CALGreen · California Green Building Standards Code (CALGreen)

Which TAB (testing/adjusting/balancing) standards does CALGreen reference for HVAC verification?

CALGreen (see **§ 5.410.4.3.1**) requires HVAC systems to be tested, adjusted and balanced using one of three nationally recognized TAB procedures — **TABB**, **NEBB**, or **AABC** — (or an alternative approved by the enforcing agency) and that balancing be completed before the system is placed into normal operation; a final signed testing report is also required.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

CALGreen requires that HVAC systems be balanced using established TAB standards before the system is placed into normal operation. The controlling provision is § 5.410.4.3.1 — which directs balancing be performed “in accordance with the procedures defined by the Testing Adjusting and Balancing Bureau National Standards; the National Environmental Balancing Bureau Procedural Standards; Associated Air Balance Council National Standards or as approved by the enforcing agency.” § 5.410.4.3 also requires testing and adjusting procedures to follow manufacturer specifications and applicable standards.

Balance HVAC systems to one of the nationally recognized TAB procedures (TABB, NEBB, or AABC) — or use an enforcing-agency‑approved alternative — and do it before the system is operated for normal use. § 5.410.4.3.1

Requirements in detail

Short summary of the clause

The code requires HVAC balancing in addition to ordinary testing and adjusting; balancing must be done before a new space-conditioning system is operated for normal use. § 5.410.4.3.1
Testing and adjusting work generally must follow the manufacturer’s specifications and applicable standards. § 5.410.4.3
After completion, provide a final, signed testing report by the person who performed the services. § 5.410.4.4

Decision-relevant dimensions and values

Decision dimension	Requirement / value	Code Reference
Which TAB standards may be used	Testing Adjusting and Balancing Bureau (TABB) National Standards; National Environmental Balancing Bureau (NEBB) Procedural Standards; Associated Air Balance Council (AABC) National Standards — or a standard approved by the enforcing agency	§ 5.410.4.3.1
When balancing must be completed	Before a new space-conditioning system serving a building or space is operated for normal use	§ 5.410.4.3.1
What the TAB work must follow	Manufacturer’s specifications and applicable standards for each system	§ 5.410.4.3
Documentation required	Final report of testing signed by the individual responsible for performing testing/adjusting/balancing	§ 5.410.4.4
Where referenced standards are listed	CALGreen reference list identifies NEBB, TABB and AABC in the referenced-standards table (entry for § 5.410.4.3.1)	Appendix / Referenced Organizations & Standards table (see referenced entries for NEBB, TABB, AABC)

Notes about the named organizations

The code text names the full descriptions (e.g., “Testing Adjusting and Balancing Bureau National Standards,” “National Environmental Balancing Bureau Procedural Standards,” and “Associated Air Balance Council National Standards”) — CALGreen does not embed the procedural text of those standards; it references them as the acceptable procedures. § 5.410.4.3.1
The referenced‑standards list in the code’s appendix includes entries for NEBB, TABB and AABC associated with this section.

Exceptions & special cases

The clause permits use of “as approved by the enforcing agency” as an alternative to the three named national standards. That means local authorities having jurisdiction (AHJ) may accept equivalent test procedures or certification programs when approved. § 5.410.4.3.1
CALGreen’s requirement is tied into the smaller‑building testing scope: testing and adjusting are explicitly required for new buildings less than 10,000 square feet or new systems that serve additions/alterations (see the broader section 5.410.4). If your project falls under other codes (e.g., California Energy Code commissioning/testing requirements), you must follow those additional rules as noted in the CALGreen cross-reference. § 5.410.4; § 5.410.4.1 (note)

Common mistakes

Assuming any in‑house or generic TAB checklist meets CALGreen — the code requires balancing to follow one of the named national standards or an enforcing‑agency‑approved equivalent (§ 5.410.4.3.1).
Waiting until after the system is in normal operation to perform TAB. The balancing step must be completed before normal operation. § 5.410.4.3.1
Forgetting the paperwork: CALGreen requires a final, signed testing report after completion. § 5.410.4.4
Misreading the referenced standards list: CALGreen references the standards by name but does not reproduce their procedures — you must obtain and follow the current edition of the chosen standard or obtain AHJ approval for an equivalent.

Worked example — a concrete scenario applying the rule

Scenario: A tenant builds out a 7,500 ft² office inside a larger building and installs a new packaged rooftop HVAC system with VAV boxes that serves that space.

Applicability: Testing and adjusting is required for this new system because it is a new system serving an addition/alteration and the project is under 10,000 ft² (see § 5.410.4 scope).
TAB action: Before the system is operated for normal use the contractor hires a TAB firm to perform balancing in accordance with NEBB Procedural Standards (or TABB/AABC — the owner chose NEBB). This satisfies § 5.410.4.3.1.
Documentation: The TAB firm produces a final report containing the measurements, adjustments, and the signature of the individual responsible for the TAB work — that report is submitted to the building owner and the enforcing agency as required by § 5.410.4.4.
If the AHJ required a different nationally recognized standard or had an approved in‑house protocol, the TAB firm would follow that instead (per the “or as approved by the enforcing agency” allowance). § 5.410.4.3.1

Related provisions

§ 5.410.4 — Testing and adjusting (scope and requirement for new buildings < 10,000 ft²).
§ 5.410.4.3 — Procedures: testing and adjusting must follow manufacturer specs and applicable standards.
§ 5.410.4.4 — Reporting: final signed testing report required after completion.
§ 5.410.2.6 — Commissioning report (related commissioning activities and documentation).
Appendix / Referenced Standards entries for NEBB, TABB, AABC (shows those organizations as the intended references for § 5.410.4.3.1).

Code references

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

CALGreen § 5.410.2.5 High relevance — show source text
4**
Material
Conservation
and Resource
Efficiency|Mandatory|Documentation and training [N]|5.410.2.5||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Systems manual [N]|5.410.2.5.1||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Systems operation training [N]|5.410.2.5.2||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Commissioning report [N]|5.410.2.6||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Testing and adjusting for new buildings < 10,000 sf or
new systems that serve additions or alterations [A]|5.410.4||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|System testing plan for renewable energy, landscape
irrigation and water reuse [A]|5.410.4.2||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Procedures for testing and adjusting|5.410.4.3||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Procedures for HVAC balancing|5.410.4.3.1||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Reporting for testing and adjusting|5.410.4.4||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Operation and maintenance (O&M) manual|5.410.4.5||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Inspection and reports|5.410.4.5.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Fireplaces|5.503.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Woodstoves|5.503.1.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Temporary ventilation|5.504.
CALGreen § 2.5.2 High relevance — show source text
2.5.2||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Commissioning report [N]|5.410.2.6||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Testing and adjusting for new buildings < 10,000 sf or
new systems that serve additions or alterations [A]|5.410.4||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|System Testing Plan for renewable energy, landscape
irrigation and water reuse [A]|5.410.4.2||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Procedures for testing and adjusting|5.410.4.3||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Procedures for HVAC balancing|5.410.4.3.1||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Reporting for testing and adjusting|5.410.4.4||||| |(continued)
**DIVISION 5.

CALGreen § 5.410.4.3 High relevance — show source text

Water reuse systems.

5.410.4.3 Procedures. Perform testing and adjusting procedures in accordance with manufacturer's specifications and applicable standards on each system.

5.410.4.3.1 HVAC balancing. In addition to testing and adjusting, before a new space-conditioning system serving a building or space is operated for normal use, balance the system in accordance with the procedures defined by the Testing Adjusting and Balancing Bureau National Standards; the National Environmental Balancing Bureau Procedural Standards; Associated Air Balance Council National Standards or as approved by the enforcing agency.

5.410.4.4 Reporting. After completion of testing, adjusting and balancing, provide a final report of testing signed by the individual responsible for performing these services.

5.410.4.5 Operation and maintenance (O & M) manual. Provide the building owner or representative with detailed operating and maintenance instructions and copies of guaranties/warranties for each system. O & M instructions shall be consistent with OSHA requirements in CCR, Title 8, Section 5142, and other related regulations.

5.410.4.5.1 Inspections and reports. Include a copy of all inspection verifications and reports required by the enforcing

agency.

5-28 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

CALIFORNIA GREEN BUILDING STANDARDS CODE – MATRIX ADOPTION TABLE

CHAPTER 5 – NONRESIDENTIAL MANDATORY MEASURES

DIVISION 5.5 – ENVIRONMENTAL QUALITY

(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

Adopting agency	BSC	BSC- CG	SFM	HCD	Col6	Col7	DSA	Col9	OSHPD	Col11	Col12	Col13	Col14	Col15	BSCC	DPH	AGR	DWR	CEC	CA	SL	SLC
Adopting agency	BSC	BSC- CG	SFM	1	2	1/AC	AC	SS	1	1R	2	3	4	5	5	5	5	5	5	5	5	5
Adopt entire CA chapter		X
Adopt entire chapter as amended (amended sections listed below)
Adopt only those sections that are listed below								X
Chapter/Section
5.501.1								X
5.502.1 Definitions								X
5.504.3								X
5.504.4								X
5.504.4.1								X
Table 5.504.4.1								X
Table 5.

CALGreen § 5.410.4.2 High relevance — show source text
landscape
irrigation and water reuse [A]|5.410.4.2||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Procedures for testing and adjusting|5.410.4.3||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Procedures for HVAC balancing|5.410.4.3.1||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Reporting for testing and adjusting|5.410.4.4||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Operation and maintenance (O&M) manual|5.410.4.5||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Mandatory|Inspection and reports|5.410.4.5.1||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Select One Elective|Elective|Wood framing or OVE w/ note|A5.404.1,
A5.404.1.1,
A5.404.1.2||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select One Elective|Select One Elective|Elective|Regional materials|_A5.405.
CALGreen § 5.410.2.5.2 High relevance — show source text
4**
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|Mandatory|Systems operation training [N]|5.410.2.5.2||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|Mandatory|Commissioning report [N]|5.410.2.6||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|Mandatory|Testing and adjusting for new buildings < 10,000 sf or
new systems that serve additions or alterations [A]|5.410.4||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|Mandatory|System Testing Plan for renewable energy, landscape
irrigation and water reuse [A]|5.410.4.2||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|Mandatory|Procedures for testing and adjusting|5.410.4.3||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|Mandatory|Procedures for HVAC balancing|5.410.4.3.1||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency
Select Three Electives
(cont’d)|(continued)
**DIVISION 5.
CALGreen § 5.410.2.6 High relevance — show source text
5.410.2.6 Commissioning report. [N] A report of commissioning process activities undertaken through the design and construction phases of the building project shall be completed and provided to the owner or representative.

5.410.3 Reserved.

5.410.4 Testing and adjusting. New buildings less than 10,000 square feet. Testing and adjusting of systems shall be required for new buildings less than 10,000 square feet or new systems to serve an addition or alteration subject to Section 303.1.

5.410.4.1 Reserved.

Note: For energy-related systems under the scope (Section 100) of the California Energy Code, including heating, ventilation, air conditioning (HVAC) systems and controls, indoor lighting system and controls, as well as water heating systems and controls, refer to California Energy Code Section 120.8 for commissioning requirements and Sections 120.5, 120.6, 130.4 and 140.9(b)3 for additional testing requirements of specific systems.

5.410.4.2 Systems. Develop a written plan of procedures for testing and adjusting systems. Systems to be included for testing and adjusting shall include, as applicable to the project:
1. Renewable energy systems.
2. Landscape irrigation systems.
3. Water reuse systems.
5.410.4.3 Procedures. Perform testing and adjusting procedures in accordance with manufacturer's specifications and applicable standards on each system.

5.410.4.3.1 HVAC balancing. In addition to testing and adjusting, before a new space-conditioning system serving a building or space is operated for normal use, balance the system in accordance with the procedures defined by the Testing Adjusting and Balancing Bureau National Standards; the National Environmental Balancing Bureau Procedural Standards; Associated Air Balance Council National Standards or as approved by the enforcing agency.

5.410.4.4 Reporting. After completion of testing, adjusting and balancing, provide a final report of testing signed by the individual responsible for performing these services.

5.410.4.5 Operation and maintenance (O & M) manual. Provide the building owner or representative with detailed operating and maintenance instructions and copies of guaranties/warranties for each system. O & M instructions shall be consistent with OSHA requirements in CCR, Title 8, Section 5142, and other related regulations.

5.410.4.5.1 Inspections and reports. Include a copy of all inspection verifications and reports required by the enforcing

agency.

5-28 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

CALIFORNIA GREEN BUILDING STANDARDS CODE – MATRIX ADOPTION TABLE

CHAPTER 5 – NONRESIDENTIAL MANDATORY MEASURES

DIVISION 5.5 – ENVIRONMENTAL QUALITY

(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
CALGreen § 410.4.3 High relevance — show source text
410.4.3||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Procedures for HVAC balancing|5.410.4.3.1||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Reporting for testing and adjusting|5.410.4.4||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Operation and maintenance (O&M) manual|5.410.4.5||||| |(continued)
DIVISION 5.4
Material
Conservation
and Resource
Efficiency|Mandatory|Inspection and reports|5.410.4.5.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Fireplaces|5.503.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Woodstoves|5.503.1.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Temporary ventilation|5.504.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Covering of ducts openings and protection of mechani-
cal equipment during construction|5.504.3||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Adhesives, sealants and caulks|5.504.4.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Paints and coatings|5.504.4.3||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Aerosol paints and coatings|5.504.4.3.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Aerosol paints and coatings: verification|5.504.4.3.2||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Carpet systems|5.504.4.4||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Carpet cushion|5.504.4.4.1||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Carpet adhesives per Table 5.504.4.1|5.504.4.4.2||||| |DIVISION 5.5
Environmental
Quality
(continued)|Mandatory|Composite wood products|5.504.4.
CALGreen § 25.4 High relevance — show source text
For SI units: 1 inch = 25.4 mm

313.7 Gas Piping. Gas piping shall be supported by metal straps or hooks at intervals not to exceed those shown in Table 1310.3.5.1.

314.0 Balancing.

314.1 General. Heating, ventilating, and air-conditioning systems (including hydronic systems) shall be balanced in accordance with one of the following methods:

TABLE 313.6

HANGER ROD SIZES

(1) AABC National Standards for Total System Balance

(2) ACCA Manual B

(3) ASHRAE 111

(4) NEBB Procedural Standards for Testing Adjusting Balancing of Environmental Systems

(5) SMACNA HVAC Systems Testing, Adjusting, and Balancing

315.0 Louvers in Hurricane Prone Regions.

315.1 General. Louvers located in areas within hurricane prone regions that are within 1 mile (2 km) of the coastal mean high water line where the basic wind speed is 110 miles per hour (mi/h) (49.2 m/s) or more; or portions of hurricane-prone regions where the basic wind speed is 120 mi/h (53.6 m/s) or more; or Hawaii, shall be tested in accordance with Section 315.1.1 and Section 315.1.2.

315.1.1 Testing. Louvers that protect air intake or exhaust openings shall be tested in accordance with AMCA 550 for resistance to wind-driven rain.

315.1.2 Impact Resistance Test. Upon request by the Authority Having Jurisdiction, louvers protecting intake and exhaust ventilation ducts that are not fixed in the

open position and located within 30 feet (9144 mm) of the grade shall be tested for impact resistance in accordance with AMCA 540.

316.0 Protection of Piping, Tubing, Materials, and Structures.

316.1 General. Piping or tubing passing under or through walls shall be protected from breakage. Piping passing through or under cinders or other corrosive materials shall be protected from external corrosion in an approved manner. Approved provisions shall be made for expansion of hot water piping. Voids around piping or tubing passing through concrete floors on the ground shall be sealed.

316.2 Installation. Piping or tubing shall be installed so that the piping, tubing, or connections will not be subject to undue strains or stresses, and provisions shall be made for expansion, contraction, and structural settlement. No piping or tubing, unless designed and listed for such use, shall be directly embedded in concrete or masonry. No structural member shall be seriously weakened or impaired by cutting, notching, or otherwise as defined in the California Building Code or California Residential Code .

316.3 Corrosion, Erosion, and Mechanical Damage. Piping or tubing subject to corrosion, erosion, or mechanical damage shall be protected in an approved manner.

316.4 Protectively Coated Pipe. Protectively coated pipe or tubing shall be inspected and tested, and a visible void, damage, or imperfection to the pipe coating shall be repaired in an approved manner.

316.5 Fire-Resistant Construction. Piping, tubing, and duct system penetrations of fire-resistance-rated walls, parti

For SI units: 1 inch = 25.4 mm

2025 CALIFORNIA MECHANICAL CODE 59
CALGreen § 312.0 High relevance — show source text
312.0 Plumbing Connections. 312.1 General. Water supply, sanitary drainage, and backflow protection shall be in accordance with the California Plumbing Code .

313.0 Hangers, Supports, and Anchors. 313.1 General. Piping, tubing, appliances, and appurtenances shall be supported in accordance with this code, the manufacturer’s installation instructions, and in accordance with the Authority Having Jurisdiction. Seismic restraints shall be in accordance with the building code. 313.2 Material. Hangers, supports, and anchors shall be of sufficient strength to support the weight of the pipe or tubing and its contents. Piping or tubing shall be isolated from incompatible materials.

313.3 Suspended Piping. Suspended piping or tubing shall be supported at intervals not to exceed those shown in Table 313.3.

313.4 Alignment. Piping or tubing shall be supported in such a manner as to maintain its alignment and prevent sagging.

313.5 Underground Installation. Piping or tubing in the ground shall be laid on a firm bed for its entire length; where other support is otherwise provided, it shall be approved in accordance with Section 302.0.

313.6 Hanger Rod Sizes. Hanger rod sizes shall be not smaller than those shown in Table 313.6.

TABLE 313.6

HANGER ROD SIZES

PIPE AND TUBE SIZE
(inches) ROD SIZES
(inches)

1⁄2 - 4 3⁄8

5 - 8 1⁄2

10 - 12 5⁄8

For SI units: 1 inch = 25.4 mm

313.7 Gas Piping. Gas piping shall be supported by metal straps or hooks at intervals not to exceed those shown in Table 1310.3.5.1.

314.0 Balancing.

314.1 General. Heating, ventilating, and air-conditioning systems (including hydronic systems) shall be balanced in accordance with one of the following methods:

TABLE 313.6

HANGER ROD SIZES

(1) AABC National Standards for Total System Balance

(2) ACCA Manual B

(3) ASHRAE 111

(4) NEBB Procedural Standards for Testing Adjusting Balancing of Environmental Systems

(5) SMACNA HVAC Systems Testing, Adjusting, and Balancing

315.0 Louvers in Hurricane Prone Regions.

315.1 General. Louvers located in areas within hurricane prone regions that are within 1 mile (2 km) of the coastal mean high water line where the basic wind speed is 110 miles per hour (mi/h) (49.2 m/s) or more; or portions of hurricane-prone regions where the basic wind speed is 120 mi/h (53.6 m/s) or more; or Hawaii, shall be tested in accordance with Section 315.1.1 and Section 315.1.2.

315.1.1 Testing. Louvers that protect air intake or exhaust openings shall be tested in accordance with AMCA 550 for resistance to wind-driven rain.

315.1.2 Impact Resistance Test. Upon request by the Authority Having Jurisdiction, louvers protecting intake and exhaust ventilation ducts that are not fixed in the
CALGreen § 0.65 High relevance — show source text
Duct leakage tests shall be performed by a technician certified by the Associated Air Balance Council (AABC), the National Environmental Balancing Bureau (NEBB), the Testing, Adjusting and Balancing Bureau (TABB), or other equivalent approved agencies. Representative sections totaling not less than 10 percent of the total installed duct area shall be tested. Where the tested 10 percent fail to comply with the requirements of this section, then 40 percent of the total installed duct area shall be tested. Where the tested 40 percent fail to comply with the requirements of this section, then 100 percent of the total installed duct area shall be tested. Sections shall be selected by the building owner or designated representative of the building owner. Positive pressure leakage testing shall be permitted for negative pressure ductwork. The permitted duct leakage shall be not more than the following:

Lmax = CLP [0.65 ] (Equation 603.9.2)

Where:

Lmax = maximum permitted leakage, (ft [3] /min)/100 square feet [0.0001 (m [3] /s)/m [2] ] duct surface

area.

CL = six, duct leakage class, (ft [3] /min)/100 square feet [0.0001 (m [3] /s)/m [2] ] duct surface area at 1 inch water column (0.2 kPa).

P = test pressure, which shall be equal to the design duct pressure class rating, inch water column (kPa).

Exception: Transfer air duct operating at less than 1 inch of water column (0.25 kPa). 603.9.2.1 Duct Leakage Tests for Buildings that Meet Air Distribution System Duct Leak- age Sealing Criteria in Title 24, Part 6. For duct leakage testing, see California Energy Code Sec- tions 150.0(m)(11) for single family buildings, Sec- tion 160.3(b) for multifamily buildings, and Section 120.4(g) for nonresidential and Hotel Motel build- ings. 603.10 Cross Contamination. Exhaust ducts that convey Class 4 air shall be negatively pressurized relative to ducts, plenums, or occupiable spaces through which the ducts pass. Exhaust ducts under positive pressure that convey Class 2 or Class 3 air shall not extend into or pass through ducts, plenums, or occupiable spaces other than the space from which the exhaust air is drawn.

603.11 Underground Installation. Ducts installed underground shall be approved for the installation and shall have a slope of not less than [1] ⁄ 8 inch per foot (10.4 mm/m) back to the main riser. Ducts, plenums, and fittings shall be permitted to be constructed of concrete, clay, or ceramics where installed in the ground or in a concrete slab, provided the joints are sealed and duct is secured in accordance with SMACNA

HVAC Duct Construction Standards – Metal and Flexible.

Metal ducts where installed in or under a concrete slab shall be encased in not less than 2 inches (51 mm) of concrete, secured in accordance with SMACNA HVAC Duct Con struction Standards – Metal and Flexible.

PIPE AND TUBE SIZE (inches)	ROD SIZES (inches)
1⁄2 - 4	3⁄8
5 - 8	1⁄2
10 - 12	5⁄8

CALGreen § 21.7 High relevance — show source text

kBtu/h [ (Line # 1b) x 21.7 ft3/min/kBtu/h].||| |3.|Total calculated supply fan flow 2(a) or 2(b) ft3/min.|||

NEW CONSTRUCTION OR ENTIRE NEW DUCT SYSTEM ALTERATION:	Col2	Col3	Col4
	Duct pressurization test results (ft3/min @ 25 Pa).	Duct pressurization test results (ft3/min @ 25 Pa).	Duct pressurization test results (ft3/min @ 25 Pa).
4.	Enter tested leakage flow in ft3/min:		P P
5.	Pass if leakage percentage≤6%: [( Line #4)/(Line #3 )] x 100	%	 Pass Fail
ALTERATIONS: Pre-existing duct system with duct alteration and/or HVAC equipment change-out.	ALTERATIONS: Pre-existing duct system with duct alteration and/or HVAC equipment change-out.	ALTERATIONS: Pre-existing duct system with duct alteration and/or HVAC equipment change-out.	ALTERATIONS: Pre-existing duct system with duct alteration and/or HVAC equipment change-out.
6.	Enter tested leakage flow (cubic feet per minute): Pre-test of existing duct system prior to duct system alteration, equipment change-out, or both.
7.	Enter tested leakage flow (cubic feet per minute): Final test of new duct system or altered duct system for duct system alteration, equipment change-out, or both.
TEST OR VERIFICATION STANDARDS: For altered duct system and/or HVAC equipment change-out use one of the following three tests or verification standards for compliance:	TEST OR VERIFICATION STANDARDS: For altered duct system and/or HVAC equipment change-out use one of the following three tests or verification standards for compliance:	TEST OR VERIFICATION STANDARDS: For altered duct system and/or HVAC equipment change-out use one of the following three tests or verification standards for compliance:	TEST OR VERIFICATION STANDARDS: For altered duct system and/or HVAC equipment change-out use one of the following three tests or verification standards for compliance:
8.	Pass if leakage percentage <15% [ (Line # 7) / (Line # 3 )] x 100	%	 Pass Fail
9.	Pass if leakage reduction percentage >60% Leakage reduction = [1 - [ (Line#7) / (Line#6 )] } x 100	%	 Pass Fail
10.	Pass if all accessible leaks are sealed as confirmed by visual inspection and verifica- tion by HERS rater (sampling rate 100%).	%	 Pass Fail
	Pass if One of Lines #8 through #10 pass		 Pass Fail

For SI units: 1000 British thermal units per hour = 0.293 kW, 1 cubic foot per minute = 0.00047 m [3] /s, 1 metric ton = 1000 kg

2025 CALIFORNIA MECHANICAL CODE 501

APPENDIX E

Frequently asked questions

Who can perform the TAB work required by CALGreen?

CALGreen itself does not specify a required credential in § 5.410.4.3.1; it requires balancing to be performed in accordance with one of the named standards (TABB, NEBB, AABC) or as approved by the enforcing agency. Many AHJs or project specifications require a technician certified by NEBB, TABB, AABC, or equivalent — check the AHJ and project documents.

Do I need to buy the NEBB/TABB/AABC standard text to comply?

CALGreen references those standards by name for procedural compliance; to apply them correctly you or your TAB provider will generally need access to the current procedural standard text or an AHJ‑approved alternative. The code does not reproduce the standard content.

If the AHJ approves an alternate standard, is that documented in CALGreen?

Yes — § 5.410.4.3.1 explicitly allows balancing “or as approved by the enforcing agency,” so an AHJ‑approved equivalent procedure is permitted. § 5.410.4.3.1

Is TAB required for duct leakage testing under CALGreen?

CALGreen’s § 5.410.4.3.1 is about balancing procedures and references national TAB standards; specific duct leakage test procedures and sampling may also be governed by the California Mechanical Code and the California Energy Code (cross‑references exist). Check the Mechanical and Energy Code provisions for detailed leakage test requirements.

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