Title 24 · California Energy Code
What are the requirements and tests for supply‑fan variable‑flow controls?
Before occupancy, California’s Energy Code requires supply‑fan variable‑flow controls to be acceptance‑tested (per NA7.5.6 / MECH‑7A). The test verifies the fan (VFD) can modulate up/down, hold duct discharge static pressure within ±10% of the setpoint, stabilize within 5 minutes, operate down to at least 30% of design flow, and use calibrated pressure sensors; results are recorded on a Certificate of Acceptance and submitted to the jurisdiction.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Before a final occupancy permit is issued, supply‑fan variable‑flow controls must be functionally tested and certified per the acceptance‑test requirements referenced in § 120.5. The Energy Code directs that these systems be tested in accordance with NA7.5.6 (the Nonresidential Appendix acceptance test for supply‑fan variable flow controls) and a Certificate of Acceptance must be submitted to the enforcement agency prior to occupancy. § 120.5 also ties acceptance testing and who may perform it to the CMATT certification rules when Title 24 Part 1 requires certification.
Before occupancy, the supply fan VFD and control strategy must be demonstrated to modulate airflow up and down, hold the duct static pressure within tolerance, and stabilize — per NA7.5.6 as required by § 120.5.
Requirements in detail
Scope and controlling citations (first mention)
- The mandatory acceptance testing requirement is from § 120.5 (see list of required tests; supply‑fan variable flow controls are item 6).
- The test procedure / acceptance criteria used for the field test are those in NA7.5.6 (see Title 24 NA7) and the mechanically equivalent test procedures/forms in Appendix E (MECH‑7A / E 805.7) of the 2025 Mechanical Code.
What must be demonstrated (decision‑relevant values)
The test procedure and acceptance criteria require evidence of the following measurable behaviors. The table below collects the decision‑critical thresholds you will be judged on during acceptance testing:
| Decision dimension | Requirement / threshold | Code Reference |
|---|---|---|
| Test before occupancy | Acceptance test and Certificate of Acceptance submitted prior to issuing occupancy | § 120.5 |
| Test standard to use | Perform test in accordance with NA7.5.6 (Title 24 NA7) — MECH‑7A / E 805.7 provides the test steps and form | NA7.5.6 and E 805.7 (MECH‑7A) |
| Static pressure control accuracy | Maintain discharge static pressure within ±10% of the current operating setpoint during test conditions | E 805.7 / Functional test steps |
| Control stabilization time | Supply‑fan controls must stabilize within 5 minutes after a change in demand | E 805.7 / Construction inspection & functional testing steps |
| Minimum flow condition | Minimum flow for test not less than 30% of total design flow (minimum flow condition requirement) | E 805.7 acceptance checks (minimum flow) |
| Pressure sensor calibration | Static pressure sensor(s) must be factory calibrated (with certificate) or field calibrated | E 805.7.2 Acceptance Criteria |
| Pressure‑setpoint strategy (non‑DDC) | For systems without DDC to the zone level, the pressure sensor setpoint must be less than one‑third of the supply fan design static pressure | E 805.7.2 Acceptance Criteria |
| Pressure‑setpoint strategy (DDC with VAV boxes) | For systems with DDC and VAV boxes reporting to central control, the pressure setpoint must be reset by zone demand (e.g., box damper position or trim & respond algorithm) | E 805.7.2 Acceptance Criteria |
| Demonstrate up/down modulation | Under simulated design airflow and minimum airflow demands, the supply fan controls must modulate up and modulate down respectively and show setpoint changes where applicable | E 805.7 functional Steps 1–3 (drive VAV boxes to design and minimum flows) |
(See form MECH‑7A / E 805.7 for the checklist and places to record results.)
Test procedure (overview of steps)
- Construction inspection: verify sensors installed and calibrated and that controls can modulate the fan/VFD (E 805.7.1.1).
- Functional testing (high level):
- Step 1 — simulate design airflow (drive VAV boxes to call for design). Verify controls increase capacity, static pressure maintained ±10%, stabilize within 5 minutes.
- Step 2 — simulate minimum airflow (drive VAV boxes to minimum). Verify controls decrease capacity, setpoint reduces (if DDC), static pressure within ±10%, stabilize within 5 minutes.
- Step 3 — restore normal operation and document test results on the Certificate of Acceptance (MECH‑7A).
Exceptions & special cases
- Systems serving healthcare facilities are excepted from Section 120.5 acceptance requirements (check the exceptions in § 120.5). If the system serves a healthcare facility, NA7.5.6 may not apply.
- For air economizers and some factory‑tested units, the Energy Code includes separate exceptions; these do not directly change the supply‑fan variable flow control test but may affect whether other tests are required. See the exceptions to §120.5(a)4 for the related economizer rules.
- When Title 24, Part 1 requires certification, a Certified Mechanical Acceptance Test Technician (CMATT) or employer requirements apply — the acceptance testing must be performed by a CMATT as specified by the Part 1 rules.
If your project has special controls (e.g., alternative sensor locations, unusual VAV strategies), consult NA7.5.6 text and the MECH‑7A form for allowable approaches — the Mechanical Appendix language documents acceptable setpoint reset methods for DDC systems.
Common mistakes
- Assuming a signed test report alone is sufficient — the Certificate of Acceptance must show the system meets NA7.5.6 and be submitted before issuance of final occupancy per § 120.5.
- Using an uncalibrated or undocumented pressure sensor — sensors must be factory‑calibrated with certificate or field‑calibrated and within tolerance. Testers often forget to attach calibration evidence.
- Wrong setpoint strategy: for non‑DDC systems the setpoint must be less than one‑third of design static pressure — setting a much higher control setpoint defeats the turndown intent.
- Not demonstrating both design and minimum flow conditions (including the ≥30% design flow minimum); sometimes only the full flow condition is shown. The NA7/E805.7 test requires both.
- Failure to have the test performed or signed by an appropriately certified person when CMATT rules apply (Title 24 Part 1 references).
Worked example — concrete scenario
Scenario: central AHU serving VAV boxes, design discharge static pressure = 3.0 in. w.c., design supply airflow = 20,000 cfm, system has only central pressure sensor (no zone‑level DDC).
Step through the acceptance checks:
- Sensor calibration — provide factory calibration certificate or perform field calibration and record results. E 805.7 requires calibrated sensors.
- Pressure setpoint for this non‑DDC system must be less than one‑third of design static pressure: 3.0 in. w.c. ÷ 3 = 1.0 in. w.c. → choose setpoint < 1.0 in. w.c. to meet the criterion.
- Full‑flow test (simulate design airflow): supply fan must maintain discharge static pressure within ±10% of the setpoint. If setpoint 0.95 in. w.c., allowable band is 0.855 – 1.045 in. w.c. Fan controls must stabilize within 5 minutes after driving boxes to design. Record Y/N on MECH‑7A.
- Minimum‑flow test (simulate box minimums): minimum flow requirement is not less than 30% of design flow → 0.30 × 20,000 = 6,000 cfm. Drive boxes to minimum and show the supply fan modulates down; the fan must maintain static pressure within ±10% of the new operating setpoint and stabilize within 5 minutes.
- Complete and submit the Certificate of Acceptance (MECH‑7A) to the AHJ before occupancy.
Related provisions
- § 120.5 — Required nonresidential mechanical system acceptance (lists NA7.5.6 for supply fan variable flow controls).
- NA7.5.6 — Reference Nonresidential Appendix acceptance test for supply‑fan variable flow controls (test standard to be used).
- E 805.7 / MECH‑7A (Mechanical Code Appendix E) — detailed test procedure and Certificate of Acceptance form used in the field (construction inspection, functional steps, acceptance criteria).
- § 10‑103.2 (Title 24 Part 1) and CMATT rules — when certification is required, tests must be performed by a certified technician/employer per Part 1 rules.
If you need the exact NA7.5.6 wording or the printed MECH‑7A form for sign‑off, consult the Title 24 Nonresidential Appendix NA7 and Mechanical Appendix E (MECH‑7A) supplied with the code; the Mechanical Appendix contains the operational checklist used in the field.
Code references
Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:
§ 5.6. High relevance — show source text
Supply fan variable flow controls shall be tested in accordance with NA7.5.6.
Hydronic system variable flow controls shall be tested in accordance with NA7.5.7 and NA7.5.9.
Boiler or chillers that require isolation controls as specified by Section 140.4(k)2 or 140.4(k)3 shall be tested in accordance with NA7.5.7.
Hydronic systems with supply water temperature reset controls shall be tested in accordance with NA7.5.8.
Automatic demand shed controls shall be tested in accordance with NA7.5.10.
Fault Detection and Diagnostics (FDD) for Packaged Direct-Expansion Units shall be tested in accordance with NA7.5.11.
Automatic fault detection and diagnostics (FDD) for air handling units and zone terminal units shall be tested in accordance with NA7.5.12.
Distributed Energy Storage DX AC Systems shall be tested in accordance with NA7.5.13.
Thermal Energy Storage (TES) Systems shall be tested in accordance with NA7.5.14.
Supply air temperature reset controls shall be tested in accordance with NA7.5.15.
Water-cooled chillers served by cooling towers with condenser water reset controls shall be tested in accordance with NA7.5.16.
When an energy management control system is installed, it shall functionally meet all of the applicable requirements of Part 6.
Occupant sensing zone controls shall be tested in accordance with NA7.5.17.
Conductivity controls and overflow alarms for open and closed-circuit cooling towers shall be tested according to NA7.5.18.
(b) When certification is required by Title 24, Part 1, Section 10-103.2, the acceptance testing specified by Section 120.5(a) shall be performed by a certified mechanical acceptance test technician (CMATT). If the CMATT is operating as an employee, the CMATT shall
2025 CALIFORNIA ENERGY CODE 79
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
NONRESIDENTIAL, HOTEL/MOTEL OCCUPANCIES, AND COVERED PROCESSES—MANDATORY REQUIREMENTS
be employed by a certified mechanical acceptance test employer. The CMATT shall disclose on the certificate of acceptance a valid CMATT certification identification number issued by an approved acceptance test technician certification provider. The CMATT shall complete all certificate of acceptance documentation in accordance with the applicable requirements in Section 10-103(a)4.
Note: Authority cited: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25007, 25008, 25218.5, 25310, 25402(a)-(b), 25402.1, 25402.4, 25402.5, 25402.8 and 25943, Public Resources Code .
SECTION 120.6—MANDATORY REQUIREMENTS FOR COVERED PROCESSES
Nonresidential and hotel/motel buildings shall comply with the applicable requirements of Sections 120.6(a) through 120.6(k), and the applicable requirements of Sections 110.2(a) and 120.3.
(a) Mandatory requirements for refrigerated warehouses.
§ 5.1. High relevance — show source text
(a) Before an occupancy permit is granted, the following equipment and systems shall be certified as meeting the Acceptance Requirements for Code Compliance, as specified by the Reference Nonresidential Appendix NA7. A Certificate of Acceptance shall be submitted to the enforcement agency that certifies that the equipment and systems meet the acceptance requirements:
Outdoor air ventilation systems shall be tested in accordance with NA7.5.1.
Constant volume, single zone unitary air conditioning and heat pump unit controls shall be tested in accordance with NA7.5.2.
Duct systems that are subject to testing under Section 120.4(g)1, Section 141.0(b)2Di or Section 141.0(b)2Dii shall be tested in accordance with NA7.5.3.
Air economizers, DOAS, HRV or ERV systems shall be tested in accordance with NA7.5.4. Exception 1 to Section 120.5(a)4: Air economizers installed by the HVAC system manufacturer and certified to the Commission as being factory calibrated and tested are not required to comply with the Functional Testing section of the air economizer controls acceptance test as described in NA7.5.4.2. Exception 2 to Section 120.5(a)4: The DOAS, HRV, or ERV unit that does not meet the exhaust air heat recovery ratio as specified in Section 140.4(q)1 or does not include bypass or control to disable energy recovery as specified in Section 140.4(q)2.
Demand control ventilation systems required by Section 120.1(c)3 shall be tested in accordance with NA7.5.5.
Supply fan variable flow controls shall be tested in accordance with NA7.5.6.
Hydronic system variable flow controls shall be tested in accordance with NA7.5.7 and NA7.5.9.
Boiler or chillers that require isolation controls as specified by Section 140.4(k)2 or 140.4(k)3 shall be tested in accordance with NA7.5.7.
Hydronic systems with supply water temperature reset controls shall be tested in accordance with NA7.5.8.
Automatic demand shed controls shall be tested in accordance with NA7.5.10.
Fault Detection and Diagnostics (FDD) for Packaged Direct-Expansion Units shall be tested in accordance with NA7.5.11.
Automatic fault detection and diagnostics (FDD) for air handling units and zone terminal units shall be tested in accordance with NA7.5.12.
Distributed Energy Storage DX AC Systems shall be tested in accordance with NA7.5.13.
Thermal Energy Storage (TES) Systems shall be tested in accordance with NA7.5.14.
Supply air temperature reset controls shall be tested in accordance with NA7.5.15.
Water-cooled chillers served by cooling towers with condenser water reset controls shall be tested in accordance with NA7.5.16.
When an energy management control system is installed, it shall functionally meet all of the applicable requirements of Part 6.
Occupant sensing zone controls shall be tested in accordance with NA7.5.17.
Conductivity controls and overflow alarms for open and closed-circuit cooling towers shall be tested according to NA7.5.18.
§ 805.7 High relevance — show source text
(5) A minimum OSA setting is provided where the system is in occupied mode in accordance with this appendix regardless of space carbon dioxide readings.
(6) A maximum OSA damper position for DCV control shall be established in accordance with this appendix, regardless of space carbon dioxide readings.
(7) The outdoor air damper shall modulate open where the carbon dioxide concentration within the space exceeds setpoint.
(8) The outdoor air damper modulates closed (toward minimum position) where the carbon dioxide concentration within the space is below setpoint.
E 805.7 Supply Fan Variable Flow Controls (Form MECH-7A). The purpose of this test is to ensure that the supply fan in a variable air volume application modulates to meet system airflow demand. In most applications, the individual VAV boxes serving each space will modulate the amount of
2025 CALIFORNIA MECHANICAL CODE 485
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
APPENDIX E
air delivered to the space based on heating and cooling requirements. As a result, the total supply airflow provided by the central air handling unit shall vary to maintain sufficient airflow through each VAV box. Airflow shall be controlled using a variable frequency drive (VFD) to modulate supply fan speed and vary system airflow. The most common strategy for controlling the VFD is to measure and maintain static pressure within the duct.
E 805.7.1 Test Procedure. The procedure for performing a functional test for supply fan variable controls shall be in accordance with Section E 805.7.1.1 and Sec tion E 805.7.1.2.
E 805.7.1.1 Construction Inspection. Prior to functional testing, verify and document the following:
(1) Supply fan controls modulate to increase capacity.
(2) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating set point.
(3) Supply fan controls stabilize within a 5 minute period.
E 805.7.1.2 Functional Testing. The functional testing shall be in accordance with the following steps:
Step 1: Simulate demand for design airflow. Verify and document the following:
(1) Supply fan controls modulate to increase capacity.
(2) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating set point. (3) Supply fan controls stabilize within a 5 minute period. Step 2: Simulate demand for minimum airflow. Verify and document the following: (1) Supply fan controls modulate to decrease capacity. (2) Current operating setpoint has decreased (for systems with DDC to the zone level). (3) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating setpoint. (4) Supply fan controls stabilize within a 5 minute period. Step 3: Restore system to correct operating conditions.
E 805.7.2 Acceptance Criteria. Supply fan variable flow controls acceptance criteria shall be as follows: (1) Static pressure sensor(s) is factory calibrated (with calibration certificate) or field calibrated. (2) For systems without DDC controls to the zone level, the pressure sensor setpoint is less than one-third of the supply fan design static pressure.
§ 160.3 High relevance — show source text
(d) Mechanical acceptance testing.
- Common areas. Before an occupancy permit is granted, the following systems and equipment serving multifamily common areas shall be certified as meeting the Acceptance Requirements for Code Compliance, as specified by Reference Nonresidential Appendix NA7. These systems and equipment shall also comply with the applicable requirements of Section
220 2025 CALIFORNIA ENERGY CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
MULTIFAMILY BUILDINGS—MANDATORY REQUIREMENTS
160.3(d)3. A Certificate of Acceptance shall be submitted to the enforcement agency that certifies that the equipment and systems meet the acceptance requirements: A. Outdoor air ventilation systems shall be tested in accordance with NA7.5.1. B. Constant volume, single zone air conditioning and heat pump unit controls shall be tested in accordance with NA7.5.2. C. Duct systems shall be tested in accordance with NA7.5.3 where either: a. They are new duct systems; or b. They are part of an altered system. D. Air economizers, DOAS, HRV or ERV systems shall be tested in accordance with NA7.5.4. Exception to Section 160.3(d)1D: Air economizers installed by the HVAC system manufacturer and certified to the Commission as being factory calibrated and tested are not required to comply with the Functional Testing section of the Air Economizer Controls acceptance test as described in NA7.5.4.2. E. Demand control ventilation systems required by Section 160.2(c)3 shall be tested in accordance with NA7.5.5. F. Supply fan variable flow controls shall be tested in accordance with NA7.5.6. G. Hydronic system variable flow controls shall be tested in accordance with NA7.5.7 and NA7.5.9. H. Boilers or chillers that require isolation controls as specified by Section 170.2(c)4Iii or 170.2(c)4Iiii shall be tested in accordance with NA7.5.7.
I. Hydronic systems with supply water temperature reset controls shall be tested in accordance with NA7.5.8.
J. Automatic demand shed controls shall be tested in accordance with NA7.5.10.
K. Fault detection and diagnostics (FDD) for packaged direct expansion units shall be tested in accordance with NA7.5.11. L. Automatic fault detection and diagnostics (FDD) for air handling units and zone terminal units shall be tested in accordance with NA7.5.12.
M. Distributed energy storage DX AC systems shall be tested in accordance with NA7.5.13. N. Thermal energy storage (TES) systems shall be tested in accordance with NA7.5.14. O. Supply air temperature reset controls shall be tested in accordance with NA7.5.15. P. Water-cooled chillers served by cooling towers with condenser water reset controls shall be tested in accordance with NA7.5.16.
Q. When an energy management control system is installed, it shall functionally meet all of the applicable requirements of Part 6.
§ 803.2.1.3 High relevance — show source text
The responsible person shall perform the field testing and verification work, and where this is the case, the responsible person shall complete and sign both the field technician’s signature block and the responsible person’s signature block on the certificate of acceptance form. The responsible person assumes responsibility for the acceptance testing work performed by the field technician agent or employee. E 803.2.1.3 Certificate of Acceptance. The certificate of acceptance shall be submitted to the Authority Having Jurisdiction in order to receive the final certificate of occupancy. The Authority Having Jurisdiction shall not release a final certificate of occupancy unless the submitted certificate of acceptance demonstrates that the specified systems and equipment have been shown to be performing in accordance with the applicable acceptance requirements. The Authority Having Jurisdiction has the authority to require the field technician and responsible person to demonstrate competence, to its satisfaction. Certificate of acceptance forms are located in Section E 806.0.
E 804.0 Commissioning Tests. E 804.1 General. Functional tests shall be performed on new equipment and systems installed in either new construction or retrofit applications in accordance with this section. The appropriate certificate of acceptance form along with each specific test shall be completed and submitted to the Authority Having Jurisdiction before a final occupancy permit can be granted.
E 804.2 Tests. Functional testing shall be performed on the devices and systems listed in this section. The functional test results are documented using the applicable certificate of acceptance forms shown in parenthesis and located in Section E 806.0. The functional tests shall be performed in accordance with Section E 805.0 using the following forms:
(1) Minimum ventilation controls for constant and variable air volume systems (Form MECH-2A).
(2) Zone temperature and scheduling controls for constant volume, single-zone, unitary air conditioner and heat pump systems (Form MECH-3A).
(3) Duct leakage on a subset of small single-zone systems depending on the ductwork location (Form MECH-4A).
(4) Air economizer controls for economizers that are not factory installed and tested (Form MECH-5A).
(5) Demand-controlled ventilation control systems (Form MECH-6A).
(6) Supply fan variable flow controls (Form MECH-7A).
(7) Valve leakage for hydronic variable flow systems and isolation valves on chillers and boilers in plants with more than one chiller or boiler being served by the same primary pumps through a common header (Form MECH8A).
(8) Supply water temperature reset control strategies programmed into the building automation system for water systems (e.g., chilled, hot, or condenser water) (Form MECH-9A).
(9) Hydronic variable flow controls on a water system where the pumps are controlled by variable frequency drives (e.g., chilled and hot water systems; water-loop heat pump systems) (Form MECH-10A).
(10)Automatic demand shed control (Form MECH-11A).
(11)Fault detection and diagnostic for DX units (Form MECH-12A).
(12)Automatic fault detection and diagnostic systems (AFDD) (Form MECH-13A).
(13)Distributed energy storage DEC/DX AC systems (Form MECH-14A).
(14)Thermal energy storage (TES) systems (Form MECH15A). E 804.3 Acceptance Process. The functional testing process shall comply with Section E 804.3.1 through Section E 804.3.4.
§ 805.6.2 High relevance — show source text
Step 2: Simulate a signal at or slightly above the carbon dioxide concentration setpoint required by this appendix. Verify and document the following:
(1) For single zone units, outdoor air damper modulates open to satisfy the total ventilation air called for in the certificate of compliance.
(2) For multiple zone units, either outdoor air damper or zone damper modulate open to satisfy the zone ventilation requirements.
Step 3: Simulate signal well below the carbon dioxide setpoint. Verify and document the following:
(1) For single zone units, outdoor air damper modulates to the design minimum value.
(2) For multiple zone units, either outdoor air damper or zone damper modulate to satisfy the reduced zone ventilation requirements.
Step 4: Restore economizer controls and remove system overrides initiated during the test.
Step 5: With controls restored, apply carbon dioxide calibration gas at a concentration slightly above the setpoint to the sensor. Verify that the outdoor air damper modulates open to satisfy the total ventilation air called for in the certificate of compliance.
E 805.6.2 Acceptance Criteria. Demand-controlled ventilation systems acceptance criteria shall be as follows:
(1) Each carbon dioxide sensor is factory calibrated (with calibration certificate) or field calibrated.
(2) Each carbon dioxide sensor is wired correctly to the controls to ensure proper control of the outdoor air damper.
(3) Each carbon dioxide sensor is located correctly within the space 1 foot (305 mm) to 6 feet (1829 mm) above the floor.
(4) Interior carbon dioxide concentration setpoint is not more than 600 parts per million (ppm) plus outdoor air carbon dioxide value where dynamically measured or not more than 1000 ppm where no OSA sensor is provided.
(5) A minimum OSA setting is provided where the system is in occupied mode in accordance with this appendix regardless of space carbon dioxide readings.
(6) A maximum OSA damper position for DCV control shall be established in accordance with this appendix, regardless of space carbon dioxide readings.
(7) The outdoor air damper shall modulate open where the carbon dioxide concentration within the space exceeds setpoint.
(8) The outdoor air damper modulates closed (toward minimum position) where the carbon dioxide concentration within the space is below setpoint.
E 805.7 Supply Fan Variable Flow Controls (Form MECH-7A). The purpose of this test is to ensure that the supply fan in a variable air volume application modulates to meet system airflow demand. In most applications, the individual VAV boxes serving each space will modulate the amount of
2025 CALIFORNIA MECHANICAL CODE 485
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
APPENDIX E
air delivered to the space based on heating and cooling requirements. As a result, the total supply airflow provided by the central air handling unit shall vary to maintain sufficient airflow through each VAV box. Airflow shall be controlled using a variable frequency drive (VFD) to modulate supply fan speed and vary system airflow. The most common strategy for controlling the VFD is to measure and maintain static pressure within the duct.
E 805.7.1 Test Procedure. The procedure for performing a functional test for supply fan variable controls shall be in accordance with Section E 805.7.1.1 and Sec tion E 805.7.1.2.
§ 805.8 High relevance — show source text
At full flow:
(1) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating control static pressure setpoint. (2) Supply fan controls stabilizes within a 5 minute period. (3) At minimum flow (not less than 30 percent of total design flow). (4) Supply fan controls modulate to decrease capacity. (5) Current operating setpoint has decreased (for systems with DDC to the zone level). (6) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating setpoint. E 805.8 Valve Leakage (Form MECH-8A). The purpose of this test is to ensure that control valves serving variable flow systems are designed to withstand the pump pressure over the full range of operation. Valves with insufficient actuators will lift under certain conditions causing water to leak through and loss of control. This test applies to the variable flow systems, chilled and hot-water variable flow systems, chiller isolation valves, boiler isolation valves, and watercooled air conditioner and hydronic heat pump systems.
E 805.8.1 Test Procedure. The procedure for performing a functional test for valve leakage shall be in accordance with Section E 805.8.1.1 and Section E
805.8.1.2.
E 805.8.1.1 Construction Inspection. Prior to functional testing, verify and document the valve and piping arrangements were installed in accordance with the design drawings. E 805.8.1.2 Functional Testing. The functional testing shall be in accordance with the following steps:
Step 1: For each pump serving the distribution system, dead head the pumps using the discharge isolation valves at the pumps. Document the following:
(1) Record the differential pressure across the
pumps.
(2) Verify that this is within 5 percent of the submittal data for the pump.
Step 2: Reopen the pump discharge isolation valves. Automatically close valves on the systems being tested. Where three-way valves are present, close off the bypass line. Verify and document the following:
(1) The valves automatically close.
(2) Record the pressure differential across the
pump.
(3) Verify that the pressure differential is within 5 percent of the reading from Step 1 for the pump that is operating during the valve test.
486 2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
APPENDIX E
Step 3: Restore system to correct operating conditions.
E 805.8.2 Acceptance Criteria. System has no flow where coils are closed and the pump is turned on. E 805.9 Supply Water Temperature Reset Controls (Form MECH-9A). The purpose of this test is to ensure that both the chilled water and hot water supply temperatures are automatically reset based on either building loads or outdoor air temperature, as indicated in the control sequences. Many HVAC systems are served by central chilled and heating hot water plants. The supply water operating temperatures shall meet peak loads where the system is operating at design conditions. As the loads vary, the supply water temperatures shall be permitted to be adjusted to satisfy the new operating conditions. The chilled water supply temperature shall be permitted to be raised as the cooling load decreases, and heating hot water supply temperature shall be permitted to be lowered as the heating load decreases.
§ 5.3 High relevance — show source text
(g) Duct sealing. Duct systems shall comply with Subsection 1 or 2 below:
- New duct systems that meet the criteria in Subsections A, B, C and D below shall be sealed to a leakage rate not to exceed 6 percent of the nominal air handler airflow rate as confirmed through acceptance testing, in accordance with Reference Nonresidential Appendix NA7.5.3; A. The duct system does not serve a healthcare facility; and B. The duct system provides conditioned air to an occupiable space for a constant volume, single zone, space-conditioning system; and C. The space-conditioning system serves less than 5,000 square feet of conditioned floor area; and D. The combined surface area of the ducts located outdoors or in unconditioned space is more than 25 percent of the total surface area of the entire duct system.
- New duct systems that are not subject to testing under Section 120.4(g)1 shall instead meet the duct leakage testing requirements of CMC Section 603.9.2.
Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code. Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.8, and 25943, Public Resources Code.
SECTION 120.5—REQUIRED NONRESIDENTIAL MECHANICAL SYSTEM ACCEPTANCE
Nonresidential and hotel/motel buildings shall comply with the applicable requirements of Sections 120.5(a) through 120.5(b).
Exception to Section 120.5: Systems serving healthcare facilities.
(a) Before an occupancy permit is granted, the following equipment and systems shall be certified as meeting the Acceptance Requirements for Code Compliance, as specified by the Reference Nonresidential Appendix NA7. A Certificate of Acceptance shall be submitted to the enforcement agency that certifies that the equipment and systems meet the acceptance requirements:
Outdoor air ventilation systems shall be tested in accordance with NA7.5.1.
Constant volume, single zone unitary air conditioning and heat pump unit controls shall be tested in accordance with NA7.5.2.
Duct systems that are subject to testing under Section 120.4(g)1, Section 141.0(b)2Di or Section 141.0(b)2Dii shall be tested in accordance with NA7.5.3.
Air economizers, DOAS, HRV or ERV systems shall be tested in accordance with NA7.5.4. Exception 1 to Section 120.5(a)4: Air economizers installed by the HVAC system manufacturer and certified to the Commission as being factory calibrated and tested are not required to comply with the Functional Testing section of the air economizer controls acceptance test as described in NA7.5.4.2. Exception 2 to Section 120.5(a)4: The DOAS, HRV, or ERV unit that does not meet the exhaust air heat recovery ratio as specified in Section 140.4(q)1 or does not include bypass or control to disable energy recovery as specified in Section 140.4(q)2.
Demand control ventilation systems required by Section 120.1(c)3 shall be tested in accordance with NA7.5.5.
Supply fan variable flow controls shall be tested in accordance with NA7.5.6.
§ 110.5 High relevance — show source text
7(b) Spa Heater 110.5(d) Space Conditioning 110.8(d)3, 120.6(f), 170.1(d), 170.2(c), 170.2(c)4 Distribution 150.1(c), 170.2(c)3 Equipment 110.2 System 120.1(f), 120.2(k), 120.3(a), 120.4(g), 140.1(a), 140.4, 140.4(c)3, 140.4(e)2, 141.0(a)1, 141.0(a)2, 141.0(b)2, 141.0(b)2C, 141.0(b)2D, 141.0(b)2E, 141.0(b)3, 150.0(h), 150.0(m)11, 150.0(m)12, 150.0(m)13, 150.1(b)3, 150.2(b)1C, D, E, F, 160.2(b)1, 160.3, 160.3(b), 160.3(b)6, 180.2(b)2
2025 CALIFORNIA ENERGY CODE 319
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
INDEX
140.4(o), 140.4(p), 141.1(b), 150.0(m)1, 150.0(m)12, 160.3(b)5A-F, 160.3(c)2, 170.2(c)4M Air sensor 140.4(e)2 Air temperature 140.4(d), 140.4(f), 140.9(a), 140.9(c) Air temperature reset controls 120.5(a)15, 160.3(d), 170.2(c)4D Collocated 150.0(s) Fan Power Allowances (watts/cfm) Table 140.4-A, Table 170.2-B Fan variable flow controls 10-103(b), 10-103(c), 120.5(a)6, 160.3(d) Flow 140.4(o), 140.9(b), 170.2(c)4M Plenum 150.0(m), 160.3(b)G-L Supply-only fan 140.4(c)1 Supply-only ventilation 160.2(b)1, 160.2(c)1 Temperature 140.4(k)7, 170.2(c) Water temperature reset controls 120.5(a)9, 160.3(d) Suspended Ceiling 120.7(a)3 Switched Outlets 150.0(k)2, 160.5(a)2 Switches 110.4(b), 110.9(b)6, 130.1(c), 130.5(d), 150.0(p), 160.2(b), 160.5(b), 160.6(d) System Capacity Table 140.4(e), 140.9(c)3, 140.10(b), 150.1(c)8, 150.2(a), Table 170.2-E, 170.2(h), 180.1 Design 10-103, 150.0(m)12, 160.2(a), 160.2(b) Efficacy 130.1(c)7 Efficiency 120.6(a)8, 120.
§ 503.7.1 High relevance — show source text
2025 CALIFORNIA MECHANICAL CODE 441
«
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
APPENDIX E
Exception: Heat-rejection devices whose energy use is included in the equipment efficiency ratings listed in Table E 503.7.1(1) through Table E 503.7.1(4).
[ASHRAE 90.1:6.5.5.1]
E 503.5.8.1 Fan Speed Control. The fan system on a heat-rejection device powered by an individual motor or an array of motors with a connected power, including the motor service factor, totaling 5 hp (3.7 kW) or more shall have controls and/or devices (such as variable-speed control) that shall result in fan motor demand of no more than 30 percent of design wattage at 50 percent of the design airflow and that shall automatically modulate the fan speed to control the leaving fluid temperature or condensing temperature/pressure of the heat-rejection device.
Exceptions:
(1) Condenser fans serving multiple refrigerant or fluid cooling circuits.
(2) Condenser fans serving flooded condensers.
[ASHRAE 90.1:6.5.5.2.1]
E 503.5.8.2 Variable-Speed Fan Drives. Multicell heat rejection equipment with variable-speed fan drives shall:
(1) Operate the maximum number of fans allowed that comply with the manufacturer’s requirements for all system components.
(2) Control all fans to the same fan speed required for the instantaneous cooling duty, as opposed to staged (on/off) operation. Minimum fan speed shall comply with the minimum allowable speed of the fan drive system per the manufacturer’s recommendations. [ASHRAE 90.1:6.5.5.2.2]
E 503.5.9 Limitation on Centrifugal Fan Open- Circuit Cooling Towers. Centrifugal fan open-circuit cooling towers with a combined rated capacity of 1100 gallons per minute (gpm) (69.39 L/s) or greater at 95°F (35°C) condenser water return, 85°F (29°C) condenser water supply, and 75°F (24°C) outdoor air wet-bulb tem
perature shall comply with the energy efficiency requirement for axial fan open-circuit cooling towers in accordance with Table E 503.7.1(7).
Exception: Centrifugal open-circuit cooling towers that are ducted (inlet or discharge) or require external sound attenuation. [ASHRAE 90.1:6.5.5.3]
E 503.5.9.1 Tower Flow Turndown. Open-circuit cooling towers used on water-cooled chiller systems that are configured with multiple- or variable-speed condenser water pumps shall be designed so that all open-circuit cooling tower cells can be run in parallel with the larger of the following:
(1) The flow that is produced by the smallest pump at its minimum expected flow rate. (2) Fifty percent of the design flow for the cell.
[ASHRAE 90.1:6.5.5.4] E 503.5.10 Energy Recovery. Energy recovery shall be in accordance with Section E 503.5.10.1. through Section E 503.5.10.4.
§ 805.7.1.1 High relevance — show source text
E 805.7.1.1 Construction Inspection. Prior to functional testing, verify and document the following:
(1) Supply fan controls modulate to increase capacity.
(2) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating set point.
(3) Supply fan controls stabilize within a 5 minute period.
E 805.7.1.2 Functional Testing. The functional testing shall be in accordance with the following steps:
Step 1: Simulate demand for design airflow. Verify and document the following:
(1) Supply fan controls modulate to increase capacity.
(2) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating set point. (3) Supply fan controls stabilize within a 5 minute period. Step 2: Simulate demand for minimum airflow. Verify and document the following: (1) Supply fan controls modulate to decrease capacity. (2) Current operating setpoint has decreased (for systems with DDC to the zone level). (3) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating setpoint. (4) Supply fan controls stabilize within a 5 minute period. Step 3: Restore system to correct operating conditions.
E 805.7.2 Acceptance Criteria. Supply fan variable flow controls acceptance criteria shall be as follows: (1) Static pressure sensor(s) is factory calibrated (with calibration certificate) or field calibrated. (2) For systems without DDC controls to the zone level, the pressure sensor setpoint is less than one-third of the supply fan design static pressure.
(3) For systems with DDC controls with VAV boxes reporting to the central control panel, the pressure setpoint is reset by zone demand (box damper position or a trim and respond algorithm).
At full flow:
(1) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating control static pressure setpoint. (2) Supply fan controls stabilizes within a 5 minute period. (3) At minimum flow (not less than 30 percent of total design flow). (4) Supply fan controls modulate to decrease capacity. (5) Current operating setpoint has decreased (for systems with DDC to the zone level). (6) Supply fan maintains discharge static pressure within plus or minus 10 percent of the current operating setpoint. E 805.8 Valve Leakage (Form MECH-8A). The purpose of this test is to ensure that control valves serving variable flow systems are designed to withstand the pump pressure over the full range of operation. Valves with insufficient actuators will lift under certain conditions causing water to leak through and loss of control. This test applies to the variable flow systems, chilled and hot-water variable flow systems, chiller isolation valves, boiler isolation valves, and watercooled air conditioner and hydronic heat pump systems.
E 805.8.1 Test Procedure. The procedure for performing a functional test for valve leakage shall be in accordance with Section E 805.8.1.1 and Section E
805.8.1.2.
E 805.8.1.1 Construction Inspection. Prior to functional testing, verify and document the valve and piping arrangements were installed in accordance with the design drawings. E 805.8.1.2 Functional Testing. The functional testing shall be in accordance with the following steps:
§ 0.004 High relevance — show source text
35|0.004|–|–| |0.71
|0.013
|0.003
|–
| |1.06
|0.025
|0.005
|–
| |1.41
|0.041
|0.008
|–
| |1.77
|0.060
|0.012
|–
| |2.12
|0.082
|0.016
|–
| |2.47
|0.107
|0.021
|–
| |2.82
|0.135
|0.026
|–
| |3.18|0.166|0.032|–| |3.53|0.199|0.038|–| |4.24|0.274|0.053|–| |4.94|0.359|0.069|–| |5.65|0.454|0.087|–| |6.36|0.558|0.107|–| |7.06|0.672|0.129|0.033| |7.77|0.795|0.153|0.039| |8.47|0.927|0.179|0.045| |9.18|1.066|0.205|0.052| |9.89|1.218|0.233|0.059| |10.59|1.377|0.263|0.066| |12.36|1.811|0.346|0.087| |14.12|2.298|0.438|0.110| |15.89|2.837|0.539|0.135| |17.66|3.456|0.650|0.163| |19.42|–|0.771|0.193| |21.19|–|0.900|0.225| |22.95|–|1.038|0.260| |24.72|–|1.185|0.295| |28.25|–|1.505|0.375| |31.78|–|1.859|0.463| |35.31|–|2.247|0.559| |38.84|–|2.667|0.663| |42.37|–|3.121|0.775| |45.90|–|3.607|0.895| |49.43|–|4.125|1.022| |52.97|–|–|1.157| |56.50|–|–|1.299| |60.03|–|–|1.449| |63.56|–|–|1.607| |67.09|–|–|1.772| |70.62|–|–|1.944| |81.21|–|–|2.503| |91.81|–|–|3.127| |102.40|–|–|3.813|For SI units: 1 standard cubic foot per minute = 28.32 SLPM, 1 inch = 25 mm, 1 foot = 304.8 mm, 1 pound-force per square inch = 6.8947 kPa
Frequently asked questions
Who must perform the supply‑fan variable‑flow acceptance test?
When Title 24 Part 1 requires certification, the acceptance testing specified by § 120.5 must be performed by a Certified Mechanical Acceptance Test Technician (CMATT) (or under a CMATT‑certified employer) as described in Part 1.
What documentation is required after testing?
A completed Certificate of Acceptance (MECH‑7A for supply fan VFD / E 805.7 checklist) showing the functional test results and sensor calibration must be submitted to the enforcement agency before final occupancy.
What tolerance is allowed for static pressure control during the test?
The supply fan must maintain discharge static pressure within ±10% of the current operating setpoint during both design and minimum flow simulations.
If the system has DDC reporting from VAV boxes, does the pressure setpoint requirement change?
Yes. For systems with DDC and VAV boxes reporting to the central control, the pressure setpoint must be reset by zone demand (box damper position or a trim & respond algorithm) rather than using the one‑third‑of‑design rule that applies to non‑DDC systems.
Is there a minimum turndown the fan must demonstrate?
The test requires demonstration at minimum flow not less than 30% of total design flow (i.e., the system must operate and be tested down to at least 30% of design).
More in California Energy Code
- Compliance paths, energy budgets, performance modeling and forms/software requirements
- Controls, commissioning, demand-response, sensors, and field verification/diagnostic testing
- Domestic hot water systems, efficiency, controls and installation requirements
- Electrical infrastructure, EV charging readiness, load management and demand controls
- Envelope construction, insulation, fenestration and thermal performance
- HVAC systems, ventilation rates, ducting, controls and testing
- Interior and exterior lighting power, controls and daylighting requirements
- Mandatory measures, appliance efficiency and certification requirements
- Photovoltaic requirements, BESS (battery energy storage) sizing and SARA procedures
- Reference appendices, test procedures, product certification and labeling requirements
- Scope, applicability, definitions and administrative requirements
Ask about the California Energy Code
Get cited, plain-English answers on the California Energy Code for your project — any code section, any scenario.
Start Free Trial