapor pressure at 68° F 
(20° C) not exceeding 1 millimeter of mercury column (mm Hg). 
208 
DEGREASER: See SOLVENT CLEANING MACHINE. 
208 
DIP TANK: A container holding solvent used for dipping or coating an object. An object 
may be immersed in a dip tank, or it may be suspended in a vapor coming from the tank. 
209 
DRY SOLID: Any substance that appears and feels dry. Evaporating solids, all of which 
have a strong odor, are not included. 
210 
EMISSION CONTROL SYSTEM (ECS): A system, approved in writing by the Control 
Officer, to reduce for reducing emissions of volatile organic compounds. Such a system 
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consists of an emissions collection system and an emissions processing subsystem. 
consisting of both a capture system and control device(s). 
211 
FILTRATION DEVICE: A filter composed of porous material (i.e., canvas bag) which 
collects and removes contaminants from solvent. 
211 
212 
FLUSHING WITH SOLVENT: Introducing cleaning-solvent directly into the internal 
space(s) of an object or assembly using a hose or pipe. Rinsing the outside of an object 
or assembly and swishing an object or assembly in cleaning-solvent are not considered 
flushing with solvent. Such activities must comply with Section 301.3 303.1 of this rule. 
212 
213 
FREEBOARD HEIGHT: 
212.1 
213.1 Batch Cleaning Machine: The vertical distance from the solvent/air interface to 
the least elevated point of the top-rim when the cover is open or removed, 
measured during idling mode. 
212.2 
213.2 In-Line Cleaning Machine: The vertical distance from the solvent/air interface to 
the lowest entry/exit point, measured during idling mode. 
213 
214 
FREEBOARD RATIO: The freeboard height divided by the smaller of either the length or 
width of the solvent cleaning machine. The ratio of the solvent cleaning machine 
freeboard height to the smaller interior dimension (length, width, or diameter) of the 
solvent cleaning machine. 
215 
FULLY SUBMERGED: Any material or object which is maintained below the surface of 
the solvent with no portions exposed to the ambient air.  
214 
216 
HEATED SOLVENT: Any cleaning-solvent which is heated by a device to a temperature 
exceeding 120° F (49° C). 
215 
217 
IMPERVIOUS: Neither absorbing, adsorbing, nor allowing penetration through, by liquid 
or vapors. 
216 
218 
IN-LINE CLEANING MACHINE (CONTINUOUS CLEANING MACHINE): A solvent cleaning 
machine that uses an automated handling system, typically a conveyor or automated 
arm(s), to automatically provide a continuous supply of items to be cleaned. The 
cleaned item leaves by a route different from its entry route. 
217 
219 
JANITORIAL CLEANING: The cleaning of building or facility components to keep work 
areas in clean condition. Building or facility components include, but are not limited to, 
floors, ceilings, walls, windows, doors, stairs, bathrooms, furnishings, textiles, wash 
rags, uniforms, and exterior surfaces of office equipment. 
218 
220 
LEAK: A visible cleaning-solvent liquid leak at a rate of three or more drops per minute, 
or a puddle greater than one square inch. 
The state or condition in which a cleaning-solvent, excluding a Low-VOC Cleaner, is 
allowed to seep or drip, or otherwise enters or escapes, at either of the following rate or 
magnitude: 
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218.1 Three or more drops of liquid cleaning-solvent per minute; or 
218.2 Any puddle of cleaning-solvent greater than 1 square inch. 
219 
221 
LOW-VOC CLEANER: Any solution or homogeneous suspension that, as used, contains 
less than 25 50 grams of VOC per liter of material (0.21 0.42 lb VOC/gal) or is at least 
95% water by weight or volume as determined by an applicable test method in Section 
502 503 of this rule. 
220 
222 
MAKE-UP SOLVENT: A cleaning-solvent that replaces solvent lost through evaporation 
or other means, and that is added to the solvent remaining in a cleaning machine 
(degreaser) to bring solvent quantity to the desired level. 
221 
MATERIAL VOC CONTENT: See VOC CONTENT OF MATERIAL. 
222 
223 
NON-CONFORMING SOLVENT: A cleaning-solvent having a total VOC vapor pressure at 
68°F (20°C) exceeding 1 millimeter of mercury column (mm Hg). 
224 
NON-VAPOR CLEANING MACHINE: SOLVENT CLEANING MACHINE (CLEANING 
MACHINE) (DEGREASER) Any liquid container and ancillary equipment designed to 
clean surfaces and/or remove surface contaminants using cleaning-solvents at 
temperatures that do not exceed the solvent boiling point. 
223 
ORGANIC COMPOUND: Any compound of carbon, excluding carbon monoxide, carbon 
dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate. 
225 
PARTS PER MILLION BY VOLUME DRY (PPMVD): A unit of proportion used to express 
concentration that is corrected to a dry basis. 
224 
226 
REFRIGERATED FREEBOARD CHILLER: A control device which is mounted above any 
cooling-water jacket or primary condenser coils, consisting of secondary coils which 
carry a refrigerant to provide a chilled air blanket above the solvent vapor/air interface 
to reduce emissions from the cleaning machine (degreaser) bath. 
225 
227 
REMOTE RESERVOIR CLEANING MACHINE (DEGREASER): Any non-vapor cleaning 
machine (degreaser) in which the reservoir for storing the cleaning-solvent is 
completely separated by impervious surfaces from the sink or basin where cleaning is 
performed, except for a connecting tube or passage through which solvent returns to 
the reservoir when cleaning is stopped. 
226 
228 
SEALED SYSTEM: An Air-tight or Airless Cleaning System that is operated and equipped 
pursuant to Section 302.1(c) 304.3 of this rule. 
308.2b 229 
SMALL CLEANER: A cleaning machine that has a liquid surface area of 1 square foot 
(0.09 square meters) or less or has a maximum capacity of one gallon (3.79 liters) or 
less. 
227 
230 
SOLVENT: For the purpose of this rule, any VOC-containing liquid or vapor which is used 
to dissolve, clean, strip, or remove impurities, coatings, contaminants, or films from 
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surfaces or from internal spaces and voids. In addition to VOC-containing solvents, this 
also includes plain water and mixtures containing water. 
228 
SOLVENT CLEANING MACHINE (CLEANING MACHINE) (DEGREASER): Any liquid 
container and ancillary equipment designed to clean surfaces and/or remove surface 
contaminants using cleaning-solvents. 
229 
231 
SOLVENT/AIR INTERFACE: 
229.1 231.1 Non-Vapor Cleaner: The location of contact between the liquid solvent and the 
air. 
229.2 231.2 Vapor Cleaner: The location of contact between the concentrated layer of 
solvent vapor and the air. 
230 
232 
SOLVENT/AIR INTERFACE AREA: 
230.1 232.1 Non-Vapor Cleaner: 
a. With Included/Integral Reservoir: The surface area of liquid cleaning-solvent
that is exposed to the air.
b. With Remote Reservoir: The surface area of the solvent sink or work area.
230.2 232.2 Vapor Cleaner: The area of the horizontal plane that is located halfway between 
the highest and lowest points of the primary condenser coils and which contacts 
the interior walls of the cleaning machine. 
231 
233 
TOTAL VOC VAPOR PRESSURE (VOC COMPOSITE PARTIAL PRESSURE): Within a 
solution or homogenous mixture, it is the sum of the partial pressures of all those 
components that are defined as VOCs, calculated according to the formula in Section 
503.1(f) 502.3 of this rule. 
232 
234 
VAPOR CLEANING MACHINE: Any batch or in-line cleaning machine in which solvent-
vapor from boiling cleaning-solvent is utilized for cleaning an object. 
Appx I 235 
VAPOR LEVEL CONTROL SYSTEM: A combination of a coolant sensing system and a 
vapor sensing system consisting of the following three sets of features: 
235.1 A condenser flow switch and thermostat which shuts off the sump heat if either 
the condenser coolant stops circulating or becomes warmer than 85° F (29° C); 
and 
235.2 A manually-reset safety switch which turns off the sump heater if the 
temperature sensor senses that the temperature is rising above the designed 
operating level at the vapor/air interface; and 
235.3 A manually-reset switch which turns off the spray-system pump if the level of the 
vapor/air interface drops more than 4 inches (10 cm). 
233 
236 
VOC CONTENT OF MATERIAL (MATERIAL VOC CONTENT): The weight of VOC per 
volume of material, as calculated according to the formula in Section 503.1(g) of this 
rule. 
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234 
237 
WIPE CLEANING: That A cleaning method of removing contaminants from a surface by 
physically rubbing or automatically rubbing with a porous or absorbent material, such as 
a rag, paper, sponge, or cotton swab, moistened with a solvent. 
SECTION 300 – STANDARDS 
301 
GENERAL REQUIREMENTS FOR SOLVENT CLEANING OPERATIONS SOLVENT 
HANDLING REQUIREMENTS: An owner or operator subject to Any person to whom this 
rule applies must shall comply with all of the following: 
301.1 Solvent Handling Requirements: All cleaning-solvent, including solvent soaked 
materials, shall be kept in closed, leak free, impervious containers that are 
opened only when adding or removing material. 
a. Porous or absorbent materials used for wipe cleaning shall be stored in
closed containers when not in use.
b. Each container shall be clearly labeled with its contents.
301.2 If any cleaning-solvent escapes from a container: 
301.2(a) 
c. Wipe up or otherwise remove any cleaning-solvent that escapes from a 
container immediately if in accessible areas. 
301.2(b) 
d. For areas where access is not feasible during normal production, remove any 
cleaning-solvent that escapes from a container as soon as reasonably 
possible. 
e. Disposal of waste or surplus solvent shall be done in a manner that does not
promote VOC evaporation, such as, but not limited to, via sewage treatment
works or having the waste hauled off-site in sealed containers.
301.3 Unless records show that VOC-containing cleaning material was sent offsite for 
legal disposal, it will be assumed that it evaporated on site. 
302 
301.2 Equipment Requirements for All Cleaning Machines: Any person owner or 
operator who is operating a cleaning machine to which this rule applies must 
comply with all of the following: 
302.1(a) a. Provide a leak free, impervious container (degreaser) for the solvents and the 
articles being cleaned. The VOC-containment portion shall be impervious to 
VOC-containing liquid and vapors. 
302.1(b) b. No surface of any freeboard required by this rule shall have an opening or 
duct through which VOC can escape to the atmosphere, except as controlled 
by an ECS, or as required by OSHA. 
302.2 
c. Properly maintain and operate all cleaning machine equipment required by
this rule and any of its emission controls required by this rule.
303 
SPECIFIC OPERATING & SIGNAGE REQUIREMENTS FOR CLEANING MACHINES: 
303.1 301.3 Operating Requirements for Cleaning Machines: Any person owner or operator 
who cleans with cleaning-solvent, other than a Low-VOC Cleaner, must comply 
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with conform to all of the following operating requirements for cleaning 
machines: 
a. Fans: Do not locate nor position comfort fans in such a way as to direct
airflow across the opening of any cleaning machine. This prohibition does not
apply to a totally enclosed cleaning machine that cannot be penetrated by
drafts.
b. Cover: Do not remove any device designed to cover the solvent unless
processing work in the cleaning machine or maintaining the machine.
c. Draining: Drain cleaned parts for at least 15 seconds after cleaning or until
dripping ceases, whichever is later.
d. Spraying: If using a cleaning-solvent spray system,
(1) Use only a continuous, undivided stream (not a fine, atomized, or shower
type spray).
(2) Pressure at the orifice from which the solvent emerges shall not exceed
10 psig and shall not cause liquid solvent to splash outside of the solvent
container.
(3) In an in-line cleaning machine, a shower-type spray is allowed, provided
that the spraying is conducted in a totally confined space that is separated
from the environment.
(4) Provisions for exceptions to foregoing Sections 303.1 301.3(d)(1), (2), and
(3) are provided for in Section 302.5 307 of this rule.
e. Agitation: No person An owner or operator shall not cause agitation of a
cleaning-solvent in a cleaning machine by sparging with air or other gas.
Covers shall be placed over ultrasonic cleaners when the cleaning cycle
exceeds 15 seconds.
f.
No Porous Material: (1) Do not clean nor use porous or absorbent materials
to clean parts or products in a cleaning machine. For the purpose of this rule,
porous or absorbent materials include, but are not limited to, cloth, leather,
wood, and rope.
(2) Do not place an object with a sealed wood handle, including a brush, in or
on a cleaning machine.
(3) Do not place porous or absorbent materials, including, but not limited to,
cloth, leather, wood, and rope on a cleaning machine.
g. Vent Rates: The ventilation rate at the cleaning machine shall not exceed 65
cfm per square foot of evaporative surface (20 m
3/min./m
2), unless that rate
must be changed to meet a standard specified and certified by a Certified
Safety Professional, a Certified Industrial Hygienist, or a licensed professional
engineer experienced in ventilation, to meet health and safety requirements.
h. Hoist Speed: Limit the vertical speed of mechanical hoists moving parts in
and out of the cleaning machine to a maximum of 2.2 inches per second and
11 ft/min. (3.3 m/min.).
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i.
Contamination Prevention: Prevent cross contamination of solvents
regulated by Section 302.1 304 of this rule with low-VOC cleaners solvents
that are not so regulated. Use signs, separated work-areas, or other effective
means for this purpose. This includes those spray gun cleaning-solvents that
are regulated by another source-specific rule within Maricopa County Rules of
Regulation III these rules.
j.
Filtration Devices: If a filtration device (e.g., to remove oils, greases, sludge,
and fine carbon from cleaning-solvent) is inherent in the design of the
cleaning machine, then such filtration device shall be operated in accordance
with manufacturer’s specifications and in accordance with the following
requirements:
(1) The filtration device shall be operated in accordance with manufacturer’s
specifications. 
(2) The filtration device shall be maintained under the protective shelf in the
wash basin, when applicable. 
303.1(j)(1) 
(3) The filtration device shall be fully submerged in cleaning-solvent at all 
times during filtration. 
303.1(j)(2) 
(4) When the filtration device is completely saturated and must be removed 
from the cleaning machine, the filtration device shall be drained until no 
liquid can flow from the filtration device. Draining and drying such 
filtration device shall be conducted in a sealed container with no exhaust 
to the atmosphere or work area. 
303.1(j)(3) 
(5) After the filtration device is dry, the filtration device shall be stored in a 
closed, leak free, impervious container that is legibly labeled with its 
contents and that remains covered when not in use. Disposal of the 
filtration device shall be done in a manner that inhibits VOC evaporation 
and that is in compliance with appropriate/legal methods of disposal. 
303.2 
301.4 Signage Requirements: Any person owner or operator who uses cleaning-
solvent, other than Low-VOC Cleaner, in any solvent cleaning machine 
(degreaser) or dip tank shall provide on the machine, or within 3¼ feet (1 meter) 
of the machine, a permanent, conspicuous label or placard which includes, at a 
minimum, each of the following applicable instructions, or its equivalent:  
a. “Keep cover closed when parts are not being handled.” (This is not required
for remote reservoir cleaners.)
b. “Drain parts until they can be removed without dripping.”
c. “Do not blow off parts before they have stopped dripping.”
d. “Wipe up spills and drips as soon as possible; store used spill rags [or ‘wiping
material’] in covered container.”
e. “Don’t clean porous or absorbent materials in this tank.”
“Don’t leave cloth or any absorbent materials in or on this tank.”
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f.
For cleaning machines with moving parts such as hoists, pumps, or
conveyors, post: “Operating instructions can be obtained from _______,” listing
a person or place where the instructions are available.
304 
302 
SOLVENT SPECIFICATIONS FOR NON-VAPOR CLEANING MACHINE REQUIREMENTS 
AND DEGREASING: 
302.1 Solvent Specifications for Non-Vapor Cleaning Machines: [Operating 
requirements specifically for vapor cleaning machines are in the Appendix.] All 
cleaning-solvents, except Low-VOC Cleaners, used in non-vapor non-boiling 
cleaning machines shall comply with one of the following requirements Section 
304.1 or Section 304.2 or Section 304.3, as follows: 
304.1 
a. Conforming Solvent: Use a cleaning-solvent having a total VOC vapor 
pressure at 68° F (20° C) not exceeding 1.0 millimeter of mercury column 
(mm Hg), as determined by the standards described in Section 500 of this 
rule; or 
304.2 
b. ECS: Use an ECS to capture and process VOC emissions in accordance with 
Section 304 IV of the Appendix within this rule; or 
304.3 
c. Sealed System: Use a Sealed System that is an Air-tight or Airless Cleaning 
System which is operated according to the manufacturer’s specifications and, 
unless otherwise indicated by the manufacturer, meets all of the following 
requirements: 
(1) Has a door or other pressure-sealing apparatus that is shut during each
cleaning and drying cycle; and
(2) Has a differential pressure gauge that always indicates the pressure in the
sealed chamber when occupied or in active use; and
(3) Any associated pressure relief device(s) shall be so designed and
operated as to prevent liquid cleaning-solvents from draining out.
305 
302.2 Non-Vapor Batch Cleaning Machines: An owner or operator who operates a non-
vapor batch cleaning machine shall comply with the following requirements 
(Low-VOC Cleaners are exempt from this section): 
Equipment requirements for non-vapor batch cleaning machines with remote 
reservoirs are set forth in Section 305.1 of this rule. Equipment standards 
applicable to non-vapor batch cleaning machines with internal reservoirs (non-
remote) are set forth in Section 305.2 of this rule. Non-vapor batch cleaning 
machines with either remote or internal reservoirs that use cleaning-solvents that 
are either heated, agitated or non-conforming are subject to additional provisions 
set forth in Section 305.3 of this rule.  
305.1 
a. With Remote Reservoir: A batch cleaning machine with remote reservoir, 
including cabinet type(s), shall be equipped with all of the following: 
305.1(a) (1) A sink-like work area or basin which is sloped sufficiently towards the 
drain so as to prevent pooling of cleaning-solvent. 
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305.1(b) (2) A single, unimpeded drain opening, or cluster of openings served by a 
single drain for the cleaning-solvent to flow from the sink into the 
enclosed reservoir. Such opening(s) shall be contained within a 
contiguous area not larger than 15.5 square inches (100 cm
2).
305.1(c) (3) Solvent Return: Provide a means for drainage of cleaned parts such that 
the drained solvent is returned to the cleaning machine. 
305.2 
b. With Internal Reservoir (Non-Remote): A batch cleaning machine without a 
remote reservoir shall be equipped with all of the following: 
305.2(a) 
(1) Have and use an internal drainage rack or other assembly that confines 
within the freeboard all cleaning-solvent dripping from parts and returns it 
to the hold of the cleaning machine (degreaser); and 
305.2(b) (2) Have an impervious cover which when closed prevents cleaning-solvent 
vapors in the cleaning machine from escaping into the air/atmosphere 
when not processing work in the cleaning machine. 
305.2(b)(1) (a) A cover shall be fitted so that in its closed position the cover is 
between the cleaning-solvent and any lip exhaust or other safety vent, 
except that such position of cover and venting may be altered by an 
operator for valid concerns of flammability established in writing and 
certified to by a Certified Safety Professional or a Certified Industrial 
Hygienist to meet health and safety requirements. 
305.2(b)(2) (b) A cover is not required when an ECS is used in accordance with 
Section 304 IV of the Appendix within this rule. 
305.2(c) 
(3) In the absence of additional applicable freeboard standards, freeboard 
height shall be not less than 6 inches (15.2 cm); and 
305.2(d) 
(4) The freeboard zone shall have a permanent, conspicuous mark that 
locates the maximum allowable solvent level which conforms to the 
applicable freeboard requirements. 
305.3 
c. Using Cleaning-Solvent that is Heated, or Agitated in a Non-Vapor Batch 
Cleaning Machine, or is Non-Conforming: If a non-vapor batch cleaning 
machine uses a cleaning-solvent at a temperature above 120° F (49° C), or 
agitates the solvent, or uses non-conforming solvent if allowed by Section 
305.3(d) of this rule, then comply with one of the following: 
305.3(a) 
(1) Remote Reservoir Cleaning Machines: For a remote reservoir cleaning 
machine, comply with Section 305.1 302.2(a) of this rule and one of the 
following: 
(a) Use a stopper in the drain whenever the sink or cabinet is empty of
solvent and nothing is being handled in the sink; or
(b) Cover the sink or cabinet whenever the sink or cabinet is empty of
solvent and nothing is being handled in the sink.
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305.3(b) (2) Internal Reservoir Cleaning Machines: For an internal reservoir cleaning 
machine, comply with Section 305.2 302.2(b) of this rule and one of the 
following either Section (1) or (2) that follow: 
(a) A Water Cover: A floating layer of water (insoluble in the solvent) at
least 1 inch thick, and a freeboard at least 6 inches above the top of
the solvent shall be present; or
(b) Freeboard and Cover:
(i) The basin shall have a freeboard ratio of 0.75 or greater and an
impervious cover shall cover the basin whenever work is not being
processed; and
(ii) If a non-conforming solvent is used, the cover shall be of a sliding
or rolling type which is designed to easily open and close in a
horizontal plane without disturbing the vapor zone.
305.3(c) 
(3) Cabinet Style: Keep a cabinet-style cleaning machine that it contains 
cleaning-solvent closed at all times, except when introducing or removing 
work from the machine. If blasting or misting with cleaning-solvent, also 
conform to the applicable requirements of Section 307 302.5 of this rule. 
305.4 
d. ECS Alternative: In lieu of meeting the requirements in Sections 302.2(a), 
302.2(b), and/or 302.2(c) of this rule, an owner or operator may comply by 
using an ECS that is approved in writing by the Control Officer and meets the 
requirements in Section 304. 
An owner and/or operator is allowed to meet the requirements of any one or 
combination of the requirements of Sections 305.1, 305.2 and/or 305.3 of 
this rule by operating an ECS in accordance with Section IV of the Appendix 
within this rule whenever any requirement of Sections 305.1, 305.2 and/or 
305.3 of this rule is not met. 
306 
302.3 Non-Vapor In-Line Cleaning Machines: No person shall An owner or operator 
who operates a non-vapor in-line cleaning machine using cleaning-solvent unless 
it shall comply complies with Sections 306.1, 306.2, and 306.3 of this rule 
302.3(a) through 302.3(e), or Section 302.3(f):  
306.1 Features: 
a. Carry-Out Prevention: Equip the cleaning machine with either a drying tunnel
or another means, such as a rotating basket, sufficient to prevent cleaned
parts from carrying out cleaning-solvent liquid or vapor.
b. Enclosed Design: An in-line cleaning machine shall be fully enclosed except
for entrance and exit portals.
c. Cover: During shutdown hours or if the cleaning machine is idle for more than
30 minutes, a cover shall be used to close the entrance and exit and any
opening greater than 16 square inches (104 cm
2).
306.2 
d. Minimized Openings: Entrances and exits should silhouette workloads so 
that the average clearance between parts and the edge of the cleaning 
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machine opening is either less than four inches (10 cm), or less than 10% of 
the width of the opening. 
306.3 
e. Freeboard Ratio: The machine shall have a freeboard ratio greater than or 
equal to 0.75. 
306.4 
f. ECS Alternative: In lieu of meeting the requirements in Sections 302.3(a) 
through Section 302.3(e) of this rule, an owner or operator may comply by 
using an ECS that is approved in writing by the Control Officer and meets the 
requirements in Section 304. 
An owner and/or operator is allowed to meet the requirements of any one or 
combination of Sections 306.1(b), 306.1(c), 306.2, and/or 306.3 of this rule by 
operating an ECS that controls VOC vapor from processes addressed by the 
requirement(s). Such ECS shall be operated in accordance with Section IV of 
the Appendix within this rule. 
305.3(d) 302.4 Non-Conforming Solvent used in a Non-Vapor Batch or In-Line Cleaning 
Machine: A non-conforming solvent may be used in operations to which this rule 
applies, if at least one of the following is met: 
305.3(d)(1) 
a. ECS or Sealed System: The emissions from the operation shall be controlled
by an ECS per Section 304.2 302.1(b) of this rule or by a Sealed System per
Section 304.3 302.1(c) of this rule; or
305.3(d)(2) 
b. Partial Exemption: The operation is exempted per Sections 103.1 and/or
103.2 308.2 of this rule; or
305.3(d)(3) 
c. Non-Vapor Batch Cleaning Machine: The operation is both exempted per
Section 103.3 308.3 of this rule and complies with Section 305.3 302.2(a) or
302.2(b) of this rule, as applicable; or
305.3(d)(3) 
d. Non-Vapor In-Line Cleaning Machine: The operation is both exempted per
Section 103.3 of the rule and for in-line machines, complies with all of Section
306 302.3 of this rule except Section 306.4 of this rule.
307 
302.5 Special Non-Vapor Cleaning Situations: 
307.1 
a. Blasting/Misting with Conforming Solvent or Low-VOC Cleaner: Any person 
owner or operator blasting or misting with conforming solvent or a low-VOC 
cleaner shall operate and equip the device(s) as follows: 
(1) Equipment: The device shall have internal drainage, a reservoir or sump,
and a completely enclosed cleaning chamber, designed so as to prevent
any perceptible liquid from emerging from the device; and
(2) Operation: The device shall be operated such that there is no perceptible
leakage from the device except for incidental drops from drained, removed
parts.
307.2 
b. Blasting/Misting with Non-Conforming Solvent: Any person owner or 
operator shall use a Sealed System pursuant to Section 302.1(c) 304.3 of this 
rule for all blasting or misting with a non-conforming solvent. 
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307.3 
c. High Pressure Flushing: Cleaning systems using cleaning-solvent that 
emerges from an object undergoing flushing with a visible mist or at a 
pressure exceeding 10 psig, shall comply as follows: 
(1) Conforming Solvent: For conforming solvent, use a containment system
that is designed to prevent any perceptible cleaning-solvent liquid from
becoming airborne outside the containment system, such as a completely
enclosed chamber.
(2) Non-Conforming Solvent: Use a Sealed System pursuant to Section
302.1(c) of this rule for non-conforming solvent.
307.4 
d. ECS Alternative: In lieu of meeting the requirements in Sections 302.5(a) 
and/or Section 302.5(b) of this rule, an owner or operator may comply by 
using an ECS that is approved in writing by the Control Officer and meets the 
requirements in Section 304. 
An owner and/or operator is allowed to meet the requirement(s) of Section 
307.1 and/or Section 307.2 of this rule by operating an ECS that controls VOC 
vapor from processes addressed by the requirement(s). The ECS shall be 
operated pursuant to Section IV of the Appendix within this rule. 
303 
VAPOR CLEANING MACHINE REQUIREMENTS: 
II.
BATCH-LOADED VAPOR CLEANING MACHINES:
III.
IN-LINE VAPOR CLEANING MACHINES:
Appx II, III (1)
No person shall operate a batch in-line vapor cleaning machine, unless the machine
meets National Emission Standards for Halogenated Solvent Cleaning (subpart T, Rule
370), as if the cleaning solvent in use were subject to subpart T standards.
Appx II, III (2)
No person shall operate a batch in-line vapor cleaning machine, unless the machine has
a vapor/air interface Fahrenheit temperature no greater than 30% of the solvent’s
boiling point temperature or no greater than 40.0°F (4.4°C), whichever is lower.
Appx II, III (3)
303.1 General Equipment Requirements for Vapor Cleaning Machines: An owner or
operator of a batch vapor cleaning machine or an in-line vapor cleaning machine 
shall ensure it is equipped with all of the following: 
Sections II(1) and II(2), III(1) and III(2) of this Appendix shall not apply, if a batch 
in-line vapor cleaning machine is equipped with all of the following: 
Appx II, III (3)(B) a. A Vapor Level Control System. 
Appx II, III (3)(D) b. Freeboard Ratio: A freeboard ratio that is greater than or equal to 0.75. 
Appx II(3)(F), III(3)(E) c. Refrigeration or ECS: Batch vapor cleaning machines or in-line vapor cleaning 
machines having any of the following descriptors an evaporative surface area 
equal to or greater than 10.75 ft² (1.0 m²), installed or subject to major 
modification after November 1, 1999, or having average monthly VOC 
emissions exceeding 31 pounds VOC per square foot of solvent surface area 
shall comply with Sections II(3)(F)(i), II(3)(F)(ii), or II(3)(f)(iii), III(3)(E)(i), 
III(3)(E)(ii), or III(3)(E)(iii) of this Appendix one of the following subsections:  
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(1) A refrigerated freeboard chiller where for which the chilled air blanket
temperature measured in degrees Fahrenheit at the coldest point on the
vertical axis through the horizontal center of the vapor/air interface either
shall be either no greater than 30% of the initial boiling point of the solvent,
measured in degrees Fahrenheit, or no greater than 40.0° F (4.4° C),
whichever is lower; or
(2) A refrigerated condenser coil (in place of an unrefrigerated coil) having a
minimum cooling capacity of 100% of the boiling-sump heat input rate and
where for which the chilled air blanket temperature requirements pursuant
to Section III(3)(E)(i) II(3)(F)(i) measured in degrees Fahrenheit at the
coldest point on the vertical axis through the horizontal center of the
vapor/air interface shall be either no greater than 30% of the initial boiling
point of the solvent, measured in degrees Fahrenheit, or no greater than
40.0° F (4.4° C), whichever is lower; or
(3) An ECS operated in accordance with Section 304 of this rule. IV of this
Appendix.
Appx II (3)(C), III(3)(C) d. Primary Condenser: A primary condenser that maintains an exit temperature 
not exceeding 85° F (29° C). Alternatively, a batch vapor cleaning machine 
may be equipped pursuant to Section 303.1(c)(2) II(3)(F)(ii) of this Appendix. 
Appx II(3)(G), III(3)(F) 
e. Water Separator: Water should not be visually detectable in the VOC-
containing solvent exiting the water separator. 
Appx II (3), (4) 303.2 Batch-Loaded Vapor Cleaning Machines: An owner or operator shall ensure a 
batch-loaded vapor cleaning machine meets the requirements in Section 303.1 
and all of the following: 
Sections II(1) and II(2) of this Appendix shall not apply, if a batch vapor cleaning 
machine meets all of the following: 
Appx II (3)(A) 
a. Cover: Equipped with an impermeable cover that is a sliding, rolling, fanning, 
or guillotine (bi-parting) type which is designed to easily open and close 
without disturbing the vapor zone. 
Appx II (3)(E)
b. Lip Exhausts: Batch-loaded vapor cleaning machines with lip exhausts shall
be controlled by an ECS.
Appx II (4)(A) 
c. Workloads: 
(1) A workload shall not occupy more than half of the cleaning machine’s
open-top area.
(2) The workload shall not be so massive that the vapor level drops more than
4 inches (10 cm), when the workload is removed from the vapor zone.
(3) The workload shall not be sprayed with cleaning-solvent above the
vapor/air interface level.
Appx II (4)(B) 
d. Carry-Out: Minimize cleaning-solvent carry-out by the following measures: 
(1) Orient the items being cleaned in such a way that the items drain easily
after cleaning.
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(2) Degrease the workload in the vapor zone at least 30 seconds or until
condensation ceases.
(3) For manual loading/unloading, tip out any pools of solvent on the cleaned
parts before removal.
(4) Allow parts to dry within the batch vapor cleaning machine until visually
dry.
Appx II (4)(C) 
e. Startup and Shutdown: The following sequence shall be used for startup and 
shutdown: 
(1) When starting the batch vapor cleaning machine, the cooling system shall
be turned on before, or simultaneously with, the sump heater.
(2) When shutting down the batch vapor cleaning machine, the sump heater
shall be turned off before, or simultaneously with, the cooling system.
Appx II (4)(D) 
f. Blasting: Blasting in a batch vapor cleaning machine shall be done within a 
Sealed System or be controlled by an ECS. 
Appx II (4)(E)
g. Records: Maintain records pursuant to Section 501 of this rule. An owner
and/or operator operating a batch vapor cleaning machine shall keep records
pursuant to Section 501 of this rule.
Appx III (3), (4) 
303.3 In-Line Vapor Cleaning Machines: An owner or operator shall ensure an in-line 
vapor cleaning machine meets the requirements in Section 303.1 and all of the 
following: 
Sections III(1) and III(2) of this Appendix shall not apply, if an in-line vapor 
cleaning machine is equipped with all of the following  
Appx III (3)(A) 
a. Cover: Within 10 minutes of turning off the solvent heating system, cover the 
entrance and exit and any opening greater than 16 square inches (104 cm2). 
Appx III (4)(A) 
b. Workloads: Entrances and exits should silhouette workloads so that The 
average clearance between parts and the edge of the in-line vapor cleaning 
machine opening is either less than 4 inches (10 cm) or less than 10% of the 
width of the opening. 
Appx III (4)(B) 
c. Carry-Out: Equip the in-line vapor cleaning machine with either a drying tunnel 
or another means, such as a rotating basket, sufficient to prevent cleaned 
parts from carrying out cleaning-solvent liquid or vapor. 
Appx III (4)(C) 
d. Startup and Shutdown: The following sequences shall be used for startup and 
shutdown: 
(1) When starting the in-line vapor cleaning machine, the cooling system shall
be turned on before, or simultaneously with, the sump heater.
(2) When shutting down the in-line vapor cleaning machine, the sump heater
shall be turned off before, or simultaneously with, the cooling system.
Appx III (4)(D) 
e. Records: Maintain records pursuant to Section 501 of this rule. An owner 
and/or operator operating an in-line vapor cleaning machine shall keep 
records pursuant to Section 501 of this rule. 
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Appx IV (1) 304 
EMISSION CONTROL SYSTEM (ECS) REQUIREMENTS: 
304.1 ECS Control Efficiencies: To meet the requirements pursuant to Section 302.1(b) 
of this rule, an ECS shall comply with one of the following: 
a. Overall ECS Efficiency: Operate an ECS that has an 85% overall VOC capture
and control efficiency, determined by applicable provisions in Section
503.1(c) of this rule; or
An Emission Control System (ECS) used pursuant to this rule shall consist of
a hood or enclosure to collect emissions, which are vented to a processing
device. The overall control efficiency (capture plus processing) of the system
shall not be less than 85%. The capture system shall have a ventilation rate
no greater than 65 cfm per square foot of evaporative surface (20
m
3/min./m
2), unless that rate must be changed to meet a standard specified
and certified by a Certified Safety Professional, a Certified Industrial
Hygienist, or a licensed professional engineer experienced in ventilation-
system design, that concerns health and safety requirements. The ECS shall
be approved by the Control Officer.
b. Alternative for Very Dilute Input: For VOC input-concentrations of less than
100 ppmvd (as propane) at the inlet of the ECS, the control efficiency is
satisfied if the VOC outlet concentration is less than or equal to 10 ppmvd (as
propane), determined by applicable provisions in Section 503.1(d) of this rule.
Appx IV (2), 309.1 304.2 Operation and Maintenance (O&M) Plan Required for ECS: 
309.1a 
a. An owner and/or operator shall provide create and maintain (an) O&M Plan(s) 
for any ECS and any ECS monitoring devices used pursuant to required by this 
rule or pursuant to a Maricopa County Air Quality Permit an air pollution 
control permit in accordance with Section 309 of this rule.  
309.1b 
b. Approval by Control Officer of Initial O&M Plan(s): An The owner and/or 
operator shall submit to the Control Officer for written approval the O&M 
Plan(s) of each ECS and each ECS monitoring device that is used pursuant to 
this rule. While the Control Officer is reviewing for approval the O&M Plan(s), 
an owner and/or operator shall comply with all the identified actions and 
schedules provided in each O&M Plan submitted for approval, unless notified 
otherwise by the Control Officer. After the Control Officer has issued written 
approval of the O&M Plan(s), an owner and/or operator shall continue to 
comply with all the identified actions and schedules provided in each O&M 
Plan. 
309.1a 
c. A The owner and/or operator shall comply with all the identified actions and 
schedules provided in each O&M Plan. 
309.1c 
Owner and/or Operator Revisions to Initial O&M Plan(s): If an owner and/or 
operator submits to the Control Officer revisions to the initial O&M Plan(s) 
and if such revisions have been approved in writing by the Control Officer, an 
owner and/or operator shall comply with the revisions to the initial O&M 
Plan(s). 
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309.1d 
Control Officer Modifications to Initial O&M Plan(s): After discussion with the 
owner and/or operator, the Control Officer may modify the O&M Plan(s) in 
writing prior to approval of the initial O&M Plan(s). An owner and/or operator 
shall then comply with the O&M Plan(s) that has been modified by the Control 
Officer. 
309.2 
304.3 Providing and Maintaining ECS Monitoring Devices: An owner and/or operator 
incinerating, adsorbing, or otherwise processing VOC emissions pursuant to this 
rule shall provide, properly install and maintain in calibration, in good working 
order and in operation, devices described in the facility’s O&M Plan that indicate 
temperatures, pressures, rates of flow, or other operating conditions necessary 
to determine if the ECS air pollution control equipment is functioning properly 
and is properly maintained. Records shall be kept pursuant to Section 502 of this 
rule which demonstrate that the ECS meets the overall control standard required 
by Section 304.1 of this rule and is operated in accordance with the equipment 
manufacturer's specifications. 
304.4 O&M Plan Responsibility: An owner or operator of a facility that is required to 
have an O&M Plan pursuant to Section 304.2 of this rule must fully comply with 
all O&M Plans that the owner or operator has submitted for approval, but which 
have not yet been approved, unless notified otherwise by the Control Officer in 
writing. 
304.5 O&M Plan Contents for an ECS: An O&M Plan for any ECS including any ECS 
monitoring devices shall include all of the following information: 
a. ECS equipment manufacturer;
b. ECS equipment model;
c. ECS equipment identification number or identifier that owner or operator
subject to this rule assigns to such ECS equipment when manufacturer’s
equipment identification number is unknown; and
d. Information required by Sections 502 and 503 of this rule.
Appx IV (4)
Test Methods for Determining Emission Control System Compliance: Test 
methods and compliance procedures for an ECS are in Section 502 of this rule. 
SECTION 400 – ADMINISTRATIVE REQUIREMENTS (NOT APPLICABLE) 
401 
COMPLIANCE SCHEDULE: 
401.1 ECS Installation at New Sources: For sources that commence construction after 
[revision date], compliance with the ECS requirements shall be achieved upon 
source startup. 
401.2 New Low-VOC Cleaner Limit: Upon adoption of this rule, an owner or operator 
using a low-VOC cleaner to comply with this rule shall discontinue purchase of 
materials that are non-compliant with the new low-VOC cleaner limit of this rule. 
The owner or operator may continue to use supplies of non-compliant low-VOC 
cleaner materials purchased prior to [date] until [six-month deadline date]. 
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SECTION 500 – MONITORING AND RECORDS 
501 
RECORDKEEPING AND REPORTING: Any person subject to this rule An owner or 
operator subject to this rule shall comply with the following recordkeeping 
requirements: 
501.1 Records shall be retained for a period of five years. 
501.2 Records shall be made available to the Control Officer no later than five business 
days upon verbal or written request. 
501.3 Records shall be made available to the Control Officer upon request by members 
of the public using the County’s public records request process. 
501.4 Records shall be kept on site at all times in a consistent and complete manner. 
501.1 
501.5 Current List:  
a. Maintain a current list of cleaning-solvents; state the VOC content of each in
pounds VOC per gallon of material or grams per liter of material.
b. A facility using any cleaning-solvent subject to the vapor-pressure limits of
Section 302.1(a) 304.1 of this rule shall have on site the written value of the
total VOC vapor-pressure of each such solvent, in one of the following forms:
(1) A manufacturer’s technical data sheet;
(2) A manufacturer’s safety data sheet (MSDS); or
(3) Actual test results.
501.2 
501.6 Usage Records: 
a. Monthly: Records of the amount of cleaning-solvent purchased or used shall
be totaled updated by the end of the month for the previous month. Show the
type and amount of each make-up solvent and all other cleaning-solvent to
which this rule is applicable.
b. Annually:
(1) Certain Concentrates: Use of concentrate that is used only in the
formulation of Low-VOC Cleaner shall be updated at least annually.
(2) Low-VOC Cleaner: An owner and/or operator need not keep a record of a
cleaning substance that is made by diluting a concentrate with water or
non-precursor organic compound(s) to a level that qualifies as a Low-VOC
Cleaner if records of the concentrate usage are kept in accordance with
this rule.
c. Grouping by VOC Content: For purposes of recording usage, an owner or
operator may give cleaning-solvents of similar VOC content a single group-
name, distinct from any product names in the group. The total usage of all the
products in that group is then recorded under just one name. (In such a case,
the owner or operator must also keep a separate list that identifies the
product names of the particular cleaning-solvents included under the group
name). To the group name shall be assigned the highest VOC content among
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the members of that group, rounded to the nearest tenth 10th of a pound of 
VOC per gallon of material, or to the nearest gram VOC per liter of material. 
501.7 Records of Disposal: Maintain records of the type, amount, and method of 
disposing of waste solvent. Records of legal disposal include but are not limited 
to shipping papers or quantity discharged to sewage treatment works.  
502 
ECS RECORDKEEPING REQUIREMENTS: An owner or operator shall maintain all of the 
following records in accordance with an approved O&M Plan for any required ECS: 
(IV, 3.A) ECS Operation and Maintenance Records: On each day that an ECS is used to 
comply with any provision of this rule, an owner and/or operator shall make a 
permanent record of the operating parameters of the key systems described 
in the O&M Plan. For each day or period in which the O&M Plan requires that 
maintenance be performed, a permanent record shall be made of the 
maintenance actions taken, within 24 hours of maintenance completion. An 
explanation shall be entered for scheduled maintenance that is not performed 
during the period designated in the O&M Plan. 
502.1 On each day a required ECS is used at a facility pursuant to this rule, the owner or 
operator shall make a permanent record of the key system operating parameters 
as required by the O&M Plan which may include the following, when applicable: 
a. Flow rates;
b. Pressure drops;
c. Temperature; or
d. Other operating conditions necessary to determine if the approved ECS is
functioning properly.
502.2 An explanation shall be recorded for periods of time an approved ECS is not 
operating. 
502.3 For each day or period the O&M Plan requires maintenance, the owner or 
operator shall make a permanent record of the maintenance actions taken within 
3 business days of the maintenance completion. 
502.4 Corrective action taken, if any. 
502.5 An explanation shall be entered for scheduled maintenance that is not performed 
during the period designated for it in the O&M Plan. 
(IV, 3B) 
502.6 Other Records Required when Complying via ECS: An owner and/or operator 
using an ECS pursuant to this rule shall maintain, in addition to the records 
required by Section 501.5 501.1 of this rule, daily monthly documentation 
showing the VOC content of the solvent material and the amount added for 
makeup. 
502 
503 
COMPLIANCE DETERMINATION AND TEST METHODS: When more than one test 
method is permitted for a determination, an exceedance of the limits established in the 
rule determined by any of the applicable test methods constitutes a violation of this 
rule. 
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502.1 
503.1 Compliance Determination: The following means shall be used to determine 
compliance with this rule. For routine information collection, the Control Officer 
may accept a manufacturers’ data sheet, data certified by an officer of the 
supplying company, or test data for the product model of inquiry. 
a. VOC Content: The VOC content of solutions, dispersions, emulsions, and
conforming solvents (reference Section 207 of this rule) shall be determined
by one of the following methods:
(1) South Coast Air Quality Management District (SCAQMD) Method 313-91
as referenced in Section 503.3(a) 502.2(f) of this rule; or
(2) Bay Area Air Quality Management District (BAAQMD) Method 31 as
referenced in Section 503.3(b) 502.2(e) of this rule. ; or
(3) Solids-free windshield washer solutions, in which all organic components
are VOCs, may be tested using Maricopa County Reference Method #100,
“Total Organic Carbon for Windshield Washer Fluids,” Maricopa County Air
Pollution Control Rule 344 (April 7, 1999). This method should only be
used for water-based solutions containing less than 5% VOC by weight.
b. Vapor Pressure: Pursuant to Sections 304 and 207 of this rule, Determination
of the total VOC vapor-pressure (VOC composite partial-pressure) in a
cleaning solution shall be performed as follows:
(1) For solutions known to be nearly or exactly 100% VOC, vapor pressure
shall be determined by ASTM D2879-9796 as referenced in Section
503.4(a) 502.2(g) of this rule; or
(2) For solutions for which is known the exact quantity and chemical makeup
of each evaporating component that is not a VOC, ASTM D2879-9796
(referencing Section 503.4(a) 502.2(g) of this rule) shall be used (to
determine the gross composite vapor pressure) in conjunction with
calculations using the vapor pressure formula in Section 503.1(f) 502.3 of
this rule.
(3) When a solution’s exact species and proportions are known for all
ingredients, the Control Officer may use the formula in Section 503.1(f)
502.3 of this rule in conjunction with standard reference texts or
databases that provide the vapor pressure value of each constituent, or a
combination of formula use and actual testing on real constituents
(referencing Section 503.4(a) 502.2(g) of this rule).
c. ECS Efficiency Compliance: An owner or operator that complies with Section
304.1(a) of this rule using an ECS shall demonstrate compliance using the
following methods and equations:
(1) Overall ECS Efficiency shall be determined using the following equation:
EffO = (EffCo x EffCa) / 100 
where, 
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EffO  = Overall ECS efficiency expressed as a percentage; and 
EffCo  = ECS control efficiency expressed as a percentage; and 
EffCa  = ECS capture efficiency expressed as a percentage. 
(1)
(2) The ECS control efficiency shall be determined by measuring the VOC
content of gaseous emissions entering and exiting the ECS using EPA 
Method 18, referenced in Section 503.2(e), or EPA Methods 25, 25A, and 
25B, referenced in Section 503.2(f) of this rule. 
The VOC content of gaseous emissions entering and exiting an ECS shall 
be determined by either EPA Method 18 referred to in Section 502.2(b) of 
this rule, or EPA Methods 25, 25a, and 25b referred to in Section 502.2(c) 
of this rule. 
(2)
(3) The ECS capture efficiency of an emission control device used pursuant to
Section 304.2, Section 305.4, Section 306.4, and/or Section 307.4 of this 
rule shall be determined either by the methods in Section 503.2(g) 
502.2(d) of this rule (EPA Methods 204, 204Aa, 204Bb, 204Cc, 204Dd, 
204Ee, and 204Ff) or by using mass balance calculation methods in 
concert with the methods in Section 503.2(b) 502.2(a) of this rule (EPA 
Methods 2, 2Aa, 2Cc, and 2Dd), and EPA guidance document, “Guidelines 
for Determining Capture Efficiency”, January 9, 1995. 
d. Alternative for Very Dilute Input: An owner or operator that complies with
Section 304.1(b) of this rule shall demonstrate compliance by using EPA
Method 25A referred to in Section 503.2(f) of this rule.
502.1(d) 
e. Temperature Measurement: Temperature measurements made pursuant to 
Section 214 of this rule to determine if a cleaning machine contains a “heated 
solvent” shall be done with an instrument having an accuracy and precision of 
no less than within 1 degree Fahrenheit. 
502.3 
f.
Formula for VOC Composite Partial Pressure (Equivalent to: Total VOC Vapor
Pressure): The VOC composite partial pressure shall be calculated by the
following equation:
(
)(
)
∑
∑
∑
=
=
=
+
+
=
m
j
n
i
i
i
e
e
w
n
i
i
i
i
c
M
W
M
W
W
M
VP
W
PP
1
1
1
18
where, 
i
W 
= 
Weight of the “i”th VOC compound in grams
w
W 
= 
Weight of water in grams
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We = 
Weight of the “j”th non-precursor organic compound in 
grams 
i
M 
=
Molecular weight of the “i”th VOC compound in grams per 
gram mole, e.g., one gram-mole of isopropyl alcohol weighs 
60 grams 
e
M 
=
Molecular weight of the “j”th non-precursor compound, e.g., 
1 gram-mole of acetone weighs 58 grams 
c
PP 
=
VOC composite partial pressure at 20°C in mm mercury (Hg) 
i
VP 
=
Vapor pressure of the “i”th VOC compound at 20°C in mm 
Hg 
18 = 
Weight of one gram-mole of water 
n = 
Total number of different (dissolved) VOCs 
m = 
Total number of different (dissolved) non-precursor organic 
compounds 
503.4 
g. Formula for VOC Content of Solvent: The VOC content of solvent shall be
calculated by the following equation:
VOC CONTENT OF MATERIAL as a percent =
W
W
W
m
s
w
es
W
−
−
 X 100% 
Using consistently either pounds or grams in the calculations, where: 
Ws
= 
Weight of volatile material in pounds (or grams), including 
water, non-precursor organic compounds, and dissolved 
vapors 
Ww 
= 
Weight of water in pounds (or grams) 
Wes
= 
Total weight of non-precursor organic compounds in pounds 
(or grams) 
Wm 
= 
Weight of total material in pounds (or grams) 
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VOC CONTENT OF MATERIAL in pounds per gallon (lbs/gal) or grams per liter (g/l) = 
W
W
W
m
s
w
es
V
−
−
Using consistently either English or metric measures in the calculations, where: 
Ws
= Weight of all volatile material in pounds (or grams) including 
VOC, water, non-precursor organic compounds and dissolved 
vapors 
Ww
=  Weight of water in pounds (or grams) 
Wes
=  Weight of all non-precursor organic compounds in pounds (or 
grams) 
Vm
=  Volume of total material in gallons (or liters) 
502.2 
503.2 EPA-Approved Test Methods Adopted Incorporated by Reference: The following 
test methods are approved for use for the purpose of determining compliance 
with this rule. The test methods are incorporated by reference in Appendix G of 
the MCAPCR. Alternative EPA-approved test methods may be used upon prior 
written approval from the Control Officer. When more than one test method is 
permitted for the same determination, an exceedance under any method will 
constitute a violation.  
The EPA test methods as they exist in the Code of Federal Regulations (CFR) 
(July 1, 2003), as listed below, are adopted by reference. The other test methods 
listed here are also adopted by reference, each having paired with it a specific 
date that identifies the particular version/revision of the method that is adopted 
by reference. These adoptions by reference include no future editions or 
amendments. Copies of test methods referenced in this Section 502 are 
available at the Maricopa County Air Quality Department. 
a. EPA Methods 1 (“Sample and Velocity Traverses for Stationary Sources”) and
1A (“Sample and Velocity Traverses for Stationary Sources with Small Stacks
or Ducts”) (40 CFR 60, Appendix A-1).
502.2(a) 
b. EPA Methods 2 (“Determination of Stack Gas Velocity and Volumetric Flow
Rate”), 2A (“Direct Measurement of Gas Volume Through Pipes and Small
Ducts”), 2C (“Determination of Stack Gas Velocity and Volumetric Flow rate in
Small Stacks or Ducts”), and 2D (“Measurement of Gas volumetric Flow Rates
in Small Pipes and Ducts”) All 4 of the foregoing methods are in (40 CFR 60,
Appendix A-1).
c. EPA Methods 3 (“Gas Analysis for the Determination of Dry Molecular
Weight”), 3A (“Determination of Oxygen and Carbon Dioxide Concentrations in
Emissions From Stationary Sources (Instrumental Analyzer Procedure”), 3B
(“Gas Analysis for the Determination of Emission Rate Correction Factor or
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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Excess Air”), and 3C (“Determination of Carbon Dioxide, Methane, Nitrogen, 
and Oxygen from Stationary Sources”) (40 CFR 60, Appendix A-2). 
d. EPA Method 4 (“Determination of Moisture Content in Stack Gases”) (40 CFR
60, Appendix A-3).
502.2(b) 
e. EPA Method 18 (“Measurement of Gaseous Organic Compound Emissions by
Gas Chromatography”) (40 CFR 60, Appendix A-6).
502.2(c) 
f.
EPA Methods 25 (“Determination of Total Gaseous Non-Methane Organic
Emissions as Carbon”), 25A (“Determination of Total Gaseous Organic
Concentration Using a Flame Ionization Analyzer”), and 25B (“Determination
of Total Gaseous Organic Concentration Using a Nondispersive Infrared
Analyzer”) (40 CFR 60, Appendix A-7).
502.2(d) 
g. EPA Test Methods 204 (“Criteria for and Verification of a Permanent or
Temporary Total Enclosure”), 204A (“Volatile Organic Compounds Content in
Liquid Input Stream”), 204B (“Volatile Organic Compound Emissions in
Captured Stream”), 204C (“Volatile Organic Compound Emissions in Captured
Stream (Dilution Technique)”), 204D (“Volatile Organic Compound Emissions
in Uncaptured Stream from Temporary Total Enclosure”), 204E (“Volatile
Organic Compound Emissions in Uncaptured Stream from Building
Enclosure”), and 204F (“Volatile Organic Compounds Content in Liquid Input
Stream (Distillation Approach)”) (40 CFR 51, Appendix M) and EPA guidance
document, “Guidelines for Determining Capture Efficiency” January 9, 1995.
502.2(h) 
h. EPA guidance document, “Guidelines for Determining Capture Efficiency”,
January 9, 1995.
503.3 EPA-Approved California Air Resources Board (CARB) Test Methods 
Incorporated by Reference: 
502.2(f) 
a. California’s South Coast Air Quality Management District (SCAQMD) Method
313-91 (February April 1997), “Determination of Volatile Organic Compounds
(VOC) by Gas Chromatography/Mass Spectrometry (GC/MS)”.
502.2(e) 
b. California’s Bay Area Air Quality Management District (BAAQMD) Method 31
(May 18, 2005 April 15, 1992), “Determination of Volatile Organic Compounds
in Paint Strippers, Solvent Cleaners, and Low Solids Coatings.”.
503.4 EPA-Approved American Society for Testing and Materials (ASTM) Standard 
Incorporated by Reference: 
502.2(g) 
a. American Society for Testing and Materials (ASTM) Method D2879-9796,
“Test Method for Vapor Pressure-Temperature Relationship and Initial
Decomposition Temperature of Liquids by Isoteniscope” (1996).
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MARICOPA COUNTY AIR POLLUTION CONTROL REGULATIONS 
REGULATION III – CONTROL OF AIR CONTAMINANTS 
RULE 331 (SOLVENT CLEANING) 
INDEX 
SECTION 100 – GENERAL 
101 
PURPOSE 
102 
APPLICABILITY 
103 
PARTIAL EXEMPTIONS 
104 
TOTAL CATEGORICAL EXEMPTIONS 
SECTION 200 – DEFINITIONS 
201 
AGITATION, AGITATED 
202 
BATCH CLEANING MACHINE 
203 
BLASTING/MISTING WITH SOLVENT 
204 
CABINET STYLE CLEANING MACHINE 
205 
CARRY-OUT 
206 
CLEANING-SOLVENT 
207 
CONFORMING SOLVENT 
208 
DIP TANK 
209 
DRY SOLID 
210 
EMISSION CONTROL SYSTEM (ECS) 
211 
FILTRATION DEVICE 
212 
FLUSHING 
213 
FREEBOARD HEIGHT 
214 
FREEBOARD RATIO 
215 
FULLY SUBMERGED 
216 
HEATED SOLVENT 
217 
IMPERVIOUS 
218 
IN-LINE CLEANING MACHINE 
219 
JANITORIAL CLEANING 
Return to list of attachments
Clean version of draft Rule 331
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220 
LEAK 
221 
LOW-VOC CLEANER 
222 
MAKE-UP SOLVENT 
223 
NON-CONFORMING SOLVENT 
224 
NON-VAPOR CLEANING MACHINE 
225 
PARTS PER MILLION BY VOLUME DRY (PPMVD) 
226 
REFRIGERATED FREEBOARD CHILLER 
227 
REMOTE RESERVOIR CLEANING MACHINE 
228 
SEALED SYSTEM 
229 
SMALL CLEANER 
230 
SOLVENT 
231 
SOLVENT/AIR INTERFACE 
232 
SOLVENT/AIR INTERFACE AREA 
233 
TOTAL VOC VAPOR PRESSURE (VOC COMPOSITE PARTIAL PRESSURE) 
234 
VAPOR CLEANING MACHINE 
235 
VAPOR LEVEL CONTROL SYSTEM 
236 
VOC CONTENT OF MATERIAL 
237 
WIPE CLEANING 
SECTION 300 – STANDARDS 
301 
GENERAL REQUIREMENTS FOR SOLVENT CLEANING OPERATIONS 
302 
NON-VAPOR CLEANING MACHINE REQUIREMENTS 
303 
VAPOR CLEANING MACHINE REQUIREMENTS 
304 
EMISSION CONTROL SYSTEM (ECS) REQUIREMENTS 
SECTION 400 – ADMINISTRATIVE REQUIREMENTS 
401 
COMPLIANCE SCHEDULE 
SECTION 500 – MONITORING AND RECORDS 
501 
RECORDKEEPING AND REPORTING 
502 
ECS RECORDKEEPING REQUIREMENTS 
503 
COMPLIANCE DETERMINATION AND TEST METHODS 
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Revised 07/13/88; Revised 06/22/92; Revised 06/19/96; Revised 04/07/99; Revised 04/21/04; 
Revised 09/25/13; Revised MM/DD/YYYY 
MARICOPA COUNTY AIR POLLUTION CONTROL REGULATIONS 
REGULATION III – CONTROL OF AIR CONTAMINANTS 
RULE 331 (SOLVENT CLEANING) 
SECTION 100 – GENERAL 
101 
PURPOSE: To limit the emissions of volatile organic compounds (VOCs) from solvent 
cleaning operations. 
102 
APPLICABILITY: This rule is applicable to operations using VOC-containing solvents to 
remove impurities from exterior or interior surfaces. 
102.1 NSPS & NESHAP: In addition to this rule, facilities may be subject to New Source 
Performance Standards (NSPS) in Rule 360 and/or to National Emission 
Standards for Hazardous Air Pollutants (NESHAP) in Rule 370 of the Maricopa 
County Air Pollution Control Regulations (MCAPCR). 
102.2 Vehicle Refinishing: Dip cleaning of vehicle or mobile equipment surfaces is 
subject to this rule. 
102.3 Aerospace: Wipe cleaning of aerospace components is subject to Rule 348 
(Aerospace Manufacturing and Rework Operations) of the MCAPCR, whereas the 
cleaning of aerospace components in a dip tank or a cleaning machine is subject 
to this rule. 
103 
PARTIAL EXEMPTIONS: 
103.1 Wipe Cleaning: Wipe cleaning is only subject to Sections 301.1 and 501 of this 
rule. 
103.2 Small Cleaners: The provisions of Sections 301.3 through 302.4 of this rule shall 
not apply to non-vapor small cleaners with either a maximum capacity of one 
gallon or less, or a liquid surface area of one square foot or less, except that 
these shall be covered when work is not being processed. 
103.3 Standard Industrial Classification (SIC) Codes Exempt from Section 302.1: The 
following SIC codes are exempt from Section 302.1 of this rule: 
a. Industry Group 366 (Communications Equipment): SIC codes 3661, 3663, and
3669.
b. Industry Group 367 (Electronic Components And Accessories): SIC codes
3677, 3678, and 3679.
c. Industry Group 376 (Guided Missiles And Space Vehicles And Parts): SIC
code 3769.
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d. Industry Group 384 (Surgical, Medical, And Dental Instruments And Supplies):
SIC codes 3841, 3843, 3844, or 3845, and products for internal use in 3842.
The U.S. Department of Labor, Occupational Safety and Health Administration
(OSHA) “Standard Industrial Classification (SIC) Manual” can be found on the
OSHA website at: https://www.osha.gov/data/sic-manual.
103.4 Production processes having clean-room standards equal to or more stringent 
than clean room classification ISO 14644-1:2015 (Class 8) are exempt from 
Section 302.1 of this rule.  
103.5 Low viscosity solvent used to clean an aerospace component if the Federal 
Aviation Authority, the U.S. Department of Defense, or a U.S. Military specification 
designates that the cleanliness of the component is critical to the flight safety of 
a complete aerospace vehicle are exempt from Section 302.1 of this rule. Any 
such solvents shall be listed in a Maricopa County Air Pollution Permit, 
conditioned upon a sufficient demonstration by the user that no compliant 
substitute exists. 
103.6 Aerosol cans, squirt bottles, and other solvent containers intended for handheld 
use shall meet the requirements in Sections 301.1 and 500 of this rule. 
103.7 A Low-VOC Cleaner is subject only to Sections 301.1, 301.2, 302.5(a), 501.5(a), 
and 501.6 of this rule. 
104 
TOTAL CATEGORICAL EXEMPTIONS: This rule does not apply to: 
104.1 A solvent cleaning operation that is subject to or specifically exempted by an 
EPA State Implementation Plan (SIP) approved version of another rule within the 
MCAPCR. 
104.2 Janitorial cleaning. 
104.3 Testing for surface cleanliness or the cleaning of laboratory equipment at the 
laboratory. 
104.4 A cleaning-solvent that meets any of the following: 
a. Is composed of at least 98% water by either weight or volume; or
b. Contains only water and material which is a dry solid before mixing with
water; or
c. Has a VOC content not exceeding 20 grams per liter (0.17 lb/gal).
104.5 All operations regulated by National Emission Standards for Perchloroethylene 
for Dry Cleaning Facilities (40 CFR 63, Subpart M). 
104.6 Operations involving the cleanup of coating-application equipment that are 
subject to or specifically exempted by an EPA SIP-approved version of another 
source-specific rule within the MCAPCR. Examples include Rule 336 (Surface 
Coating Operations and Industrial Adhesive Application Processes), Rule 342 
(Coating Wood Furniture and Fixtures), and Rule 346 (Coating Wood Millwork). 
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SECTION 200 – DEFINITIONS: For the purpose of this rule, the following definitions
shall apply, in addition to those definitions found in Rule 100 (General Provisions and 
Definitions) of these rules. In the event of any inconsistency between any of the MCAPCR, the 
definitions in this rule take precedence.  
201 
AGITATION, AGITATED: A means or state that moves cleaning liquid continuously back 
and forth, or up and down. This includes such motion created by sound waves, and to 
the splashing of a rinse stream operated at a pressure that creates a trajectory 
exceeding 2 feet along the horizontal plane intersecting the nozzle when the nozzle is at 
a 45° angle above the plane. Liquid motion incidental to a continuous entrance or 
withdrawal of objects undergoing cleaning is not agitation. 
202 
BATCH CLEANING MACHINE: A solvent cleaning machine in which individual parts or a 
set of parts move through the entire cleaning cycle before new parts are introduced into 
the solvent cleaning machine. A solvent cleaning machine, such as a ferris wheel or a 
cross-rod degreaser, that cleans multiple batch loads simultaneously and is manually 
loaded, is a batch cleaning machine. 
203 
BLASTING/MISTING WITH SOLVENT: Cleaning with an applicator that propels 
cleaning-solvent through the air or atomizes the solvent into mist and/or droplets. 
204 
CABINET STYLE CLEANING MACHINE: A solvent cleaning machine typically similar in 
design to domestic dishwashers that are completely enclosed except for optional stack 
and have their own reservoir and sump. 
205 
CARRY-OUT: Solvent carried out of a cleaning machine along with a part being 
removed from the cleaning machine. The solvent may exist as a liquid coating the part 
or the part’s hanger, or as a liquid entrapped in cavities and irregular surfaces or 
entrapped by capillary action within or on the part. 
206 
CLEANING-SOLVENT: Solvent used for cleaning that contains more than 2.0% VOC by 
weight and more than 20 grams of VOC per liter (0.17 lb/gal). 
207 
CONFORMING SOLVENT: A cleaning-solvent having a total VOC vapor pressure at 68° F 
(20° C) not exceeding 1 millimeter of mercury column (mm Hg). 
208 
DIP TANK: A container holding solvent used for dipping or coating an object. An object 
may be immersed in a dip tank, or it may be suspended in a vapor coming from the tank. 
209 
DRY SOLID: Any substance that appears and feels dry. Evaporating solids, all of which 
have a strong odor, are not included. 
210 
EMISSION CONTROL SYSTEM (ECS): A system, approved in writing by the Control 
Officer, to reduce emissions of volatile organic compounds. Such a system consists of 
an emissions collection system and an emissions processing subsystem. 
211 
FILTRATION DEVICE: A filter composed of porous material (i.e., canvas bag) which 
collects and removes contaminants from solvent. 
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212 
FLUSHING: Introducing cleaning-solvent directly into the internal space(s) of an object 
or assembly using a hose or pipe. Rinsing the outside of an object or assembly and 
swishing an object or assembly in cleaning-solvent are not considered flushing with 
solvent. Such activities must comply with Section 301.3 of this rule. 
213 
FREEBOARD HEIGHT: 
213.1 Batch Cleaning Machine: The vertical distance from the solvent/air interface to 
the least elevated point of the top-rim when the cover is open or removed, 
measured during idling mode. 
213.2 In-Line Cleaning Machine: The vertical distance from the solvent/air interface to 
the lowest entry/exit point, measured during idling mode. 
214 
FREEBOARD RATIO: The freeboard height divided by the smaller of either the length 
or width of the solvent cleaning machine. 
215 
FULLY SUBMERGED: Any material or object which is maintained below the surface of 
the solvent with no portions exposed to the ambient air. 
216 
HEATED SOLVENT: Any cleaning-solvent which is heated by a device to a temperature 
exceeding 120° F (49° C). 
217 
IMPERVIOUS: Neither absorbing, adsorbing, nor allowing penetration through, by liquid 
or vapors. 
218 
IN-LINE CLEANING MACHINE: A solvent cleaning machine that uses an automated 
handling system, typically a conveyor or automated arm(s), to automatically provide a 
continuous supply of items to be cleaned. The cleaned item leaves by a route different 
from its entry route. 
219 
JANITORIAL CLEANING: The cleaning of building or facility components to keep work 
areas in clean condition. Building or facility components include, but are not limited to, 
floors, ceilings, walls, windows, doors, stairs, bathrooms, furnishings, textiles, wash 
rags, uniforms, and exterior surfaces of office equipment. 
220 
LEAK: A visible cleaning-solvent liquid leak at a rate of three or more drops per minute, 
or a puddle greater than one square inch. 
221 
LOW-VOC CLEANER: Any solution or homogeneous suspension that, as used, contains 
less than 25 grams of VOC per liter of material (0.21 lb VOC/gal) or is at least 95% water 
by weight or volume as determined by an applicable test method in Section 503 of this 
rule. 
222 
MAKE-UP SOLVENT: A cleaning-solvent that replaces solvent lost through evaporation 
or other means, and that is added to the solvent remaining in a cleaning machine to 
bring solvent quantity to the desired level. 
223 
NON-CONFORMING SOLVENT: A cleaning-solvent having a total VOC vapor pressure at 
68° F (20° C) exceeding 1 millimeter of mercury column (mm Hg). 
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224 
NON-VAPOR CLEANING MACHINE: Any liquid container and ancillary equipment 
designed to clean surfaces and/or remove surface contaminants using cleaning-
solvents at temperatures that do not exceed the solvent boiling point. 
225 
PARTS PER MILLION BY VOLUME DRY (PPMVD): A unit of proportion used to express 
concentration that is corrected to a dry basis. 
226 
REFRIGERATED FREEBOARD CHILLER: A control device which is mounted above any 
cooling-water jacket or primary condenser coils, consisting of secondary coils which 
carry a refrigerant to provide a chilled air blanket above the solvent vapor/air interface 
to reduce emissions from the cleaning machine bath. 
227 
REMOTE RESERVOIR CLEANING MACHINE: Any non-vapor cleaning machine in which 
the reservoir for storing the cleaning-solvent is completely separated by impervious 
surfaces from the sink or basin where cleaning is performed, except for a connecting 
tube or passage through which solvent returns to the reservoir when cleaning is 
stopped. 
228 
SEALED SYSTEM: An Air-tight or Airless Cleaning System that is operated and equipped 
pursuant to Section 302.1(c) of this rule. 
229 
SMALL CLEANER: A cleaning machine that has a liquid surface area of 1 square foot 
(0.09 square meters) or less or has a maximum capacity of one gallon (3.79 liters) or 
less. 
230 
SOLVENT: For the purpose of this rule, any VOC-containing liquid or vapor which is used 
to dissolve, clean, strip, or remove impurities, coatings, contaminants, or films from 
surfaces or from internal spaces and voids.  
231 
SOLVENT/AIR INTERFACE: 
231.1 Non-Vapor Cleaner: The location of contact between the liquid solvent and the 
air. 
231.2 Vapor Cleaner: The location of contact between the concentrated layer of 
solvent vapor and the air. 
232 
SOLVENT/AIR INTERFACE AREA: 
232.1 Non-Vapor Cleaner: 
a. With Included/Integral Reservoir: The surface area of liquid cleaning-solvent
that is exposed to the air.
b. With Remote Reservoir: The surface area of the solvent sink or work area.
232.2 Vapor Cleaner: The area of the horizontal plane that is located halfway between 
the highest and lowest points of the primary condenser coils and which contacts 
the interior walls of the cleaning machine. 
233 
TOTAL VOC VAPOR PRESSURE (VOC COMPOSITE PARTIAL PRESSURE): Within a 
solution or homogenous mixture, it is the sum of the partial pressures of all those 
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components that are defined as VOCs, calculated according to the formula in Section 
503.1(f) of this rule. 
234 
VAPOR CLEANING MACHINE: A batch or in-line cleaning machine in which solvent-
vapor from boiling cleaning-solvent is utilized for cleaning an object. 
235 
VAPOR LEVEL CONTROL SYSTEM: A combination of a coolant sensing system and a 
vapor sensing system consisting of the following three sets of features: 
235.1 A condenser flow switch and thermostat which shuts off the sump heat if either 
the condenser coolant stops circulating or becomes warmer than 85° F (29° C); 
and 
235.2 A manually-reset safety switch which turns off the sump heater if the 
temperature sensor senses that the temperature is rising above the designed 
operating level at the vapor/air interface; and 
235.3 A manually-reset switch which turns off the spray-system pump if the level of the 
vapor/air interface drops more than 4 inches (10 cm). 
236 
VOC CONTENT OF MATERIAL: The weight of VOC per volume of material, as calculated 
according to the formula in Section 503.1(g) of this rule. 
237 
WIPE CLEANING: A cleaning method of removing contaminants from a surface by 
physically rubbing or automatically rubbing with a porous or absorbent material, such as 
a rag, paper, sponge, or cotton swab, moistened with a solvent. 
SECTION 300 – STANDARDS 
301 
GENERAL REQUIREMENTS FOR SOLVENT CLEANING OPERATIONS: An owner or 
operator subject to this rule shall comply with all of the following: 
301.1 Solvent Handling Requirements: All cleaning-solvent, including solvent soaked 
materials, shall be kept in closed, leak free, impervious containers that are 
opened only when adding or removing material. 
a. Porous or absorbent materials used for wipe cleaning shall be stored in
closed containers when not in use.
b. Each container shall be clearly labeled with its contents.
c. Wipe up or otherwise remove any cleaning-solvent that escapes from a
container immediately if in accessible areas.
d. For areas where access is not feasible during normal production, remove any
cleaning-solvent that escapes from a container as soon as reasonably
possible.
e. Disposal of waste or surplus solvent shall be done in a manner that does not
promote VOC evaporation, such as, but not limited to, via sewage treatment
works or having the waste hauled off-site in sealed containers.
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301.2 Equipment Requirements for All Cleaning Machines: An owner or operator who 
is operating a cleaning machine to which this rule applies must comply with all of 
the following: 
a. Provide a leak free, impervious container for the solvents and the articles
being cleaned. The VOC-containment portion shall be impervious to VOC-
containing liquid and vapors.
b. No surface of any freeboard required by this rule shall have an opening or
duct through which VOC can escape to the atmosphere, except as controlled
by an ECS, or as required by OSHA.
c. Properly maintain and operate all cleaning machine equipment required by
this rule and any of its emission controls required by this rule.
301.3 Operating Requirements for Cleaning Machines: An owner or operator who 
cleans with cleaning-solvent, other than a Low-VOC Cleaner, must comply with all 
of the following operating requirements for cleaning machines: 
a. Fans: Do not locate nor position comfort fans in such a way as to direct
airflow across the opening of any cleaning machine. This prohibition does not
apply to a totally enclosed cleaning machine that cannot be penetrated by
drafts.
b. Cover: Do not remove any device designed to cover the solvent unless
processing work in the cleaning machine or maintaining the machine.
c. Draining: Drain cleaned parts for at least 15 seconds after cleaning or until
dripping ceases, whichever is later.
d. Spraying: If using a cleaning-solvent spray system,
(1) Use only a continuous, undivided stream (not a fine, atomized, or shower
type spray).
(2) Pressure at the orifice from which the solvent emerges shall not cause
liquid solvent to splash outside of the solvent container.
(3) In an in-line cleaning machine, a shower-type spray is allowed, provided
that the spraying is conducted in a totally confined space that is separated
from the environment.
(4) Provisions for exceptions to Sections 301.3(d)(1), (2), and (3) are provided
for in Section 302.5 of this rule.
e. Agitation: An owner or operator shall not cause agitation of a cleaning-
solvent in a cleaning machine by sparging with air or other gas. Covers shall
be placed over ultrasonic cleaners when the cleaning cycle exceeds 15
seconds.
f.
Porous Material: Do not clean porous or absorbent materials in a cleaning
machine. For the purpose of this rule, porous or absorbent materials include,
but are not limited to, cloth, leather, wood, and rope.
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g. Vent Rates: The ventilation rate at the cleaning machine shall not exceed 65
cfm per square foot of evaporative surface (20 m
3/min./m
2), unless that rate
must be changed to meet a standard specified and certified by a Certified
Safety Professional, a Certified Industrial Hygienist, or a licensed professional
engineer experienced in ventilation, to meet health and safety requirements.
h. Hoist Speed: Limit the vertical speed of mechanical hoists moving parts in
and out of the cleaning machine to a maximum of 2.2 inches per second and
11 ft/min. (3.3 m/min.).
i.
Contamination Prevention: Prevent cross contamination of solvents
regulated by Section 302.1 of this rule with low-VOC cleaners. Use signs,
separated work-areas, or other effective means for this purpose. This
includes cleaning-solvents that are regulated by another source-specific rule
within Maricopa County Rules of Regulation III.
j.
Filtration Devices: If a filtration device (e.g., to remove oils, greases, sludge,
and fine carbon from cleaning-solvent) is inherent in the design of the
cleaning machine, then such filtration device shall be operated in accordance
with the following requirements:
(1) The filtration device shall be operated in accordance with manufacturer’s
specifications.
(2) The filtration device shall be maintained under the protective shelf in the
wash basin, when applicable.
(3) The filtration device shall be fully submerged in cleaning-solvent at all
times during filtration.
(4) When the filtration device is completely saturated and must be removed
from the cleaning machine, the filtration device shall be drained until no
liquid can flow from the filtration device. Draining and drying such
filtration device shall be conducted in a sealed container with no exhaust
to the atmosphere or work area.
(5) After the filtration device is dry, the filtration device shall be stored in a
closed, leak free, impervious container that is legibly labeled with its
contents and that remains covered when not in use. Disposal of the
filtration device shall be done in a manner that inhibits VOC evaporation
and that is in compliance with appropriate/legal methods of disposal.
301.4 Signage Requirements: An owner or operator who uses cleaning-solvent, other 
than Low-VOC Cleaner, in any solvent cleaning machine or dip tank shall provide 
on the machine, or within 3¼ feet (1 meter) of the machine, a permanent, 
conspicuous label or placard which includes, at a minimum, each of the following 
applicable instructions, or its equivalent:  
a. “Keep cover closed when parts are not being handled.” (This is not required
for remote reservoir cleaners.)
b. “Drain parts until they can be removed without dripping.”
c. “Do not blow off parts before they have stopped dripping.”
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d. “Wipe up spills and drips as soon as possible; store used spill rags [or ‘wiping
material’] in covered container.”
e. “Do not clean porous or absorbent materials in this tank.”
f.
For cleaning machines with moving parts such as hoists, pumps, or
conveyors, post: “Operating instructions can be obtained from _______,” listing
a person or place where the instructions are available.
302 
NON-VAPOR CLEANING MACHINE REQUIREMENTS 
302.1 Solvent Specifications for Non-Vapor Cleaning Machines: All cleaning-solvents, 
except Low-VOC Cleaners, used in non-vapor cleaning machines shall comply 
with one of the following requirements: 
a. Conforming Solvent: Use a cleaning-solvent having a total VOC vapor
pressure at 68° F (20° C) not exceeding 1.0 millimeter of mercury column
(mm Hg), as determined by the standards described in Section 500 of this
rule; or
b. ECS: Use an ECS to capture and process VOC emissions in accordance with
Section 304 of this rule; or
c. Sealed System: Use a Sealed System that is an Air-tight or Airless Cleaning
System which is operated according to the manufacturer’s specifications and,
unless otherwise indicated by the manufacturer, meets all of the following
requirements:
(1) Has a door or other pressure-sealing apparatus that is shut during each
cleaning and drying cycle; and
(2) Has a differential pressure gauge that always indicates the pressure in the
sealed chamber when occupied or in active use; and
(3) Any associated pressure relief device(s) shall be so designed and
operated as to prevent liquid cleaning-solvents from draining out.
302.2 Non-Vapor Batch Cleaning Machines: An owner or operator who operates a non-
vapor batch cleaning machine shall comply with the following requirements 
(Low-VOC Cleaners are exempt from this section): 
a. With Remote Reservoir: A batch cleaning machine with remote reservoir,
including cabinet type(s), shall be equipped with all of the following:
(1) A sink-like work area or basin which is sloped sufficiently towards the
drain to prevent pooling of cleaning-solvent.
(2) A single, unimpeded drain opening, or cluster of openings served by a
single drain for the cleaning-solvent to flow from the sink into the
enclosed reservoir. Such opening(s) shall be contained within a
contiguous area not larger than 15.5 square inches (100 cm
2).
(3) Provide a means for drainage of cleaned parts such that the drained
solvent is returned to the cleaning machine.
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b. With Internal Reservoir (Non-Remote): A batch cleaning machine without a
remote reservoir shall be equipped with all of the following:
(1) Have and use an internal drainage rack or other assembly that confines
within the freeboard all cleaning-solvent dripping from parts and returns it
to the hold of the cleaning machine; and
(2) Have an impervious cover which when closed prevents cleaning-solvent
vapors in the cleaning machine from escaping into the air/atmosphere
when not processing work in the cleaning machine.
(a) A cover shall be fitted so that in its closed position the cover is
between the cleaning-solvent and any lip exhaust or other safety vent,
except that such position of cover and venting may be altered by an
operator for valid concerns of flammability established in writing and
certified to by a Certified Safety Professional or a Certified Industrial
Hygienist to meet health and safety requirements.
(b) A cover is not required when an ECS is used in accordance with
Section 304 of this rule.
(3) In the absence of additional applicable freeboard standards, freeboard
height shall be not less than 6 inches (15.2 cm); and
(4) The freeboard zone shall have a permanent, conspicuous mark that
locates the maximum allowable solvent level which conforms to the
applicable freeboard requirements.
c. Cleaning-Solvent that is Heated or Agitated in a Non-Vapor Batch Cleaning
Machine: If a non-vapor batch cleaning machine uses a cleaning-solvent at a
temperature above 120° F (49° C) or agitates the solvent, then comply with
one of the following:
(1) Remote Reservoir Cleaning Machines: For a remote reservoir cleaning
machine, comply with Section 302.2(a) of this rule and one of the
following:
(a) Use a stopper in the drain whenever the sink or cabinet is empty of
solvent and nothing is being handled in the sink; or
(b) Cover the sink or cabinet whenever the sink or cabinet is empty of
solvent and nothing is being handled in the sink.
(2) Internal Reservoir Cleaning Machines: For an internal reservoir cleaning
machine, comply with Section 302.2(b) of this rule and one of the
following:
(a) Water Cover: A floating layer of water (insoluble in the solvent) at least
1 inch thick, and a freeboard at least 6 inches above the top of the
solvent shall be present; or
(b) Freeboard and Cover:
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(i) The basin shall have a freeboard ratio of 0.75 or greater and an
impervious cover shall cover the basin whenever work is not being
processed; and
(ii) If a non-conforming solvent is used, the cover shall be of a sliding
or rolling type which is designed to easily open and close in a
horizontal plane without disturbing the vapor zone.
(3) Cabinet Style: Keep a cabinet-style cleaning machine that contains
cleaning-solvent closed at all times, except when introducing or removing
work from the machine. If blasting or misting with cleaning-solvent, also
conform to the applicable requirements of Section 302.5 of this rule.
d. ECS Alternative: In lieu of meeting the requirements in Sections 302.2(a),
302.2(b), and/or 302.2(c) of this rule, an owner or operator may comply by
using an ECS that is approved in writing by the Control Officer and meets the
requirements in Section 304.
302.3 Non-Vapor In-Line Cleaning Machines: An owner or operator who operates a 
non-vapor in-line cleaning machine using cleaning-solvent shall comply with 
Sections 302.3(a) through 302.3(e), or Section 302.3(f): 
a. Carry-Out Prevention: Equip the cleaning machine with either a drying tunnel
or another means, such as a rotating basket, sufficient to prevent cleaned
parts from carrying out cleaning-solvent liquid or vapor.
b. Enclosed Design: An in-line cleaning machine shall be fully enclosed except
for entrance and exit portals.
c. Cover: During shutdown hours or if the cleaning machine is idle for more than
30 minutes, a cover shall be used to close the entrance and exit and any
opening greater than 16 square inches (104 cm
2).
d. Minimized Openings: Entrances and exits should silhouette workloads so
that the average clearance between parts and the edge of the cleaning
machine opening is either less than four inches (10 cm), or less than 10% of
the width of the opening.
e. Freeboard Ratio: The machine shall have a freeboard ratio greater than or
equal to 0.75.
f.
ECS Alternative: In lieu of meeting the requirements in Sections 302.3(a)
through Section 302.3(e) of this rule, an owner or operator may comply by
using an ECS that is approved in writing by the Control Officer and meets the
requirements in Section 304.
302.4 Non-Conforming Solvent used in a Non-Vapor Batch or In-Line Cleaning 
Machine: A non-conforming solvent may be used in operations to which this rule 
applies, if at least one of the following is met: 
a. ECS or Sealed System: The emissions from the operation shall be controlled
by an ECS per Section 302.1(b) of this rule or by a Sealed System per Section
302.1(c) of this rule; or
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b. Partial Exemption: The operation is exempted per Sections 103.1 and/or
103.2 of this rule; or
c. Non-Vapor Batch Cleaning Machine: The operation is both exempted per
Section 103.3 of this rule and complies with Section 302.2(a) or 302.2(b) of
this rule, as applicable; or
d. Non-Vapor In-Line Cleaning Machine: The operation is both exempted per
Section 103.3 of the rule and complies with Section 302.3 of this rule.
302.5 Special Non-Vapor Cleaning Situations: 
a. Blasting/Misting with Conforming Solvent or Low-VOC Cleaner: An owner or
operator blasting or misting with conforming solvent or a low-VOC cleaner
shall operate and equip the device(s) as follows:
(1) Equipment: The device shall have internal drainage, a reservoir or sump,
and a completely enclosed cleaning chamber, designed to prevent any
perceptible liquid from emerging from the device; and
(2) Operation: The device shall be operated such that there is no perceptible
leakage from the device except for incidental drops from drained, removed
parts.
b. Blasting/Misting with Non-Conforming Solvent: An owner or operator shall
use a Sealed System pursuant to Section 302.1(c) of this rule for all blasting
or misting with a non-conforming solvent.
c. High Pressure Flushing: Cleaning systems using cleaning-solvent that
emerges from an object undergoing flushing with a visible mist shall comply
as follows:
(1) Conforming Solvent: For conforming solvent, use a containment system
that is designed to prevent any perceptible cleaning-solvent liquid from
becoming airborne outside the containment system, such as a completely
enclosed chamber.
(2) Non-Conforming Solvent: Use a Sealed System pursuant to Section
302.1(c) of this rule for non-conforming solvent.
d. ECS Alternative: In lieu of meeting the requirements in Sections 302.5(a)
and/or Section 302.5(b) of this rule, an owner or operator may comply by
using an ECS that is approved in writing by the Control Officer and meets the
requirements in Section 304.
303 
VAPOR CLEANING MACHINE REQUIREMENTS: 
303.1 General Equipment Requirements for Vapor Cleaning Machines: An owner or 
operator of a batch vapor cleaning machine or an in-line vapor cleaning machine 
shall ensure it is equipped with all of the following: 
a. A Vapor Level Control System.
b. Freeboard Ratio: A freeboard ratio that is greater than or equal to 0.75.
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c. Refrigeration or ECS: Batch vapor cleaning machines or in-line vapor cleaning
machines having an evaporative surface area equal to or greater than 10.75
ft² (1.0 m²), installed or subject to major modification after November 1, 1999,
or having average monthly VOC emissions exceeding 31 pounds VOC per
square foot of solvent surface area shall comply with one of the following
subsections:
(1) A refrigerated freeboard chiller where the chilled air blanket temperature
measured in degrees Fahrenheit at the coldest point on the vertical axis
through the horizontal center of the vapor/air interface shall be either no
greater than 30% of the initial boiling point of the solvent, measured in
degrees Fahrenheit, or no greater than 40.0° F (4.4° C), whichever is lower;
or
(2) A refrigerated condenser coil (in place of an unrefrigerated coil) having a
minimum cooling capacity of 100% of the boiling-sump heat input rate and
where the chilled air blanket temperature measured in degrees Fahrenheit
at the coldest point on the vertical axis through the horizontal center of the
vapor/air interface shall be either no greater than 30% of the initial boiling
point of the solvent, measured in degrees Fahrenheit, or no greater than
40.0° F (4.4° C), whichever is lower; or
(3) An ECS operated in accordance with Section 304 of this rule.
d. Primary Condenser: A primary condenser that maintains an exit temperature
not exceeding 85° F (29° C). Alternatively, a batch vapor cleaning machine
may be equipped pursuant to Section 303.1(c)(2).
e. Water Separator: Water should not be visually detectable in the VOC-
containing solvent exiting the water separator.
303.2 Batch-Loaded Vapor Cleaning Machines: An owner or operator shall ensure a 
batch-loaded vapor cleaning machine meets the requirements in Section 303.1 
and all of the following: 
a. Cover: Equipped with an impermeable cover that is a sliding, rolling, fanning,
or guillotine (bi-parting) type which is designed to easily open and close
without disturbing the vapor zone.
b. Lip Exhausts: Batch-loaded vapor cleaning machines with lip exhausts shall
be controlled by an ECS.
c. Workloads:
(1) A workload shall not occupy more than half of the cleaning machine’s
open-top area.
(2) The workload shall not be so massive that the vapor level drops more than
4 inches (10 cm), when the workload is removed from the vapor zone.
(3) The workload shall not be sprayed with cleaning-solvent above the
vapor/air interface level.
d. Carry-Out: Minimize cleaning-solvent carry-out by the following measures:
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(1) Orient the items being cleaned in such a way that the items drain easily
after cleaning.
(2) Degrease the workload in the vapor zone at least 30 seconds or until
condensation ceases.
(3) For manual loading/unloading, tip out any pools of solvent on the cleaned
parts before removal.
(4) Allow parts to dry within the batch vapor cleaning machine until visually
dry.
e. Startup and Shutdown: The following sequence shall be used for startup and
shutdown:
(1) When starting the batch vapor cleaning machine, the cooling system shall
be turned on before, or simultaneously with, the sump heater.
(2) When shutting down the batch vapor cleaning machine, the sump heater
shall be turned off before, or simultaneously with, the cooling system.
f.
Blasting: Blasting in a batch vapor cleaning machine shall be done within a
Sealed System or be controlled by an ECS.
g. Records: Maintain records pursuant to Section 501 of this rule.
303.3 In-Line Vapor Cleaning Machines: An owner or operator shall ensure an in-line 
vapor cleaning machine meets the requirements in Section 303.1 and all of the 
following: 
a. Cover: Within 10 minutes of turning off the solvent heating system, cover the
entrance and exit and any opening greater than 16 square inches (104 cm2).
b. Workloads: The average clearance between parts and the edge of the in-line
vapor cleaning machine opening is either less than 4 inches (10 cm) or less
than 10% of the width of the opening.
c. Carry-Out: Equip the in-line vapor cleaning machine with either a drying tunnel
or another means, such as a rotating basket, sufficient to prevent cleaned
parts from carrying out cleaning-solvent liquid or vapor.
d. Startup and Shutdown: The following sequences shall be used for startup and
shutdown:
(1) When starting the in-line vapor cleaning machine, the cooling system shall
be turned on before, or simultaneously with, the sump heater.
(2) When shutting down the in-line vapor cleaning machine, the sump heater
shall be turned off before, or simultaneously with, the cooling system.
e. Records: Maintain records pursuant to Section 501 of this rule.
304 
EMISSION CONTROL SYSTEM (ECS) REQUIREMENTS: 
304.1 ECS Control Efficiencies: To meet the requirements pursuant to Section 302.1(b) 
of this rule, an ECS shall comply with one of the following: 
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a. Overall ECS Efficiency: Operate an ECS that has an 85% overall VOC capture
and control efficiency, determined by applicable provisions in Section
503.1(c) of this rule; or
b. Alternative for Very Dilute Input: For VOC input-concentrations of less than
100 ppmvd (as propane) at the inlet of the ECS, the control efficiency is
satisfied if the VOC outlet concentration is less than or equal to 10 ppmvd (as
propane), determined by applicable provisions in Section 503.1(d) of this rule.
304.2 Operation and Maintenance (O&M) Plan Required for ECS: 
a. An owner or operator shall provide and maintain (an) O&M Plan(s) for any
ECS and any ECS monitoring devices used pursuant to this rule or to a
Maricopa County Air Quality Permit.
b. The owner or operator shall submit to the Control Officer for approval the
O&M Plan(s) of each ECS and each ECS monitoring device used pursuant to
this rule.
c. The owner or operator shall comply with all identified actions and schedules
provided in each O&M Plan.
304.3 Providing and Maintaining ECS Monitoring Devices: An owner or operator 
incinerating, adsorbing, or otherwise processing VOC emissions pursuant to this 
rule shall provide, properly install and maintain in calibration, in good working 
order devices described in the facility’s O&M Plan that indicate temperatures, 
pressures, rates of flow, or other operating conditions necessary to determine if 
the ECS is functioning properly and is properly maintained. Records shall be kept 
pursuant to Section 502 of this rule which demonstrate that the ECS meets the 
overall control standard required by Section 304.1 of this rule and is operated in 
accordance with the equipment manufacturer's specifications. 
304.4 O&M Plan Responsibility: An owner or operator of a facility that is required to 
have an O&M Plan pursuant to Section 304.2 of this rule must fully comply with 
all O&M Plans that the owner or operator has submitted for approval, but which 
have not yet been approved, unless notified otherwise by the Control Officer in 
writing. 
304.5 O&M Plan Contents for an ECS: An O&M Plan for any ECS including any ECS 
monitoring devices shall include all of the following information: 
a. ECS equipment manufacturer;
b. ECS equipment model;
c. ECS equipment identification number or identifier that owner or operator
subject to this rule assigns to such ECS equipment when manufacturer’s
equipment identification number is unknown; and
d. Information required by Sections 502 and 503 of this rule.
SECTION 400 – ADMINISTRATIVE REQUIREMENTS 
401 
COMPLIANCE SCHEDULE: 
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401.1 ECS Installation at New Sources: For sources that commence construction after 
[revision date], compliance with the ECS requirements shall be achieved upon 
source startup. 
401.2 New Low-VOC Cleaner Limit: Upon adoption of this rule, an owner or operator 
using a low-VOC cleaner to comply with this rule shall discontinue purchase of 
materials that are non-compliant with the new low-VOC cleaner limit of this rule. 
The owner or operator may continue to use supplies of non-compliant low-VOC 
cleaner materials purchased prior to [date] until [six-month deadline date]. 
SECTION 500 – MONITORING AND RECORDS 
501 
RECORDKEEPING AND REPORTING: An owner or operator subject to this rule shall 
comply with the following recordkeeping requirements: 
501.1 Records shall be retained for a period of five years. 
501.2 Records shall be made available to the Control Officer no later than five business 
days upon verbal or written request. 
501.3 Records shall be made available to the Control Officer upon request by members 
of the public using the County’s public records request process. 
501.4 Records shall be kept on site at all times in a consistent and complete manner. 
501.5 Current List: 
a. Maintain a current list of cleaning-solvents; state the VOC content of each in
pounds VOC per gallon of material or grams per liter of material.
b. A facility using any cleaning-solvent subject to the vapor-pressure limits of
Section 302.1(a) of this rule shall have on site the written value of the total
VOC vapor-pressure of each such solvent, in one of the following forms:
(1) A manufacturer’s technical data sheet;
(2) A manufacturer’s safety data sheet (MSDS); or
(3) Actual test results.
501.6 Usage Records: 
a. Monthly: Records of the amount of cleaning-solvent purchased or used shall
be totaled by the end of the month for the previous month. Show the type and
amount of each make-up solvent and all other cleaning-solvent to which this
rule is applicable.
b. Annually:
(1) Certain Concentrates: Use of concentrate that is used only in the
formulation of Low-VOC Cleaner shall be updated at least annually.
(2) Low-VOC Cleaner: An owner or operator need not keep a record of a
cleaning substance that is made by diluting a concentrate with water or
non-precursor organic compound(s) to a level that qualifies as a Low-VOC
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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Cleaner if records of the concentrate usage are kept in accordance with 
this rule. 
c. Grouping by VOC Content: For purposes of recording usage, an owner or
operator may give cleaning-solvents of similar VOC content a single group-
name, distinct from any product names in the group. The total usage of all the
products in that group is then recorded under just one name. In such a case,
the owner or operator must also keep a separate list that identifies the
product names of the particular cleaning-solvents included under the group
name. To the group name shall be assigned the highest VOC content among
the members of that group, rounded to the nearest tenth of a pound of VOC
per gallon of material, or to the nearest gram VOC per liter of material.
501.7 Records of Disposal: Maintain records of the type, amount, and method of 
disposing of waste solvent. Records of legal disposal include but are not limited 
to shipping papers or quantity discharged to sewage treatment works. 
502 
ECS RECORDKEEPING REQUIREMENTS: An owner or operator shall maintain all of the 
following records in accordance with an approved O&M Plan for any required ECS: 
502.1 On each day a required ECS is used at a facility pursuant to this rule, the owner or 
operator shall make a permanent record of the key system operating parameters 
as required by the O&M Plan which may include the following, when applicable: 
a. Flow rates;
b. Pressure drops;
c. Temperature; or
d. Other operating conditions necessary to determine if the approved ECS is
functioning properly.
502.2 An explanation shall be recorded for periods of time an approved ECS is not 
operating. 
502.3 For each day or period the O&M Plan requires maintenance, the owner or 
operator shall make a permanent record of the maintenance actions taken within 
3 business days of the maintenance completion. 
502.4 Corrective action taken, if any. 
502.5 An explanation shall be entered for scheduled maintenance that is not performed 
during the period designated for it in the O&M Plan. 
502.6 Other Records Required when Complying via ECS: An owner or operator using an 
ECS pursuant to this rule shall maintain, in addition to the records required by 
Section 501.5 of this rule, monthly documentation showing the VOC content of 
the solvent material and the amount added for makeup. 
503 
COMPLIANCE DETERMINATION AND TEST METHODS: 
503.1 Compliance Determination: 
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a. VOC Content: The VOC content of solutions, dispersions, emulsions, and
conforming solvents shall be determined by one of the following methods:
(1) South Coast Air Quality Management District (SCAQMD) Method 313-91
as referenced in Section 503.3(a) of this rule; or
(2) Bay Area Air Quality Management District (BAAQMD) Method 31 as
referenced in Section 503.3(b) of this rule.
b. Vapor Pressure: Determination of the total VOC vapor-pressure (VOC
composite partial-pressure) in a cleaning solution shall be performed as
follows:
(1) For solutions known to be nearly or exactly 100% VOC, vapor pressure
shall be determined by ASTM D2879-97as referenced in Section 503.4(a)
of this rule; or
(2) For solutions for which is known the exact quantity and chemical makeup
of each evaporating component that is not a VOC, ASTM D2879-97
(referencing Section 503.4(a) of this rule) shall be used (to determine the
gross composite vapor pressure) in conjunction with calculations using
the vapor pressure formula in Section 503.1(f) of this rule.
(3) When a solution’s exact species and proportions are known for all
ingredients, the Control Officer may use the formula in Section 503.1(f) of
this rule in conjunction with standard reference texts or databases that
provide the vapor pressure value of each constituent, or a combination of
formula use and actual testing on real constituents (referencing Section
503.4(a) of this rule).
c. ECS Efficiency: An owner or operator that complies with Section 304.1(a) of
this rule using an ECS shall demonstrate compliance using the following
methods and equations:
(1) Overall ECS Efficiency shall be determined using the following equation:
EffO = (EffCo x EffCa) / 100 
where, 
EffO  = Overall ECS efficiency expressed as a percentage; and 
EffCo  = ECS control efficiency expressed as a percentage; and 
EffCa  = ECS capture efficiency expressed as a percentage. 
(2) The ECS control efficiency shall be determined by measuring the VOC
content of gaseous emissions entering and exiting the ECS using EPA
Method 18, referenced in Section 503.2(e) of this rule, or EPA Methods 25,
25A, and 25B, referenced in Section 503.2(f) of this rule.
(3) The ECS capture efficiency shall be determined either by the methods in
Section 503.2(g) of this rule (EPA Methods 204, 204A, 204B, 204C, 204D,
204E, and 204F) or by using mass balance calculation methods in concert
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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with the methods in Section 503.2(b) of this rule (EPA Methods 2, 2A, 2C, 
and 2D), and EPA guidance document, “Guidelines for Determining 
Capture Efficiency”, January 9, 1995. 
d. Alternative for Very Dilute Input: An owner or operator that complies with
Section 304.1(b) of this rule shall demonstrate compliance by using EPA
Method 25A referred to in Section 503.2(f) of this rule.
e. Temperature Measurement: Temperature measurements to determine if a
cleaning machine contains a “heated solvent” shall be done with an
instrument having an accuracy and precision of within 1 degree Fahrenheit.
f.
Formula for VOC Composite Partial Pressure (Equivalent to: Total VOC Vapor
Pressure): The VOC composite partial pressure shall be calculated by the
following equation:
(
)(
)
∑
∑
∑
=
=
=
+
+
=
m
j
n
i
i
i
e
e
w
n
i
i
i
i
c
M
W
M
W
W
M
VP
W
PP
1
1
1
18
where, 
Wi = Weight of the “i”th VOC compound in grams 
Ww = Weight of water in grams 
We = Weight of the “j”th non-precursor organic compound in 
grams 
Mi = Molecular weight of the “i”th VOC compound in grams per 
gram mole 
Me = Molecular weight of the “j”th non-precursor compound 
PPc = VOC composite partial pressure at 20°C in mm mercury (Hg) 
VPi = Vapor pressure of the “i”th VOC compound at 20°C in mm 
Hg 
18 = Weight of one gram-mole of water 
n = Total number of different (dissolved) VOCs 
m = Total number of different (dissolved) non-precursor organic 
compounds 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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g. Formula for VOC Content of Solvent: The VOC content of solvent shall be
calculated by the following equation:
VOC CONTENT OF MATERIAL as a percent =
W
W
W
m
s
w
es
W
−
−
 X 100% 
Using consistently either pounds or grams in the calculations, where: 
Ws 
= 
Weight of volatile material in pounds (or grams), including 
water, non-precursor organic compounds, and dissolved 
vapors 
Ww 
= 
Weight of water in pounds (or grams) 
Wes 
= 
Total weight of non-precursor organic compounds in pounds 
(or grams) 
Wm 
= 
Weight of total material in pounds (or grams) 
VOC CONTENT OF MATERIAL in pounds per gallon (lbs/gal) or grams per liter (g/l) = 
W
W
W
m
s
w
es
V
−
−
Using consistently either English or metric measures in the calculations, where: 
Ws 
= Weight of all volatile material in pounds (or grams) including 
VOC, water, non-precursor organic compounds and dissolved 
vapors 
Ww 
=  Weight of water in pounds (or grams) 
Wes 
=  Weight of all non-precursor organic compounds in pounds (or 
grams) 
Vm 
=  Volume of total material in gallons (or liters) 
503.2 EPA-Approved Test Methods Incorporated by Reference: The following test 
methods are approved for use for the purpose of determining compliance with 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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this rule. The test methods are incorporated by reference in Appendix G of the 
MCAPCR. Alternative EPA-approved test methods may be used upon prior written 
approval from the Control Officer. When more than one test method is permitted 
for the same determination, an exceedance under any method will constitute a 
violation.  
a. EPA Methods 1 (“Sample and Velocity Traverses for Stationary Sources”) and
1A (“Sample and Velocity Traverses for Stationary Sources with Small Stacks
or Ducts”) (40 CFR 60, Appendix A-1).
b. EPA Methods 2 (“Determination of Stack Gas Velocity and Volumetric Flow
Rate”), 2A (“Direct Measurement of Gas Volume Through Pipes and Small
Ducts”), 2C (“Determination of Stack Gas Velocity and Volumetric Flow rate in
Small Stacks or Ducts”), and 2D (“Measurement of Gas volumetric Flow Rates
in Small Pipes and Ducts”) (40 CFR 60, Appendix A-1).
c. EPA Methods 3 (“Gas Analysis for the Determination of Dry Molecular
Weight”), 3A (“Determination of Oxygen and Carbon Dioxide Concentrations in
Emissions From Stationary Sources (Instrumental Analyzer Procedure”), 3B
(“Gas Analysis for the Determination of Emission Rate Correction Factor or
Excess Air”), and 3C (“Determination of Carbon Dioxide, Methane, Nitrogen,
and Oxygen from Stationary Sources”) (40 CFR 60, Appendix A-2).
d. EPA Method 4 (“Determination of Moisture Content in Stack Gases”) (40 CFR
60, Appendix A-3).
e. EPA Method 18 (“Measurement of Gaseous Organic Compound Emissions by
Gas Chromatography”) (40 CFR 60, Appendix A-6).
f.
EPA Methods 25 (“Determination of Total Gaseous Non-Methane Organic
Emissions as Carbon”), 25A (“Determination of Total Gaseous Organic
Concentration Using a Flame Ionization Analyzer”), and 25B (“Determination
of Total Gaseous Organic Concentration Using a Nondispersive Infrared
Analyzer”) (40 CFR 60, Appendix A-7).
g. EPA Methods 204 (“Criteria for and Verification of a Permanent or Temporary
Total Enclosure”), 204A (“Volatile Organic Compounds Content in Liquid Input
Stream”), 204B (“Volatile Organic Compound Emissions in Captured Stream”),
204C (“Volatile Organic Compound Emissions in Captured Stream (Dilution
Technique)”), 204D (“Volatile Organic Compound Emissions in Uncaptured
Stream from Temporary Total Enclosure”), 204E (“Volatile Organic Compound
Emissions in Uncaptured Stream from Building Enclosure”), and 204F
(“Volatile Organic Compounds Content in Liquid Input Stream (Distillation
Approach)”) (40 CFR 51, Appendix M) .
h. EPA guidance document, “Guidelines for Determining Capture Efficiency”,
January 9, 1995.
503.3 EPA-Approved California Air Resources Board (CARB) Test Methods 
Incorporated by Reference: 
a. SCAQMD Method 313-91 (February 1997), “Determination of Volatile Organic
Compounds (VOC) by Gas Chromatography/Mass Spectrometry (GC/MS)”.
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b. BAAQMD Method 31 (May 18, 2005), “Determination of Volatile Organic
Compounds in Paint Strippers, Solvent Cleaners, and Low Solids Coatings”.
503.4 EPA-Approved American Society for Testing and Materials (ASTM) Standard 
Incorporated by Reference: 
a. ASTM D2879-97, “Test Method for Vapor Pressure-Temperature Relationship
and Initial Decomposition Temperature of Liquids by Isoteniscope”.
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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1 
BOARD OF HEALTH SPECIAL MEETING MINUTES 
Monday, August 28, 2023 | 4:00-5:00 pm 
VIRTUAL 
ITEM 
TOPIC/ACTION 
PRESENTER 
1. 
CALL TO ORDER: The virtual meeting was called to order at 4:04 pm 
A.
Roll Call
Members Present: Debra Baldauff, Paula Banahan, Matthew Farber,
Supervisor Bill Gates, Cynthia Hardy, Robert MacMillan, Veronica Oros,
Lorenzo Sierra, Paul Stander
Ex-Officio: Marcy Flanagan
Members Absent: Joanne Osborne
•
There was a quorum (6) of members.
B. Call to the public: There were no requests to speak.
President 
MacMillan 
2. 
Appointments to the Board of Health  
Ms. Flanagan welcomed the newest members of the Board of Health whose 
appointments were approved by the Board of Supervisors. 
•
Lorenzo Sierra, representing District 5. Term of service is August 9, 2023
through December 31, 2024.
•
Veronica Oros, member-at-large. Term of service is August 23, 2023
through December 31, 2024.
•
Cynthia Hardy, representing District 1. Term of service is August 23, 2023
through December 31, 2025.
Marcy 
Flanagan 
3. 
Continuance of Officer Term and Postponement of Elections (vote to continue at 
next board meeting) 
President MacMillan asked the Board for a motion for the continuation of 
elections, and continuance of officer terms, moving the agenda item to the next 
Board of Health meeting. 
•
Motion: Lorenzo Sierra
•
Second: Dr. Paul Stander
•
Motion status: Approved unanimously
President 
MacMillan 
4. 
Environmental Services Department Fee Waiver Applications 
A. Request for Board of Health approval of (25) fee waiver applications
Fee Waiver Staff Report and Board of Health Fee Waiver Application Summary
Sheet
Robert 
Stratman 
Return to list of attachments
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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MARICOPA COUNTY BOARD OF HEALTH 
AUGUST 28, 2023 – MEETING MINUTES 
2 
This quarter the department reviewed twenty-five (25) fee waiver applications. 
Of the applications reviewed, staff determined that all meet the criteria outlined 
in the Maricopa County Environmental Health Code.  
 
As a reminder, only an operator of a charitable nonprofit establishment which 
operates to provide relief predominantly for the poor, distressed, or 
underprivileged may apply to the Board of Health for a waiver of a permit fee. A 
waiver of a permit fee may be granted only to the operator of an establishment, 
which maintains a current 501(c)(3) tax-exempt designation from the Internal 
Revenue Service and who demonstrates to the Board of Health that payment 
of said fee will cause financial hardship. 
Applications for waivers of Temporary Food Establishment fees will be 
processed on a first come, first served basis in accordance with Chapter I, 
Regulation 5 a. of the Environmental Health Code. The Department shall only 
present a maximum of twenty-five (25) of such applications per event to the 
Board of Health. 
In addition, a waiver of fees associated with the administering and issuance of 
a food employee certificate (in compliance with A.R.S. § 41-1080) may be 
granted to a current student, enrolled in a K-12 culinary arts school program or 
similar curriculum-based programs requiring food employee certificates. The 
sponsoring school district must demonstrate to the Board of Health that 
payment of said fee will cause financial hardship. 
Again, all fee waiver applications reviewed this quarter appear to meet the 
criteria.  
President MacMillan asked the Board for a motion to approve the Fee Waiver 
Application Summary Sheet. 
•
Motion: Dr. Matthew Farber
•
Second: Dr. Paul Stander
•
Motion status: Approved unanimously
5. 
Air Quality Department  
Approve initiation of regulatory change for the three rules: 
Greg Verkamp explained that to initiate any changes to Air Quality rules, the Board 
of Health must approve the initiation process. It is one of the first steps in 
rulemaking. Stakeholder workshops were/will be held. 
•
Supervisor Gates asked that Air Quality reach out to Merissa Hamilton who has
expressed interest in the process. Kimberly Butler has provided Merissa with
her contact information.
Greg 
Verkamp/ 
Kimberly 
Butler 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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MARICOPA COUNTY BOARD OF HEALTH 
AUGUST 28, 2023 – MEETING MINUTES 
resident MacMillan asked the Board for a motion to approve AQ-2022-003 Rule 
313. 
A. AQ-2022-003 Rule 313 (Incinerators, Burn-Off Ovens, and Crematories)
The Maricopa County Air Quality Department (MCAQD) is proposing to revise
Rule 313 to clarify, update, and restructure the rule. Upon adoption of the
revised rule, MCAQD plans to submit the rule to the U.S. Environmental
Protection Agency (EPA) to replace Rule 35 (Incinerators) and the 2012 version
of Rule 313 in the Arizona State Implementation Plan (SIP).
•
Motion: Dr. Matthew Farber
•
Second: Paula Banahan
•
Motion status: Approved unanimously
President MacMillan asked the Board for a motion to approve AQ-2022-004 Rule 
330. 
B. AQ-2022-004 Rule 330 (Volatile Organic Compounds)
MCAQD is proposing to revise Rule 330 to clarify, update, and restructure the
rule. Proposed revisions include clarifying the purpose of the rule, removing
outdated provisions more thoroughly addressed in other MCAQD rules, and
restructuring the rule to ensure consistency within the Maricopa County Air
Pollution Control Regulations.
•
Motion: Dr. Debra Baldauff
•
Second: Dr. Matthew Farber
•
Motion status: Approved unanimously
President MacMillan asked the Board for a motion to approve AQ-2023-003 Rule 
331. 
C. AQ-2023-003 Rule 331 (Solvent Cleaning)
MCAQD is proposing to revise Rule 331 to remove a Reasonably Available
Control Technology (RACT) deficiency identified by the EPA so the rule can be
approved into the Arizona SIP as meeting RACT. MCAQD is also considering
other revisions to improve and clarify the rule. In addition, MCAQD plans to
replace SIP Rule 34, Sections F-K (Organic Solvents – Volatile Organic
Compounds (VOC)) with the revised rule to update the SIP and clarify
regulatory requirements.
•
Motion: Dr. Matthew Farber
•
Second: Lorenzo Sierra
•
Motion status: Approved unanimously
6. 
Adjournment 
President MacMillan asked the Board for a motion to adjourn. 
•
Motion: Paula Banahan
•
Second: Dr. Matthew Farber
•
Motion status: Approved unanimously
The meeting ended at 4:38 pm 
President 
MacMillan 
3 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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Minutes from Board of Health meeting - July 22, 2024
(Pending)
Return to list of attachments
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
76 of 94

Subject:
FW: Comments for Rule 330 (Volatile Organic Compounds) and Rule 331 (Solvent Cleaning) 
Revisions
From: Hana De Leon <hana.deleon@nxp.com>  
Sent: Tuesday, June 20, 2023 7:53 AM 
To: AQD Planning SM <AQPlanning@maricopa.gov> 
Cc: Peggy Felice <peggy.felice@nxp.com> 
Subject: Comments for Rule 330 (Volatile Organic Compounds) and Rule 331 (Solvent Cleaning) Revisions 
Below please find NXP’s input regarding proposed revisions to Rule 330 (Volatile Organic Compounds (VOCs)) 
and Rule 331 (Solvent Cleaning). 
We suggest the following modifications to the draft rules 330 and 331 to ensure consistency between these two rules as 
well as Rule 338 (Semiconductor Manufacturing): 

Modify section 502.3 of rule 331 to match section 502.3 in rule 330 and 338:
o
For each day or period the O&M Plan requires maintenance, the owner or operator shall make a
permanent record of the maintenance actions taken within 24 hours
3 business days of the maintenance completion.

Modify section 503.2 of Rule 330 to be consistent with section 503.2 of Revised Rule 338:
o
The ECS control efficiency shall be determined by measuring the VOC content of gaseous emissions
entering and exiting the ECS using the method in Section 504.1(b) of this rule (EPA Method 18) or the
method in Section 504.1(e) of this rule (EPA Method 25).

Modify section 503.3 of Rule 330 to match section 503.3 of Revised Rule 338:
o
The ECS capture efficiency shall be determined using one of the methods in Section 504.1(e) of this rule
(EPA Method 204, 204A, 204B, 204C, 204D, 204E, or 204F) or by using mass balance in combination with
ventilation/draft rate determinations made using one of the methods in Section 504.1(a) of this rule
(EPA Methods 2, 2A, 2C, or 2D). Verification that all active hoods and ducts, when measured at any
selection of any interior place within them, are at negative pressure relative to adjacent, uncaptured air
shall suffice for routine and uncontested demonstration of capture adequacy.
Hana De Leon 
Environmental Engineer 
NXP Semiconductors 
Return to list of attachments
Copies of all written and electronic Stakeholder input
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
77 of 94

Subject:
FW: Online Form Submittal: Citizen Comments
From: Michele Ross (COA) <Michele.Ross@maricopa.gov>  
Sent: Monday, 24 July, 2023 11:23 AM 
To: Will Adrian (AQD) <William.Adrian@maricopa.gov>; Michelle Mada (AQD) <Michelle.Mada@Maricopa.gov>; 
Kimberly Butler (AQD) <Kimberly.Butler@Maricopa.gov> 
Subject: FW: Online Form Submittal: Citizen Comments 
Please see citizen comment below. 
Thank you, 
Michele Ross 
Program Manager 
County Manager’s Office 
O: 602-506-0583 
[ Maricopa.Gov ] 
Facebook | Instagram | Twitter | YouTube | LinkedIn 
From: noreply@civicplus.com <noreply@civicplus.com>  
Sent: Monday, July 24, 2023 11:18 AM 
To: PND Regulatory <PNDRegulatory@maricopa.gov>; Kathy Semder (HSD) <Kathy.Semder@Maricopa.Gov>; Andy 
Linton (ENV) <Andy.Linton@Maricopa.Gov>; Bill Leal (DOT) <Bill.Leal@Maricopa.Gov>; Kathryn Garcia (PND) 
<Kathryn.Garcia@Maricopa.Gov>; Blanca Caballero (ENV) <Blanca.Caballero@Maricopa.gov>; Michele Ross (COA) 
<Michele.Ross@maricopa.gov> 
Subject: Online Form Submittal: Citizen Comments 
Citizen Comments 
Each Regulatory Department is committed to providing opportunities for 
stakeholder input regarding the adoption and amendment of all regulatory 
requirements. Your input will be collected and forwarded to the appropriate 
department. You will receive a written response from the applicable department 
within two business days. We appreciate your comments and your time. 
Case Number/Rule 
AQ-2023-003-Rule 331 (Solvent Cleaning) 
Department 
Air Quality 
I would like to  
Express opposition 
First Name 
Gary 
Last Name 
Jones 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
78 of 94

Organization 
Printing United Alliance 
City 
Pittsburgh 
Zip 
15237 
Email 
gjones@printing.org 
Phone Number 
4126574565 
Phone Type 
Mobile 
Would you like someone to 
contact you? 
Yes 
Comments 
I apologize in that I missed the initial outreach meeting on this 
rulemaking action. My comment pertains to the change in the 
definition of low VOC from 50 grams/liter to 25 grams/liter. This 
is quite a dramatic change to an already low VOC content, and 
I was not able to find any technical or economic analysis of this 
change. Unless this change can be shown to be both 
economically and technically feasible, it should not be made.  
Please provide the justification for this change showing that it is 
reasonable and there are products on the market that can 
accomplish the cleaning objectives at an affordable cost. 
If applicable, attach 
supporting documentation 
associated with your 
comment. The only file 
types supported are MS 
Office and Adobe Acrobat. 
Field not completed. 
Email not displaying correctly? View it in your browser.  
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
79 of 94

Subject:
FW: AQ-2023-003-Rule 331 Citizen Comment
From: Gary Jones <gjones@printing.org>  
Sent: Thursday, August 3, 2023 11:20 AM 
To: Hannah Luke (AQD) <Hannah.Luke@Maricopa.gov>; Gregory Verkamp (AQD) <Gregory.Verkamp@Maricopa.gov> 
Cc: Sara Osorio <sosorio@printing.org> 
Subject: RE: AQ-2023-003-Rule 331 Citizen Comment 
Hi Hannah, 
Great! Please let us know when you get feedback from EPA on the draŌ rule revisions. 
Gary Jones  
Vice President, Environmental, Health, and Safety Affairs 
PRINTING United Alliance 
10015 Main St., Fairfax, VA 22031 
703-359-1363 | gjones@prinƟng.org
From: Hannah Luke (AQD) <Hannah.Luke@Maricopa.gov>  
Sent: Thursday, August 3, 2023 2:13 PM 
To: Gary Jones <gjones@printing.org>; Gregory Verkamp (AQD) <Gregory.Verkamp@Maricopa.gov> 
Cc: Sara Osorio <sosorio@printing.org> 
Subject: RE: AQ-2023-003-Rule 331 Citizen Comment 
Hi Gary, 
Thank you for the addiƟonal informaƟon. As of right now, we are sƟll planning on keeping the alternaƟve vapor pressure 
limit in the rule. We hope to send the draŌ rule to the EPA soon for feedback. Should anything change that would need 
further discussion regarding graphic arts solvent cleaning, I will be sure to reach out to you. We will be having an 
addiƟonal workshop eventually which will cover any changes made to the draŌ rule since the first workshop.  
Please feel free to reach out to me with any quesƟons you might have. 
Thank you,  
Hannah Luke 
Senior Planner 
Air Quality 
301 W. Jefferson St., Suite 410 Phoenix, AZ 85003
O: 602-506-6706 C: 602-526-4148
E: Hannah.Luke@Maricopa.Gov 
[ Maricopa.Gov ] 
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Customer Satisfaction Survey
From: Gary Jones <gjones@printing.org>  
Sent: Thursday, August 3, 2023 10:41 AM 
To: Hannah Luke (AQD) <Hannah.Luke@Maricopa.gov>; Gregory Verkamp (AQD) <Gregory.Verkamp@Maricopa.gov> 
Cc: Sara Osorio <sosorio@printing.org> 
Subject: RE: AQ-2023-003-Rule 331 Citizen Comment 
Hi Hannah and Gregory, 
When we had our call last week, one of the acƟon items I had was to follow up on the cleaning soluƟons used in the 
stand-alone cleaning equipment for prinƟng applicaƟons regarding the VOC content and vapor pressure limits. I went 
back and reviewed the email exchanges we had with NY State DEC when they revised their cold cleaning rule several 
years ago and they were clear that they could not meet the 25 gram/liter limit but could meet the 1.0 mm Hg vapor 
pressure limit. 
They were not able to idenƟfy any materials or combinaƟon of materials that could be used to meet the 25 gram/liter 
limit. In looking at the email exchanges, it was briefly menƟoned that this low VOC content level would force vendors 
such as them to consider alternaƟves such as using causƟcs, exempt compounds, or other low VOC chemicals. It was 
concluded that these approaches would not necessarily be compaƟble with the prinƟng components being cleaned or 
would pose serious safety concerns. Therefore, they were not explored.  
The inability to meet the 25 gram/liter limit is why we requested and received an interpretaƟon that these units would 
not fall under the cold cleaner regulaƟons and would fall under the prinƟng regulaƟons. 
Regarding the proposal to revise the cold cleaning requirements for Maricopa County, maintaining the 1 mm Hg vapor 
pressure opƟon is going to be criƟcal to allow these units to be purchased and used by prinƟng operaƟons. The 25 
gram/liter limit will not be a viable opƟon.  
If the 1 mm Hg limit will be eliminated as an opƟon, we would request that an exclusion for this type of equipment be 
added to the regulaƟon. We can work with you on the language to be added if this were to occur. 
Please let us know if you have any quesƟons or need addiƟonal informaƟon.  
Gary Jones  
Vice President, Environmental, Health, and Safety Affairs 
PRINTING United Alliance 
10015 Main St., Fairfax, VA 22031 
703-359-1363 | gjones@prinƟng.org
From: Hannah Luke (AQD) <Hannah.Luke@Maricopa.gov>  
Sent: Monday, July 24, 2023 5:04 PM 
To: Gary Jones <gjones@printing.org> 
Cc: Gregory Verkamp (AQD) <Gregory.Verkamp@Maricopa.gov> 
Subject: AQ-2023-003-Rule 331 Citizen Comment 
Good aŌernoon Mr. Jones,  
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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We received your ciƟzen comment regarding draŌ Rule 331 and would like to set up a virtual meeƟng to discuss further. 
Can you please provide a couple of dates that you are available so we can get something scheduled? 
Thank you, 
Hannah Luke 
Senior Planner 
Air Quality 
301 W. Jefferson St., Suite 410 Phoenix, AZ 85003
O: 602-506-6706 C: 602-526-4148
E: Hannah.Luke@Maricopa.Gov 
[ Maricopa.Gov ] 
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Customer Satisfaction Survey
Join us at PRINTING United EXPO! 
(Oct. 18-20, Atlanta)  
Connect with PRINTING United Alliance on Social Media: 
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Contact PRINTING United Alliance for membership inquiries. 
Join us at PRINTING United EXPO! 
(Oct. 18-20, Atlanta)  
Connect with PRINTING United Alliance on Social Media: 
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Contact PRINTING United Alliance for membership inquiries. 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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Subject:
FW: Intel Comments to MCAQD proposed Rule 330, 331, 338 20240223.pdf
From: Hannah Luke (AQD)  
Sent: Monday, February 26, 2024 8:04 AM 
To: D'Oria, Gary R <gary.r.doria@intel.com> 
Cc: Kabiri-badr, Leila <leila.kabiri-badr@intel.com>; Zambrano, Oscar <oscar.zambrano@intel.com>; Gregory Verkamp 
(AQD) <Gregory.Verkamp@Maricopa.gov> 
Subject: RE: Intel Comments to MCAQD proposed Rule 330, 331, 338 20240223.pdf 
Hi Gary, 
Thank you for providing Intel’s comments on Rules 330, 331, and 338. We will begin reviewing internally and get back to 
you shortly with suggested dates/times to meet and discuss further. Please let me know if you have any questions.  
Hannah Luke 
Senior Planner 
Air Quality 
301 W. Jefferson St., Suite 410 Phoenix, AZ 85003
O: 602-506-6706 C: 602-526-4148
E: Hannah.Luke@Maricopa.Gov 
[ Maricopa.Gov ] 
Facebook | Instagram | Twitter | YouTube | LinkedIn 
 
Customer Satisfaction Survey
From: D'Oria, Gary R <gary.r.doria@intel.com>  
Sent: Monday, February 26, 2024 7:49 AM 
To: Hannah Luke (AQD) <Hannah.Luke@Maricopa.gov> 
Cc: Kabiri-badr, Leila <leila.kabiri-badr@intel.com>; Zambrano, Oscar <oscar.zambrano@intel.com> 
Subject: Intel Comments to MCAQD proposed Rule 330, 331, 338 20240223.pdf 
Hannah. Regretfully, I just now realized this didn’t get emailed Friday. . . Please let us know when you’d like to discuss our comments later this week, and perhaps suggest several times that may work on our calendars. Regards, Gary  
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Hannah. 
Regretfully, I just now realized this didn’t get emailed Friday...  
Please let us know when you’d like to discuss our comments later this week, and perhaps suggest several times that may 
work on our calendars. 
Regards,  
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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Gary D’Oria 
TD Environmental Engineer 
Intel Corporation | Chandler Campus 
(480) 241-4917
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EMAIL DELIVERY 
February 23, 2024 
Hannah Luke 
Air Quality  
Maricopa County Air Quality Department 
301 W. Jefferson St., Suite 410  
Phoenix, AZ 85003  
Email: Hannah.Luke@Maricopa.Gov    
RE: 
Intel Corporation Comments on MCAQD Proposed Rule 330, 331 & 338 
Dear Ms. Luke: 
Intel Corporation (Intel) submits the following comments on the Maricopa County Air 
Quality Department (MCAQD) proposed changes to Rule 338.  Intel operates semiconductor 
manufacturing in Arizona with 6 world-class fabrication (Fab) sites in operation and under 
construction at our Ocotillo Campus and world class research and development at our Chandler 
Campus. 
Intel, with many others has participated in the stakeholder process for MCAQD’s proposed 
rules and appreciates MCAQD’s willingness to discuss key issues of importance during the 
stakeholder process.  The Intel Chandler research and development (aka TD) facility has uses 
isopropyl alcohol (IPA) in open bath parts cleaning and in wipe cleaning. These uses and respective 
emissions are included in the air emissions inventory (AEI) and result in high volume low 
concentration mass emissions.  However, Intel believes the rulemaking may have significant, 
adverse consequences on the Intel Chandler Campus and feels it is necessary to submit additional 
company comments on these proposed rules. Some areas using IPA in this manner have very low 
emissions and are not currently equipped with an emission control system (ECS). Even in buildings 
that currently have an ECS, (e.g. CH4 building RTO) connecting these IPA using sources would 
result in significant increases in the total flow into the system from sources with low VOC 
concentration. Connecting these dilute sources will result in a higher flow, lower concentration 
stream which will increase the NOx emissions from the existing ECS and likely lower its overall 
removal efficiency. In addition, connecting these new VOC sources would result in significant 
increases in the total flow requiring additional capacity and a new ECS. Specific concerns follow. 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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Proposed Rule 330 
Based on our current Air Permit, the Intel Chandler campus is projected to have total pre-control 
emissions > 25 TPY VOCs.  The proposed rule 330 would require that the entire amount of this 
discharge must be connected to an ECS that meets 85% capture and control (excluding materials 
with < 20% VOC content or < 1 mmHg vapor pressure). The Intel Chandler TD operations may 
include wipe cleaning.  These operations are exempted from control requirements in the proposed 
rule 331 but would appear to require control in the rule 330 proposal. While 330 does state that it 
applies to sources not regulated by more source specific rules, Intel would like to clarify that the 
blanket provisions of rule 330 do not create a control requirement for wipe cleaning, as the 331 
provisions exempt wipe cleaning from control requirements.  Attempting to route wipe cleaning 
emissions to an ECS is not practical as this is performed across the factory in many locations. If 
these sources were connected to a ECS the result would be a very high flow, dilute exhaust stream 
driving significant increases in NOx that would likely exceed current Air Permit Limits.   
Proposed Rule 331 
In general, this rule could be made clearer and explicitly state the requirements for cleaning 
machines that can be done to avoid an ECS. In CH solvent “cleaning machines” are impacted as 
they don’t have a "remote reservoir" or non-remote internal reservoir".  Cleaning machines use 
IPA solvent with a volume > than 1 square foot and > 1 gallon with VP > than 1mm Hg. 
Attempting to route “cleaning machine” emissions to an ECS is not practical as these sources if 
connected to a ECS the result would be a very high flow, dilute exhaust stream driving significant 
increases in NOx that would likely exceed current Air Permit Limits. 
Proposed Rule 338 
Section 401.3 requires any modifications to ECS to be completed and unit source tested within 12 
months of applicability.  This timeline is too short for this requirement to add new emission control 
system (ECS) capacity, with Air Permitting, construction supporting ductwork within the 
cleanroom combined with external ductwork using steel and concrete.  Construction projects 
timelines are for projects of this scale are in the 3-year timeframes.  
TD Environmental Engineering, Environmental Health & Safety 
Intel Corporation | 5000 W Chandler Blvd  
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Subject:
FW: MCAQD Rule 338 Comment 
Attachments:
Intel Chandler Campus Comments to MCAQD proposed Rule 330 331 338 20240319.pdf
From: D'Oria, Gary R <gary.r.doria@intel.com>  
Sent: Tuesday, March 19, 2024 3:23 PM 
To: Hannah Luke (AQD) <Hannah.Luke@Maricopa.gov> 
Cc: Gregory Verkamp (AQD) <Gregory.Verkamp@Maricopa.gov>; Kabiri-badr, Leila <leila.kabiri-badr@intel.com>; 
Zambrano, Oscar <oscar.zambrano@intel.com> 
Subject: RE: MCAQD Rule 338 Comment  
Hannah. See attached second round of comments on the AQD Proposed Rules changes. Looking forward to discussions this Thursday. Thanks Gary From: Hannah Luke (AQD) <Hannah. Luke@ Maricopa. gov> Sent: Thursday, March 7, 2024 3: 01 PM To: D'Oria,  
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Hannah. 
See aƩached second round of comments on the AQD Proposed Rules changes. Looking forward to discussions this 
Thursday. 
Thanks  
Gary 
From: Hannah Luke (AQD) <Hannah.Luke@Maricopa.gov>  
Sent: Thursday, March 7, 2024 3:01 PM 
To: D'Oria, Gary R <gary.r.doria@intel.com> 
Cc: Gregory Verkamp (AQD) <Gregory.Verkamp@Maricopa.gov> 
Subject: MCAQD Rule 338 Comment  
Hi Gary, 
We met with the EPA and were able to discuss Intel’s comment on Rule 338 SecƟon 401.3. The EPA would like addiƟonal 
jusƟficaƟon on the requested Ɵmeframe increase. If possible, please provide supporƟng informaƟon that would 
demonstrate the need for the Ɵmeframe related to modificaƟons to an ECS.  
Would you be able to provide this informaƟon by next Friday 3/15, in addiƟon to the solvent cleaning machine 
equipment details? 
Thank you, 
Hannah Luke 
Senior Planner 
Air Quality 
301 W. Jefferson St., Suite 410 Phoenix, AZ 85003
O: 602-506-6706 C: 602-526-4148
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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E: Hannah.Luke@Maricopa.Gov 
[ Maricopa.Gov ] 
Facebook | Instagram | Twitter | YouTube | LinkedIn 
 
Customer Satisfaction Survey
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EMAIL DELIVERY 
March 19, 2024 
Hannah Luke 
Air Quality  
Maricopa County Air Quality Department 
301 W. Jefferson St., Suite 410  
Phoenix, AZ 85003  
Email: Hannah.Luke@Maricopa.Gov    
RE: 
Intel Corporation Comments on MCAQD Proposed Rule 330, 331 & 338 
Dear Ms. Luke: 
Intel Corporation (Intel) is providing a follow-up to our February 23, 2024, comments on the 
Maricopa County Air Quality Department (MCAQD) proposed changes to Rule 331 and Rule 
338. These comments are addressing concerns and considerations for the Assembly Test
Technology Development (ATTD) or Research and Development (R&D) at our Chandler
Campus. In this meeting we agreed to provide additional evaluations of the solvent cleaning
activities that are possibly impacted by the modifications in Rule 331§ 302.2 & 302.3.
As stated in the last comment letter, the current Air Permit limits the Intel Chandler campus to no 
more than 35 TPY VOCs. This is greater than the Proposed Rule 330 total pre-control emissions 
of no more than 25 TPY VOCs. The proposed Rule 330 would require that the entire amount of 
this discharge must be connected to an ECS that meets 85% capture and control (excluding 
materials with < 20% VOC content or < 1 mmHg vapor pressure). Rule 330 states that it applies 
to sources not regulated by more specific rules.  
In this solvent cleaning evaluation, we discovered that semiconductor substrate R&D non-
solvent cleaning wet plating (aqueous) tools would now be required to be connected to an ECS 
by Rule 338 vs. Rule 331 due to Rule 338 broadened applicability and the Vapor Pressure 
requirement in the Rule 331 defining a conforming solvent as ≤1 mmHg. Connecting these non-
solvent cleaning wet plating tool sources to a ECS would result in high flow, low VOC 
concentrations in the exhaust leading to what we feel are counterproductive increases in NOx. 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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Specifically, Intel’s current estimates from these tools is ~1,300 lbs./year VOCs requiring an 
additional ~10,000 cfm of exhaust connected to an ECS, which could potentially result in an 
additional ~8600 lbs. of NOx per year.  We would like your comments of our analysis showing 
the expansion of the Rule 338 applicability beyond photoresist operations that may now regulate 
many wet plating tools.  These wet plating tools have water content slightly under 95% with 
relatively low VOC emissions but high NOx releases when connected to an ECS.  
Intel utilizes a number of “batch” cleaning machines, some of which use non-conforming 
solvents and are not small enough to be considered small cleaners.  However, it is our 
understanding that rule 331 would not require such machines to be connected to an ECS as 
section 302.c(4) states that a non-conforming solvent may be used if one of conditions “a” 
through “c” are met.  Part “c” of this section exempts certain SIC codes described in section 
103.3 including electronics manufacturing, which is the category Intel fits in.  Based on this it is 
our conclusion that batch cleaning systems would not be required to be connected to an ECS. We 
would appreciate your thoughts on if we’re interpreting this correctly. The Proposed Rule 331 
could appear to require that some in-line cleaning systems be connected to an ECS as section 
302.3 does not include the section 103.3 SIC Code exemption for in-line cleaning machines.  Our 
review of the semiconductor solvent cleaning equipment that use IPA and EtOH and covered by 
this Rule has identified requirements to connect to an ECS. Our estimates show that this could 
result in an additional 5000 cfm of exhaust connected to an ECS, which could potentially result 
in an additional ~2200 lbs. of NOx per year.  Intel’s current estimates of VOCs from these tools 
is < ~10,000 lbs./year, so this rule would result in generating 2200 lbs. NOx to remove this 
quantity of VOCs. 
In a follow-up email from our meeting, it was requested that we provide additional detail on our 
concerns with proposed Rule 338 401.3 timeframes. Our suggested language for 401.3 b. with 
rational follows. 
Within 12 months after the facility becomes subject to the requirements in section 301.1 
of this rule, the owner or operator shall be complete with ECS modifications for any 
existing ECS with existing infrastructure and existing capacity and perform “start-up” 
in accordance with Rule 270. Submittal to the Control Officer of a complete source test 
report indicating compliance shall be provided in the timeframes defined by Rule 270.   
Within 36 months after the facility becomes subject to the requirements in section 301.1 
of this rule, the owner or operator shall be complete with ECS modifications for any new 
ECS requiring new infrastructure and new capacity and perform “start-up” in 
accordance with Rule 270. Submittal to the Control Officer of a complete source test 
report indicating compliance shall be provided in the timeframes defined by Rule 270. 
Any “reconstructing or adding on equipment” is in our experience considered new infrastructure 
and new capacity and would requires 36 months for construction completion. Intel Chandler has 
recently installed VOC Abatement units that can be used as an example of construction 
schedules for reconstruction or addition of equipment. There was a need to expand the VOC 
abatement capacity due to new tools supporting technology development. Intel semiconductor 
construction schedules are some of the most aggressive in the industry due to the time-to-market 
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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strategy driving product technology advancements. In this example assume that a “plan of 
record” (POR) ECS is selected. This POR means that ECS supplier selection with contracts in 
place with performance specifications, master design standards, operating specifications and any 
treatability studies needed. Otherwise, this can take an additional 6-9 months to develop an Intel 
POR ECS. A brief example of construction schedules follows. 
•
3-6 Months for Design Positioning / Programing, this may include ductwork design and
layout within the cleanroom.
•
18-30 Months for Design Construction – this may include ductwork design and layout
within the cleanroom and staging of construction to avoid impacts to manufacturing
operations.
We appreciate the opportunity to provide comments to these proposed rules and welcome future 
meetings for guidance and to discuss our concerns and considerations.  
TD Environmental Engineering, Environmental Health & Safety 
Intel Corporation | 5000 W Chandler Blvd  
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Subject:
FW: Intel Follow-up from MCAQD Meeting 3/26/2024
From: D'Oria, Gary R <gary.r.doria@intel.com>  
Sent: Monday, April 1, 2024 7:16 AM 
To: Hannah Luke (AQD) <Hannah.Luke@Maricopa.gov>; Gregory Verkamp (AQD) <Gregory.Verkamp@Maricopa.gov> 
Cc: Kabiri-badr, Leila <leila.kabiri-badr@intel.com>; TIM HIGGS <tghiggs@cox.net> 
Subject: Intel Follow-up from MCAQD Meeting 3/26/2024 
Hi Hannah, From our discussions last week, we were to follow-up with you and Greg regarding the exemption for Substrates R&D Non-Solvent Wet Processing Plating tools (i. e. , Substrate Packaging Technology Development, SPTD) Suggested clarifications  
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Hi Hannah, 
From our discussions last week, we were to follow-up with you and Greg regarding the exemption for 
Substrates R&D Non-Solvent Wet Processing Plating tools (i.e., Substrate Packaging Technology Development, 
SPTD)  
Suggested clarifications to the Proposed New Rule 338 existing language for exemption for R&D  
Semiconductor Substrate R&D non-solvent cleaning wet plating (aqueous) tools, previously shown in our letter 
dated 3/19 would now be required to be connected to an ECS by Rule 338 vs. 331. In our meeting we read 
Rule 338 103.1 to exempt these tools because they are R&D. “research” and < 5 TPY can you please confirm. If 
you confirm this , then we recommend minor edits to Rule 338 to make this clearer by; 

Defining R&D in Rule 338 SECTION 200 similar to the R&D definition found in 40 CFR § 63.11511(d)(2)
(NESHAPS, 6W); “Research and development process unit means any process unit that is used for
conducting research and development for new processes and products and is not used to
manufacture products for commercial sale, except in a de minimis manner.” Note Intel SPTD is subject
to this NEESHAP exemption as noted in our Air Permit and TDS.

In addition, within Rule 338, 103.1 replace the ref. “research” to “research and development” to be
consistent throughout Rule 338.
Maricopa County • Air Quality Department • Report the the Board of Supervisors 
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Suggested clarifications to the Proposed New Rule 331, language for Partial Exemptions in 103.3  

The SICs Codes for Industry Group 367 ( Semiconductor Operations) are not referenced in 103.3.  Both
Intel Chandler Campus and Ocotillo Campus are both SIC Code 3674, and we can assume that NXP and
TSMC are also 3674. Can you add SIC Code 3674 to 103.3 to include these Semiconductor Operations
thatare most significant in Maricopa County and as discussed meeting the intent of the exemption?

Also, in support of adding SIC Code 3674, the SIC Codes listed do not correspond with the 103.4 ISO
cleanroom requirements. In other words, the SIC Codes referenced in 103.3 do need the cleanrooms
referenced in 103.4.

Considering this current language above, in the 3/19 second letter where we incorrectly stated that
our R&D Batch cleaning was exempt due to 331 103.3 (i.e., SIC Code 3674 was missing), whereas we
should have referenced 103.4 (i.e., ISO).

Note, in 302.2c.(4) Non-Conforming Solvent references 103.3 (SIC) which does not include Intel
Semiconductors in the exemption and instead could replace 103.3 with 103.4 or add both 103.3 and
103.4?

Inconclusion adding 3674 SIC Code to 103.3 may clarify the Partial Exemptions in Proposed New Rule
331, 103.
As a reminder I’m on sick leave from 4/1 and returning to work 4/15 with Leila Kabiri covering for me during this time. 
Regards, 
Gary 
480.241.4917 
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Maricopa County 
Air Quality Department 
Planning and Analysis Division 
Maricopa.gov/AQ