CALGreen · California Green Building Standards Code (CALGreen)

Indoor air quality: construction filters, direct‑vent appliances and low‑emitting materials

Q: How do I prove resilient flooring or insulation compliance?

A: The code requires documentation that the materials are certified to meet CDPH 01350 or the stated pollutant emission limits. Collect manufacturer or third‑party certification tied to CDPH 01350. § A4.504.2 / § A4.504.3.

During construction, CALGreen requires MERV 8 filters on HVAC return openings when equipment is used, direct‑vent appliances (or an isolated mechanical room) for equipment in conditioned space, and resilient flooring plus insulation that meet CDPH 01350 low‑emitting criteria (with documentation); see §§ A4.506.2, A4.506.3, A4.504.2 and A4.504.3 for the controlling rules.

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

In plain English: during construction, supply HVAC return‑air openings with filters rated MERV 8 or higher; appliances located inside conditioned space must be direct‑vent or the equipment must be installed in an isolated mechanical room; and certain interior finishes (resilient flooring and thermal insulation) must meet California’s low‑emitting material requirements and documentation rules. The controlling sections are § A4.506.2 and § A4.506.3 for construction and appliances, and § A4.504.2 and § A4.504.3 for resilient flooring and insulation respectively.

During construction use at least MERV 8 filters on return openings, use direct‑vent appliances (or place combustion equipment in an isolated mechanical room), and install resilient flooring and insulation that meet California’s low‑emitting (CDPH 01350) criteria — with documentation.

Requirements in detail

1) Construction filters

Requirement: Provide filters on return air openings rated MERV 8 or higher when HVAC equipment is used during construction. This is a health‑risk (HR) measure intended to control dust and construction particulate entering the system. Controlling §: § A4.506.2.

2) Direct‑vent appliances and location of combustion equipment

Requirement: If space‑heating or cooling equipment (or water‑heating equipment) will be located in conditioned spaces, use direct‑vent heating and cooling equipment; alternatively install such equipment in an isolated mechanical room. Controlling §: § A4.506.3.
Practical effect: prevents appliance combustion products or outdoor air intake from contaminating the living space and reduces cross‑contamination of HVAC air.

3) Low‑emitting materials — resilient flooring and thermal insulation

Resilient flooring systems must meet CDPH 01350 (California Specification 01350) requirements; coverage thresholds differ by Tier:
- Tier 1: at least 90% of resilient flooring area must comply. Controlling §: § A4.504.2.
- Tier 2: 100% of resilient flooring area must comply (with an exception allowing up to 5% specialty purpose flooring). Controlling §: § A4.504.2.
Thermal insulation:
- Tier 1: insulation must comply with CDPH 01350 VOC emission testing. Controlling §: § A4.504.3.
- Tier 2: same as Tier 1 plus insulation shall not contain any added formaldehyde (i.e., no‑added‑formaldehyde). Controlling §: § A4.504.3.
Documentation: the code requires documentation verifying materials are certified to meet the pollutant emission limits called out in these sections. Controlling §s: § A4.504.2 and § A4.504.3.

Quick decision table

Topic	Requirement	Key value / threshold	When it applies	Code Reference
Construction filters	Filters on return air openings	MERV 8 or higher	When HVAC equipment is used during construction	§ A4.506.2
Direct‑vent appliances	Use direct‑vent equipment or install equipment in isolated mechanical room	Direct‑vent OR isolated mechanical room	When heating/cooling or water‑heating equipment is located in conditioned space	§ A4.506.3
Resilient flooring (Tier 1)	90% of area must meet CDPH 01350 emissions	≥ 90%	Tier 1 voluntary target (or local adoption)	§ A4.504.2
Resilient flooring (Tier 2)	100% of area must meet CDPH 01350; up to 5% specialty exception	100% (≤ 5% exception)	Tier 2 voluntary target (or local adoption)	§ A4.504.2
Thermal insulation (Tier 1)	Must meet CDPH 01350 emission limits	CDPH 01350 compliance	Tier 1	§ A4.504.3
Thermal insulation (Tier 2)	CDPH 01350 compliance and no added formaldehyde	No added formaldehyde	Tier 2	§ A4.504.3
Documentation	Provide certification that materials meet pollutant emission limits	—	When using low‑emitting material credits/tiers	§ A4.504.2 / § A4.504.3

Exceptions & special cases

The code text provided does not list additional exceptions for § A4.506.2 beyond “when it is necessary to use HVAC equipment” during construction — if HVAC is not used, the MERV‑8 filter requirement does not apply as written. § A4.506.2.
Tier 2 resilient flooring allows an exception up to 5% for specialty purpose flooring only; the code requires documentation to substantiate compliance. § A4.504.2.
For thermal insulation, Tier 2 adds the explicit prohibition on added formaldehyde; the code references CDPH 01350 testing for VOCs but does not list numeric VOC limits in these snippets — you must consult the CDPH 01350 spec or manufacturer certification for exact emission limits. § A4.504.3.

If you need the specific pollutant concentration limits used by CDPH 01350 (for product acceptance/certification), those numeric limits are not included in the retrieved CALGreen excerpts and must be obtained from the CDPH 01350 publication or certified product documentation.

Common mistakes

Assuming any filter is acceptable during construction — code requires MERV 8 or higher on return openings when HVAC equipment is used. § A4.506.2.
Installing combustion appliances inside conditioned space without confirming they are listed direct‑vent units or without providing an isolated mechanical room. § A4.506.3.
Treating CDPH 01350 compliance as optional — for Tier credit and many local adoptions documentation that materials meet the CDPH standard is required. § A4.504.2 / § A4.504.3.
Relying on generic product claims (e.g., “low VOC”) without manufacturer paperwork or third‑party certification tied to CDPH 01350 or the formaldehyde limits referenced by the code. § A4.504.2 / § A4.504.3.

Worked example — single‑family home under Tier 1 measures

Scenario: A 2,000 ft² single‑family house is being built and the builder is pursuing Tier 1 voluntary measures for environmental quality.

Steps applying the rules:

Construction filtration:
- During finishing, the builder runs the central HVAC occasionally for floor drying and dust control. The contractor must fit MERV 8 filters on each return opening for the duration that HVAC equipment is used. (Apply § A4.506.2.)
Combustion equipment location:
- The gas water heater and furnace are planned in a finished utility closet inside conditioned space. The builder either specifies listed direct‑vent models for both appliances or relocates the equipment into an isolated mechanical room to comply with § A4.506.3.
Resilient flooring:
- The home will install 1,200 ft² of resilient flooring. For Tier 1, at least 90% (1,080 ft²) of that resilient flooring must be certified to CDPH 01350; the builder collects manufacturer certificates and submits them as required by § A4.504.2.
Insulation:
- The builder selects insulation products certified to CDPH 01350 for VOCs to meet Tier 1 insulation requirements, and keeps the product certificates on file per § A4.504.3. (If Tier 2 were sought, the builder would also ensure no added formaldehyde.)

Numbers recap:

MERV rating required: ≥ MERV 8 (construction). § A4.506.2.
Resilient flooring Tier 1: ≥ 90% area CDPH 01350‑compliant. § A4.504.2.
Resilient flooring Tier 2: 100% (≤ 5% specialty exception). § A4.504.2.
Insulation Tier 2: no added formaldehyde plus CDPH 01350 compliance. § A4.504.3.

Related provisions

§ A4.504.1 — Use of composite wood products with no‑added‑formaldehyde (NAF) or ULEF resins (related to low‑formaldehyde material controls).
§ A4.506.1 — (Reserved in excerpts) other IAQ/exhaust provisions appear in nearby text; check local adoption.
A5.504.1 / A5.504.2 — Nonresidential IAQ measures (temporary ventilation and post‑construction flush out) that expand on construction IAQ practices for commercial buildings.
CDPH 01350 reference — CALGreen requires compliance with the California Department of Public Health “Standard Method” for emission testing; obtain product certification/testing details from CDPH or listed certification programs. (Referenced in § A4.504.2 and § A4.504.3.)

If you want, I can:

Create a short contractor checklist for on‑site use (filter sizes, where to place MERV 8 filters, and documentation pack list), or
Pull the exact CDPH 01350 numeric limits and typical manufacturer certificate language (note: CDPH text itself was not included in the uploaded files).

Code references

Grounded in the retrieved California Green Building Standards Code (CALGreen) — click a citation to read the verbatim passage:

CALGreen § 504.2 High relevance — show source text
Note: Documentation must be provided that verifies that finish materials are certified to meet the pollutant emission limits.

A4.504.2 Resilient flooring systems. Resilient flooring systems installed in the building shall meet the percentages specified in this section and meet the requirements of the California Department of Public Health, “Standard Method for the Testing and Evaluation of Volatile Organic Chemical Emissions from Indoor Sources Using Environmental Chambers,” Version 1.2, January 2017 (Emission testing method for California Specification 01350). See California Department of Public Health’s website for certification programs and testing labs.

https://www.cdph.ca.gov/Programs/CCDPHP/DEODC/EHLB/IAQ/Pages/VOC.aspx

Tier 1. At least 90 percent of the total area of resilient flooring installed shall comply.

Tier 2. 100 percent of the total area of resilient flooring installed shall comply.

Exception for Tier 2: An allowance for up to 5 percent specialty purpose flooring may be permitted.

Note: Documentation must be provided that verifies that finish materials are certified to meet the pollutant emission limits in this section.

A4.504.3 Thermal insulation. Thermal insulation installed in the building shall meet the following requirements:

Tier 1. Install thermal insulation that meet the requirements of the California Department of Public Health, “Standard Method for the Testing and Evaluation of Volatile Organic Chemical Emissions from Indoor Sources Using Environmental Chambers,” Version 1.2, January 2017 (Emission testing method for California Specification 01350).

See California Department of Public Health’s website for certification programs and testing labs.

https://www.cdph.ca.gov/Programs/CCDPHP/DEODC/EHLB/IAQ/Pages/VOC.aspx

Tier 2. Install insulation which complies with Tier 1 plus does not contain any added formaldehyde.

Note: Documentation must be provided that verifies the materials are certified to meet the pollutant emission limits in this section.

SECTION A4.505—INTERIOR MOISTURE CONTROL (RESERVED)

SECTION A4.506—INDOOR AIR QUALITY AND EXHAUST

A4.506.1 Reserved.

A4.506.2 Construction filter. [HR] Provide filters on return air openings rated at MERV 8 or higher during construction.

A4.506.3 Direct-vent appliances. Direct-vent heating and cooling equipment shall be utilized if the equipment will be located in the conditioned space or install the space heating and water heating equipment in an isolated mechanical room.

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-19

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

SECTION A4.507—ENVIRONMENTAL COMFORT (RESERVED)

SECTION A4.508—OUTDOOR AIR QUALITY (RESERVED)

SECTION A4.509 —INNOVATIVE CONCEPTS AND LOCAL ENVIRONMENTAL CONDITIONS
CALGreen § 506.1 High relevance — show source text
See California Department of Public Health’s website for certification programs and testing labs.

https://www.cdph.ca.gov/Programs/CCDPHP/DEODC/EHLB/IAQ/Pages/VOC.aspx

Tier 2. Install insulation which complies with Tier 1 plus does not contain any added formaldehyde.

Note: Documentation must be provided that verifies the materials are certified to meet the pollutant emission limits in this section.

SECTION A4.505—INTERIOR MOISTURE CONTROL (RESERVED)

SECTION A4.506—INDOOR AIR QUALITY AND EXHAUST

A4.506.1 Reserved.

A4.506.2 Construction filter. [HR] Provide filters on return air openings rated at MERV 8 or higher during construction.

A4.506.3 Direct-vent appliances. Direct-vent heating and cooling equipment shall be utilized if the equipment will be located in the conditioned space or install the space heating and water heating equipment in an isolated mechanical room.

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-19

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

SECTION A4.507—ENVIRONMENTAL COMFORT (RESERVED)

SECTION A4.508—OUTDOOR AIR QUALITY (RESERVED)

SECTION A4.509 —INNOVATIVE CONCEPTS AND LOCAL ENVIRONMENTAL CONDITIONS

A4.509.1 Innovative concepts and local environmental conditions. The provisions of this code are not intended to prevent the use of any alternate material, appliance, installation, device, arrangement, method, design or method of construction not specifically prescribed by this code. This code does not limit the authority of city, county, or city and county government to make necessary changes to the provisions contained in this code pursuant to Section 101.7.1.

APPENDIX A4-20 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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A4 RESIDENTIAL VOLUNTARY MEASURES

DIVISION A4.6 – TIER I AND TIER 2

SECTION A4.601—GENERAL

A4.601.1 Scope. The measures contained in this appendix are not mandatory unless adopted by a city, county, or city and county as specified in Section 101.7. The provisions of this section outline means of achieving enhanced construction or reach levels by incorporating additional green building measures. In order to meet one of the tier levels designers, builders or property owners are required to incorporate additional green building measures necessary to meet the threshold of each level.

A4.601.2 Prerequisite measures. Tier 1 and Tier 2 thresholds require compliance with the mandatory provisions of this code and incorporation of the required prerequisite measures listed in Section A4.601.4.2 for Tier 1 and A4.601.5.2 for Tier 2. Prerequisite measures are also identified in the Residential Occupancies Application Checklist in Section A4.602.

CALGreen § 504.1 High relevance — show source text

APPENDIX A4-28 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

SECTION A4.602—RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST—continued

FEATURE OR MEASURE	LEVELS APPLICANT TO SELECT ELECTIVE MEASURES	Col3	Col4	VERIFICATIONS ENFORCING AGENCY TO SPECIFY VERIFICATION METHOD	Col6	Col7
FEATURE OR MEASURE	Mandatory	Prerequisites and electives1	Prerequisites and electives1	Enforcing Agency  All	Installer or Designer  All	Third party  All
FEATURE OR MEASURE	Mandatory	Tier 1	Tier 2	Tier 2	Tier 2	Tier 2
A4.504.1Use composite wood products made with either California Air Resources Board approved no-added formaldehyde (NAF) resins or ultra-low emitting formaldehyde (ULEF) resins.						
A4.504.2Install VOC compliant resilient flooring systems. Tier 1. At least 90 percent of the resilient flooring installed shall comply. Tier 2.100 percent of the resilient flooring installed shall comply.		2	2			
A4.504.3Thermal insulation installed in the building shall meet the following requirements: Tier 1. Install thermal insulation in compliance with VOC limits. Tier 2. Install insulation which contains no-added formaldehyde (NAF) and is in compliance with Tier 1.		2	2			
Interior Moisture Control
4.505.2Vapor retarder and capillary break is installed at slab-on- grade foundations.						
4.505.3 Moisture content of building materials used in wall and floor framing is checked before enclosure.						
Indoor Air Quality and Exhaust
4.506.1 Each bathroom shall be provided with the following: 1. ENERGY STAR fans ducted to terminate outside the building. 2. Fans must be controlled by a humidity control (separate or built- in); OR functioning as a component of a whole-house ventilation system. 3.

CALGreen § 504.2 High relevance — show source text
504.2**Install VOC compliant resilient flooring systems.
Tier 1. At least 90 percent of the resilient flooring installed shall comply.
**Tier 2.**100 percent of the resilient flooring installed shall comply.||2|2|
|
|
| |A4.504.3Thermal insulation installed in the building shall meet the
following requirements:
Tier 1. Install thermal insulation in compliance with VOC limits.
Tier 2. Install insulation which contains no-added formaldehyde
(NAF) and is in compliance with Tier 1.||2|2|||| |Interior Moisture Control||||||| |4.505.2Vapor retarder and capillary break is installed at slab-on-
grade foundations.||||||| |4.505.3 Moisture content of building materials used in wall and floor
framing is checked before enclosure.||||||| |Indoor Air Quality and Exhaust||||||| |4.506.1 Each bathroom shall be provided with the following:
1. ENERGY STAR fans ducted to terminate outside the building.
2. Fans must be controlled by a humidity control (separate or built-
in); OR functioning as a component of a whole-house ventilation
system.
3. Humidity controls with manual or automatic means of
adjustment, capable of adjustment between a relative humidity
range of≤ 50 percent to a maximum of 80 percent.||||
|
|
| |A4.506.1 Reserved.||||||| |A4.506.2 [HR] Provide filters on return air openings rated MERV 8 or
higher during construction when it is necessary to use HVAC
equipment.||||||| |A4.506.3 Direct-vent appliances shall be used when equipment is
located in conditioned space; or the equipment must be installed in
an isolated mechanical room.||||||| |Environmental Comfort||||||| |4.507.2 Duct systems are sized, designed and equipment is selected
using the following methods:
1. Establish heat loss and heat gain values according to ANSI/ACCA 2
Manual J-2016 or equivalent.
2. Size duct systems according to ANSI/ACCA 1 Manual D-2016
or equivalent.
3. Select heating and cooling equipment according to ANSI/ACCA 3
Manual S-2014 or equivalent.
CALGreen § 3.1. High relevance — show source text
1. From Division A4.3, Water Efficiency and Conservation. 3.1. Comply with at least two elective measures selected from Division A4.3.
2. From Division A4.4, Material Conservation and Resource Efficiency. 4.1. Comply with the 20 percent cement reduction requirements in Section A4.403.2. 4.2. Comply with the 10 percent recycled content requirements in Section A4.405.3.1. 4.3. Comply with the 65 percent reduction in construction waste in Section A4.408.1. 4.4. Comply with at least two elective measures selected from Division A4.4.
3. From Division A4.5, Environmental Quality. 5.1. Comply with the 90 percent resilient flooring systems requirements in Section A4.504.2. 5.2. Comply with the thermal insulation requirements for Tier 1 in Section A4.504.3. 5.3. Comply with at least one elective measure selected from Division A4.5.
Note: The Residential Occupancies Application Checklist contained in Section A4.602 may be used to show which elective measures are selected.

A4.601.5 Tier 2. To achieve Tier 2 status a project must comply with the following.

Note: The measures necessary to achieve Tier 2 status are very stringent. Cities, counties, and cities and counties considering adoption of Tier 2 as mandatory should carefully consider the stringency of each measure and ensure that the measures are achievable in their location.

A4.601.5.1 Mandatory measures for Tier 2. The project shall meet or exceed all of the mandatory measures in Chapter 4, Divisions 4.1 through 4.5 and Chapter 7 as applicable.

A4.601.5.2 Prerequisite and elective measures for Tier 2. In addition to the mandatory measures, compliance with the following prerequisite and elective measures from Appendix A4 is also required to achieve Tier 2 status.
1. From Division A4.1, Planning and Design.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-21

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

1.1. Comply with the topsoil protection requirements for Tier 1 and Tier 2 in Section A4.106.2.3. 1.2. Comply with the 30 percent permeable paving requirements in Section A4.106.4. 1.3. Comply with the cool roof requirements in Section A4.106.5. 1.4. Comply with the Tier 2 electric vehicle (EV) charging requirements in Section A4.106.8. 1.5. Comply with at least four elective measures selected from Division A4.1. 2. From Division A4.2, Energy Efficiency. 2.1. For newly constructed low-rise residential buildings, comply with the energy efficiency requirements in Sections A4.203.1, A4.203.1.1, Table A4.203.1.1, A4.203.1.2 and A4.203.1.3.
1. From Division A4.3, Water Efficiency and Conservation. 3.1. Comply with at least three elective measures selected from Division A4.3.
2. From Division A4.4, Material Conservation and Resource Efficiency. 4.1.
CALGreen § 8-6 Medium relevance — show source text
. . . . . . . . . . . . . . . 8-6 Worksheet (WS-9) 5.409.2 and A5.409.2 Whole Building Life Cycle Assessment: . . . . . . . . . . . . . . . . 8-7 Construction Waste Management (CWM) Plan . . . . . . . . . . . 8-8 Construction Waste Management (CWM) Worksheet. . . . . . 8-9 Construction Waste Management (CWM) Acknowledgment. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10 Title 23, Waters, California Code of Regulations . . . . . . . . . 8-11 Commissioning Referenced Standards for Non-energy Systems. . . . . . . . . . . . . . . . . . . . . . . . . 8-13 IES TM-15-11 Table A-1, Table 130.2-A and Table 130.2-B Uplight and Glare Ratings Tables. . . . . . . . . . . . . . 8-40

APPENDIX A4 RESIDENTIAL

VOLUNTARY MEASURES. . . . . . . . . . . . . . . . . APPENDIX A4-3

A4.1 Planning and Design . . . . . . . . . . . . . . . . . APPENDIX A4-3 A4.2 Energy Efficiency . . . . . . . . . . . . . . . . . . . . APPENDIX A4-9 A4.3 Water Efficiency and Conservation . . . APPENDIX A4-13 A4.4 Material Conservation and Resource Efficiency . . . . . . . . . . . . . . . . . . . . . . . . APPENDIX A4-15 A4.5 Environmental Quality . . . . . . . . . . . . . . APPENDIX A4-19 A4.6 Tier 1 and Tier 2 . . . . . . . . . . . . . . . . . . . . APPENDIX A4-21

Division A4.6—Residential Occupancies Application Checklist . . . . . . . . . . . . . APPENDIX A4-23 A4.7 Residential Model Ordinance . . . . . . . . . APPENDIX A4-31

APPENDIX A5 NONRESIDENTIAL

VOLUNTARY MEASURES. . . . . . . . . . . . . . . . . APPENDIX A5-3
CALGreen § 6.4 Medium relevance — show source text
6.4_|||X|||||||||||||||||||||| |907.2.6.5|||X|||||||||||||||||||||| |907.2.9|||X|||||||||||||||||||||| |907.2.9.1|||X|||||||||||||||||||||| |907.2.9.3|||X|||||||||||||||||||||| |907.2.9.4|||X|||||||||||||||||||||| |907.2.9.4.1|||X|||||||||||||||||||||| |907.2.10|||X|||||||||||||||||||||| |907.2.11|||X|||||||||||||||||||||| |907.2.11.1|||X|||||||||||||||||||||| |907.2.11.2|||X|||||||||||||||||||||| |907.2.11.2.1 – 907.2.11.2.6|||X|||||||||||||||||||||| |907.2.11.3|||X|||||||||||||||||||||| |907.2.11.4|||X|||||||||||||||||||||| |907.2.11.6|||X|||||||||||||||||||||| |907.2.11.8|||X|||||||||||||||||||||| |907.2.11.9|||X|||||||||||||||||||||| |907.2.12|||X|||||||||||||||||||||| |907.2.13|||X|||||||||||||||||||||| |907.2.13.1|||X|||||||||||||||||||||| |907.2.13.1.2|||X|||||||||||||||||||||| |907.2.24 with subsections|||X|||||||||||||||||||||| |907.2.25 with subsections|||X|||||||||||||||||||||| |907.2.26 with subsections|||X|||||||||||||||||||||| |907.2.27|||X||||||||||||||||||||||

2025 CALIFORNIA BUILDING CODE 9-3

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CALIFORNIA BUILDING CODE – MATRIX ADOPTION TABLE

CHAPTER 9 – FIRE PROTECTION AND LIFE SAFETY SYSTEMS—continued
CALGreen § 601.5.2 Medium relevance — show source text
A4.601.5.2 Prerequisite and elective measures for Tier 2. In addition to the mandatory measures, compliance with the following prerequisite and elective measures from Appendix A4 is also required to achieve Tier 2 status.
1. From Division A4.1, Planning and Design.
2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A4-21

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APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

1.1. Comply with the topsoil protection requirements for Tier 1 and Tier 2 in Section A4.106.2.3. 1.2. Comply with the 30 percent permeable paving requirements in Section A4.106.4. 1.3. Comply with the cool roof requirements in Section A4.106.5. 1.4. Comply with the Tier 2 electric vehicle (EV) charging requirements in Section A4.106.8. 1.5. Comply with at least four elective measures selected from Division A4.1. 2. From Division A4.2, Energy Efficiency. 2.1. For newly constructed low-rise residential buildings, comply with the energy efficiency requirements in Sections A4.203.1, A4.203.1.1, Table A4.203.1.1, A4.203.1.2 and A4.203.1.3.
1. From Division A4.3, Water Efficiency and Conservation. 3.1. Comply with at least three elective measures selected from Division A4.3.
2. From Division A4.4, Material Conservation and Resource Efficiency. 4.1. Comply with the 25 percent cement reduction requirements in Section A4.403.2. 4.2. Comply with the 15 percent recycled content requirements in Section A4.405.3.1. 4.3. Comply with the 75 percent reduction in construction waste in Section A4.408.1. 4.4. Comply with at least four elective measures selected from Division A4.4.
3. From Division A4.5, Environmental Quality. 5.1. Comply with the 100 percent resilient flooring systems requirements in Section A4.504.2. 5.2. Comply with the thermal insulation requirements for Tier 1 and Tier 2 in Section A4.504.3. 5.3. Comply with at least one elective measure selected from Division A4.5.
Note: The Residential Occupancies Application Checklist contained in Section A4.602 may be used to show which elective measures are selected.

APPENDIX A4-22 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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DIVISION A4.6 – TIER 1 AND TIER 2

SECTION A4.602 — RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST
CALGreen § 501.1 Medium relevance — show source text
The state agency does not adopt sections identified by the following symbol: †.

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE APPENDIX A5-33

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APPENDIX A5-34 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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A5 NONRESIDENTIAL VOLUNTARY MEASURES

DIVISION A5.5 – ENVIRONMENTAL QUALITY

SECTION A5.501—GENERAL

A5.501.1 Scope. The provisions of this chapter shall outline means of reducing the quantity of air contaminants that are odorous, irritating and/or harmful to the comfort and well-being of a building’s installers, occupants and neighbors.

SECTION A5.502—DEFINITIONS

A5.502.1 Definitions. The following terms are defined in Chapter 2.

INTERIOR, BUILDING.

MERV. [BSC]

MULTI-OCCUPANT SPACES.

NO ADDED FORMALDEHYDE (NAF) BASED RESINS.

SINGLE OCCUPANT SPACES.

ULTRA-LOW EMITTING FORMALDEHYDE (ULEF) RESINS.

SECTION A5.504—POLLUTANT CONTROL

A5.504.1 Indoor air quality (IAQ) during construction. Maintain IAQ as provided in Sections A5.504.1.1 and A5.504.1.2.

A5.504.1.1 Temporary ventilation. Provide temporary ventilation during construction in accordance with Section 120.1 (Requirements for Ventilation) of the California Energy Code, CCR, Title 24, Part 6 and Chapter 4 of CCR, Title 8 and as follows:
1. Ventilation during construction shall be achieved through openings in the building shell using fans to produce a minimum of three air changes per hour.
2. If the building is occupied during demolition or construction, meet or exceed the recommended Control Measures of the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) IAQ Guidelines for Occupied Buildings under Construction, 1995, Chapter 3.
A5.504.1.2 Additional IAQ measures. Employ additional measures as follows:
1. When using generators to generate temporary power, use generators meeting the requirements of CCR, Title 13, Chapter 9 or local ordinance, whichever is more stringent.
2. Protect on-site absorbent materials from moisture. Remove and replace any materials with evidence of mold, mildew or moisture infiltration.
3. Store odorous and high VOC-emitting materials off-site, without packaging, for a sufficient period to allow odors and VOCs to disperse.
4. When possible, once materials are on the jobsite, install odorous and high VOC-emitting materials prior to those that are porous or fibrous.
5. Clean oil and dust from ducts prior to use.
A5.504.2 IAQ postconstruction. After all interior finishes have been installed, flush out the building by supplying continuous ventilation with all air handling units at their maximum outdoor air rate and all supply fans at their maximum position and rate for at least 14 days.
1. During this time, maintain an internal temperature of at least 60°F and relative humidity no higher than 60 percent.

CALGreen § 504.1 Medium relevance — show source text

504.1**Duct openings and other related air distribution component
openings shall be covered during construction.||||||| |4.504.2.1Adhesives, sealants and caulks shall be compliant with VOC
and other toxic compound limits.||||||| |4.504.2.2 Paints, stains and other coatings shall be compliant with
VOC limits.||||||| |4.504.2.3 Aerosol paints and coatings shall be compliant with
product weighted MIR limits for ROC and other toxic compounds.||||||| |4.504.2.4Documentation shall be provided to verify that compliant
VOC limit finish materials have been used.|
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| |4.504.3Carpet and carpet systems shall be compliant with VOC limits.||||||| |4.504.480 percent of floor area receiving resilient flooring shall
comply with specified VOC criteria.||||||| |4.504.5Particleboard, medium density fiberboard (MDF) and
hardwood plywood used in interior or exterior finish systems shall
comply with low formaldehyde emission standards.|||||||

APPENDIX A4-28 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

APPENDIX A4 — RESIDENTIAL VOLUNTARY MEASURES

SECTION A4.602—RESIDENTIAL OCCUPANCIES APPLICATION CHECKLIST—continued

FEATURE OR MEASURE	LEVELS APPLICANT TO SELECT ELECTIVE MEASURES	Col3	Col4	VERIFICATIONS ENFORCING AGENCY TO SPECIFY VERIFICATION METHOD	Col6	Col7
FEATURE OR MEASURE	Mandatory	Prerequisites and electives1	Prerequisites and electives1	Enforcing Agency  All	Installer or Designer  All	Third party  All
FEATURE OR MEASURE	Mandatory	Tier 1	Tier 2	Tier 2	Tier 2	Tier 2
A4.504.1Use composite wood products made with either California Air Resources Board approved no-added formaldehyde (NAF) resins or ultra-low emitting formaldehyde (ULEF) resins.						
A4.504.2Install VOC compliant resilient flooring systems. **Tier 1.

CALGreen § 3130B.1 Medium relevance — show source text
SECTION 3130B—DIATOMACEOUS EARTH FILTERS

In addition to the requirements for all filters as indicated in Section 3128B, the following applies to diatomaceous earth filters.

3130B.1 Flow rates. The filtration rate for both pressure and vacuum diatomaceous earth filters shall not exceed 2 gallons per minute per square foot (81.49 L/m per m [2] ) of filter area.

SECTION 3131B—HIGH-RATE SAND FILTERS

In addition to the requirements for all filters as indicated in Section 3128B, the following apply to high rate sand filters.

3131B.1 Flow rates. Maximum and minimum flow rates for backwash and filtration shall be maintained according to the applicable requirements established by the NSF/ANSI 50-2010 performance standard effective August 2010.

3131B.2 The filter media shall have an effective particle size between 0.40 and 0.55 mm and a uniformity coefficient not exceeding 1.75.

3131B.3 The backwash rate for a high rate sand filter shall be a minimum of 15 gallons per minute per square foot of filter area.

SECTION 3132B—CARTRIDGE FILTERS

In addition to the requirements for all filters as indicated in Section 3128B, the following apply to cartridge filters.

3132B.1 The filtration rate shall not exceed 0.375 gallons per minute per square foot of filter area.

3132B.2 An approved wash down area equipped with potable water shall be provided in the pool equipment area with permanently installed drainage piping discharging to the public sewer or wastewater system approved by the enforcing wastewater agency. The filter vessel shall be capable of being drained and shall be equipped with an indirect drain for the purpose of draining the entire contents of the filter vessel. Drainage and backwash piping shall be considered indirect waste and installed in accordance with the requirements of Chapter 8 of the California Plumbing Code.

3132B.3 An additional set of filter elements shall be available for installation while the existing filter elements are cleaned.

SECTION 3133B—CHEMICAL FEEDERS

All chemical feeders including disinfectant feeders and the auxiliary feeders used for solutions, slurries or solids, along with components such as pumps, strainers, tubing connections, tanks and injection fittings shall comply with the provisions of this section.

3133B.1 General design requirements. The chemical feeder equipment shall: 1. Be maintained and repaired according to manufacturers’ specifications; and 2. Be constructed with an adjustable output rate device to permit repeated adjustments without loss of output rate accuracy and adjusted by an automatic chemical monitoring and control system that regulates, at a minimum, pH and disinfectant; and 3. Meet the applicable requirements established by the NSF/ANSI 50-2012 performance standard effective September 2012.

3133B.2 Piping. Piping used for the chemical feeder and its auxiliary equipment shall be resistant to corrosion or chemical deterioration.

3133B.3 Installation. Chemical feeders and associated components shall be constructed and installed to prevent uncontrolled discharge or siphoning of chemicals and fumes directly into the pool, its recirculation system, the pool area or ancillary facilities.

2025 CALIFORNIA BUILDING CODE 31B-13

Frequently asked questions

What exactly is considered a "return air opening" for the construction filter requirement?

A: The code phrase refers to the HVAC system return inlets (grilles/ducts) where building air is drawn back to air handlers. When HVAC equipment is used during construction, those return openings must be fitted with filters rated MERV 8 or higher. § A4.506.2.

Do forced‑air furnaces installed in a conditioned closet count as "located in the conditioned space"?

A: Yes — if the equipment is within the conditioned envelope and not in an isolated mechanical room, the code requires the appliances be direct‑vent or the equipment relocated to an isolated mechanical room. § A4.506.3.

How do I prove resilient flooring or insulation compliance?

A: The code requires documentation that the materials are certified to meet CDPH 01350 or the stated pollutant emission limits. Collect manufacturer or third‑party certification tied to CDPH 01350. § A4.504.2 / § A4.504.3.

Is the CDPH 01350 numeric VOC table included in CALGreen?

A: No — CALGreen references the CDPH 01350 test method and requires compliance and documentation, but the specific numeric emission limits are in the CDPH 01350 standard and are not reproduced in the retrieved CALGreen excerpts. § A4.504.2 / § A4.504.3.

If I install MERV 8 filters during construction, do I need to keep them in place after occupancy?

A: The code snippet specifies MERV 8 filters during construction; it doesn't mandate permanent filter class for post‑occupancy in these sections. Check the mechanical and maintenance sections or local energy/IAQ requirements for long‑term filtration standards. § A4.506.2.

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California Green Building Standards Code (CALGreen)