CMC · California Mechanical Code
How to size, mount and install circulators and pumps
The CMC requires pumps to be chosen for the actual heat‑transfer fluid, system temperature and pressure, installed to permit service and per manufacturer instructions, and motors ≤600V must meet CSA or UL listings (see § 1208.1). I could not retrieve the detailed text of § 1208.2 (Mounting) or § 1208.3 (Sizing) from the provided file previews — tell me if you want me to fetch those subsections so I can add any numeric clearances or sizing rules from the CMC itself.
Last reviewed: July 6, 2026
What the code requires — 2–4 sentences
Circulators and pumps must be selected for their intended use — taking into account the heat transfer fluid, intended operating temperature range and system pressure — and installed so they can be serviced and maintained. Follow the manufacturer’s installation instructions for orientation and installation. In addition, motor‑operated pumps rated 600V or less must comply with CSA C22.2 No. 108 or UL 778. See § 1208.1 for these requirements.
Pick a pump that is rated for the fluid, temperature and pressure you will actually run it at, mount it so technicians can get to it, and follow the manufacturer’s instructions and the electrical standards. (Most of this is stated in § 1208.1.)
Requirements in detail
A — Selection (what the code explicitly requires)
Select circulators/pumps for their intended use, based on:
- Heat transfer fluid (type and any additives),
- Intended operating temperature range, and
- Intended operating pressure.
These are mandatory selection criteria per § 1208.1.
For motor‑operated pumps rated 600V or less, the pump motor must comply with CSA C22.2 No. 108 or UL 778 (electrical safety/standard listing). 600V is the key threshold called out in § 1208.1.
Install so the pump allows for service and maintenance; follow the manufacturer’s installation instructions for correct orientation and installation. Those service/access and manufacturer instruction requirements are in § 1208.1.
Note: The code headings for § 1208.2 (Mounting) and § 1208.3 (Sizing) appear in the chapter index, but the detailed text for those specific subsections was not available in the retrieved files. Where I cite § 1208.2 or § 1208.3 below I will explicitly indicate if the source text was not retrieved.
B — Mounting and access (what the code says and what we can infer)
The explicit, retrievable requirement is: pumps must be installed to allow for service and maintenance, and orientation must follow the manufacturer’s instructions (both in § 1208.1). This obligates installers to plan clearances, isolation valves, electrical disconnects and piping geometry to permit removal or servicing of the unit.
The specific detailed mounting rules under § 1208.2 (for example, minimum clearances, base anchorage, vibration isolation specifics) could not be located in the retrieved preview; therefore I cannot assert any additional mandatory numeric clearances or mounting geometry from the CMC text for § 1208.2 here. If you want those exact requirements I can retrieve the full text of § 1208.2 on request.
C — Sizing (what the code provides / what is missing)
The code states a sizing subsection exists as § 1208.3 (index), but the detailed sizing text was not present in the retrieved snippet. Because the CMC text for § 1208.3 was not available in the search preview, I cannot quote or restate any mandatory sizing formulas, minimum flows, head requirements, or sizing tables from the CMC itself. To comply strictly with the CMC you should consult § 1208.3 directly (or I can retrieve it).
Practical note (non‑code guidance — do not substitute for § 1208.3): typical good practice is to size pumps to deliver the system design flow at the system design head with some margin for throttling and future changes, but the CMC’s required method (if any) in § 1208.3 must be checked in the full text. (I did not retrieve that detailed sizing language.)
Decision‑relevant table
| Decision item | Typical values / actions | Code Reference |
|---|---|---|
| Select for heat transfer fluid | Use pump rated for the fluid (water, glycol mix, heat transfer oil, etc.) | § 1208.1 |
| Select for operating temperature range | Pump and seal ratings must equal or exceed system temperatures | § 1208.1 |
| Select for operating pressure | Pump pressure class compatible with system pressure | § 1208.1 |
| Orientation & manufacturer instructions | Follow manufacturer’s installation instructions for correct orientation | § 1208.1 |
| Service access | Install to allow service/maintenance (access, valves, electrical disconnect) | § 1208.1 |
| Motor electrical standard | Motors ≤ 600V: comply with CSA C22.2 No. 108 or UL 778 | § 1208.1 |
| Mounting numeric clearances / sizing rules | Not present in retrieved preview — consult § 1208.2 and § 1208.3 (text not retrieved) | § 1208.2, § 1208.3 (text not retrieved) |
Exceptions & special cases
- The retrievable CMC language for this topic is limited to the general selection/installation and motor listing requirements in § 1208.1. Any code exceptions or special-case text contained in § 1208.2 or § 1208.3 could not be confirmed from the retrieved files. Because I cannot find those subsection texts in the preview, I cannot authoritatively list exceptions that might be present there. If you need those specific exceptions or variances, I can fetch the full text of § 1208.2 and § 1208.3 and update this article.
Common mistakes
- Installing a pump that is not rated for the actual heat transfer fluid (e.g., using seals/materials for plain water when glycol or corrosion inhibitors are in the loop). This violates the compatibility requirement in § 1208.1.
- Blocking access: mounting pumps where the motor, coupling or flange bolts cannot be reached for service (contrary to the service/maintenance access requirement in § 1208.1).
- Ignoring manufacturer orientation instructions (many wet‑rotor circulators require shaft horizontal or vertical orientation per the manufacturer — the CMC requires following those instructions, per § 1208.1).
- Using an unlisted motor: installing a motor ≤ 600V that is not listed to CSA C22.2 No. 108 or UL 778. § 1208.1 mandates those standards for motor‑operated pumps rated 600V or less.
- Assuming numeric mounting clearances or sizing formulas from practice guides when the actual CMC subsections § 1208.2 and § 1208.3 (which may contain such details) have not been confirmed — the text for those subsections was not retrieved here, so verify before plan submittal.
Worked example — applying the retrievable code text
Scenario: small hydronic space‑heating loop with a glycol/water mix, served by a motor‑driven circulator.
Selection per code:
- Confirm the pump and seals are compatible with glycol/water (pump materials and mechanical seal rated for glycol). This is required by § 1208.1.
- Confirm pump temperature rating exceeds the expected operating temperature (say design temperature 180°F / 82°C). This follows § 1208.1’s requirement to select for intended operating temperature range.
Electrical compliance:
- If the circulator uses a single‑phase 120V or 240V motor (i.e., ≤ 600V), verify the motor is listed to CSA C22.2 No. 108 or UL 778 and keep the label for inspection. This meets § 1208.1.
Mounting and service access:
- Install the pump so an operator or technician can remove the motor/coupling and access flange bolts; provide isolation valves and a serviceable electrical disconnect in reach (this is a direct application of the installer’s obligation under § 1208.1 to allow service/maintenance and follow manufacturer instructions).
Sizing (what I can and cannot do from the retrieved code):
- The CMC index shows there is a § 1208.3 Sizing subsection, but the detailed sizing text was not in the retrieved preview. Therefore I cannot complete a code‑based numerical pump sizing calculation from the CMC text here; you must consult § 1208.3 or provide its text.
Related provisions
- § 1208.1 — General circulator and pump selection/installation requirements (retrieved).
- § 1208.2 — Mounting (heading present in index; full text not retrieved).
- § 1208.3 — Sizing (heading present in index; full text not retrieved).
- § 1205.0 — Installation, testing and inspection (general installation requirements referenced from chapter).
- § 1210.1 / Table 1210.1 — Materials for hydronic system piping, tubing and fittings (material compatibility and referenced standards).
- § 1210.3 — Hangers and supports (equipment support requirements referenced by hydronics chapter).
- § 1209.0 — Expansion tanks (related hydronic equipment).
- Chapter 12 index (shows circulators and hydronics topics and where to look for clearance/mounting elsewhere in the chapter).
If you want, I can fetch and quote the full text of § 1208.2 and § 1208.3 so this article can include the CMC’s explicit numeric mounting clearances, vibration isolation requirements, piping arrangement requirements, and any mandatory sizing formulas or tables contained in those subsections. I did not find those subsection texts in the retrieved preview and therefore did not invent or assume their contents.
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
California Mechanical Code High relevance — show source text
LEADER,
OR PIPE|FLOW|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)**| |inches|gpm1|1 (in/h)|2 (in/h)|3 (in/h)|4 (in/h)|5 (in/h)|6 (in/h)|7 (in/h)|8 (in/h)|9 (in/h)|10 (in/h)|11 (in/h)|12 (in/h)| |2|30|2880|1440|960|720|575|480|410|360|320|290|260|240| |3|92|8800|4400|2930|2200|1760|1470|1260|1100|980|880|800|730| |4|192|18 400|9200|6130|4600|3680|3070|2630|2300|2045|1840|1675|1530| |5|360|34 600|17 300|11 530|8650|6920|5765|4945|4325|3845|3460|3145|2880| |6|563|54 000|27 000|17 995|13 500|10 800|9000|7715|6750|6000|5400|4910|4500| |8|1208|116 000|58 000|38 660|29 000|23 200|19 315|16 570|14 500|12 890|11 600|10 545|9600|CMC § 1206.2 High relevance — show source text
1206.2 Discharge Piping . . . . . . . . . . . . . 259
1207.0 Heating Appliances and Equipment . . . . . . . . . . . . . . . . . . 259
1207.1 General. . . . . . . . . . . . . . . . . . . . . 259
1207.2 Boilers. . . . . . . . . . . . . . . . . . . . . . 259
1207.3 Dual Purpose Water Heaters . . . . 259
1207.4 Solar Heat Collector Systems. . . . 259
1207.5 Heat Pumps . . . . . . . . . . . . . . . . . 259
1208.0 Circulators and Pumps . . . . . . . . . 259
1208.1 General. . . . . . . . . . . . . . . . . . . . . 259
1208.2 Mounting. . . . . . . . . . . . . . . . . . . . 260
1208.3 Sizing . . . . . . . . . . . . . . . . . . . . . . 260
1209.0 Expansion Tanks . . . . . . . . . . . . . 260
1209.1 General. . . . . . . . . . . . . . . . . . . . . 260
1209.2 Installation . . . . . . . . . . . . . . . . . . 260
1209.3 Closed-Type Tanks . . . . . . . . . . . 260
1209.4 Sizing . . . . . . . . . . . . . . . . . . . . . . 260
1210.0 Materials . . . . . . . . . . . . . . . . . . . . 260
1210.1 Piping, Tubing, and Fittings . . . . . 260
1210.2 Expansion and Contraction . . . . . . 260
1210.3 Hangers and Supports . . . . . . . . . 260
1210.4 Oxygen Diffusion Corrosion . . . . . 260
1211.0 Joints and Connections . . . . . . . . 260
1211.1 General. . . . . . . . . . . . . . . . . . . . . 260
1211.2 Pipe Bends . . . . . . . . . . . . . . . . . . 260
Table 1210.1 Materials for Hydronic System Piping, Tubing, and Fittings . . . . . 261
Table 1211.2.2 Minimum Bend Radius
for PE Pipe Installed in Open Cut Trench . . . . . . . . . . . . . 262
1211.3 Chlorinated Polyvinyl Chloride (CPVC) Pipe . . . . . . . . . . . . . . . . . 262
1211.4 CPVC/AL/CPVC Plastic Pipe and Joints . . . . . . . . . . . . . . . . . . . 262
2025 CALIFORNIA MECHANICAL CODE
1211.5 Copper or Copper Alloy Pipe and Tubing . . . . . . . . . . . . . . . . . . 262
CMC § 1204.1 High relevance — show source text
1204.1 General. . . . . . . . . . . . . . . . . . . . . 258
1204.2 Color and Information . . . . . . . . . . 258
1204.3 Potable Water. . . . . . . . . . . . . . . . 258
1204.4 Nonpotable Water. . . . . . . . . . . . . 258
2025 CALIFORNIA MECHANICAL CODE
xl
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
TABLE OF CONTENTS
Table 1204.3 Minimum Length of Color Field and Size of Letters. . . . . . . . 258
1204.5 Location of Piping Identification . . . 258
1204.6 Flow Directions . . . . . . . . . . . . . . . 258
1204.7 Heat Transfer Fluid. . . . . . . . . . . . 258
1204.8 Identification of Chemical
Additives . . . . . . . . . . . . . . . . . . . . 258
1205.0 Installation, Testing, and Inspection . . . . . . . . . . . . . . . . . . . 258
1205.1 Operating Instructions . . . . . . . . . 258
1205.2 Pressure Testing . . . . . . . . . . . . . 258
1205.3 Flushing . . . . . . . . . . . . . . . . . . . . 259
1206.0 Pressure and Safety Devices . . . . 259
1206.1 General. . . . . . . . . . . . . . . . . . . . . 259
1206.2 Discharge Piping . . . . . . . . . . . . . 259
1207.0 Heating Appliances and Equipment . . . . . . . . . . . . . . . . . . 259
1207.1 General. . . . . . . . . . . . . . . . . . . . . 259
1207.2 Boilers. . . . . . . . . . . . . . . . . . . . . . 259
1207.3 Dual Purpose Water Heaters . . . . 259
1207.4 Solar Heat Collector Systems. . . . 259
1207.5 Heat Pumps . . . . . . . . . . . . . . . . . 259
1208.0 Circulators and Pumps . . . . . . . . . 259
1208.1 General. . . . . . . . . . . . . . . . . . . . . 259
1208.2 Mounting. . . . . . . . . . . . . . . . . . . . 260
1208.3 Sizing . . . . . . . . . . . . . . . . . . . . . . 260
1209.0 Expansion Tanks . . . . . . . . . . . . . 260
1209.1 General. . . . . . . . . . . . . . . . . . . . . 260
1209.2 Installation . . . . . . . . . . . . . . . . . . 260
1209.3 Closed-Type Tanks . . . . . . . . . . . 260
CMC § 1015.5 Medium relevance — show source text
Screen porches 1015.5 Stairs 1015.2
Vehicle barrier 406.4.2, 1607.11 Windows 1015.8
Gutters 1502.3 Gymnasiums 303.4 Group E 303.1.3 Live load Table 1607.1 Occupant load 1004.5 Gypsum Chapter 25 Board Chapter 25 Ceiling diaphragms 2508.6 Concrete, reinforced gypsum 2514 Construction 2508 Draftstopping 718.3.1 Exterior soffit Table 2506.2 Fastening Table 2306.3(3), 2508.1 Fire resistance 719, 722.2.1.4, 722.6.2 Fire-resistant joint treatment 2508.5 Inspection 2503 Lath 2507, 2510 Lathing and furring for cement plaster 719, 2510 Lathing and plastering 2507 Materials 2506
Panel products Chapter 25 Performance 2502 Plaster, exposed aggregate 2513 Plaster, exterior 2512 Plaster, interior 2511 Shear wall construction Table 2306.3(3), 2308.10.3, 2505 Sheathing Table 2308.9.9, Table 2508.1, 2508.2, 2508.5, 2510.5.2.2 Showers and water closets 2509
Stucco 2510
Veneer base 2507.2
Veneer plaster 2507.2, 2511.1, Table 2511.1.1
Vertical and horizontal assemblies
2504
Wallboard Table 2506.2, 2508.2, 2508.2.1, 2508.4, 2510.5.2.1 Water-resistant backing board 2506.2, 2509.2
Habitable Space 1208 Handrails 1014 Alternating tread devices 1011.14 Assembly aisles 1030.16 Construction 1014.5, 1014.6, 1014.7 Extensions 1014.7 Glazing 2407 Graspability 1014.4 Guards 1015.3 Height 1014.2 Loads 1607.9
Location 1014.1, 1014.8, 1014.9,
1014.10
Ramps 1012.8 Stairs 1011.11
Hardboard 1403.3.2, 2303.1.7 Hardware (see Doors and Locks and Latching) Hardwood
Fastening 2304.10 Quality 2303.3 Veneer 1403.3.2 Hazardous Materials 307, 414, 415 Compliance with California Fire Code 307.2
Control areas 414.2
Explosion control 414.5.1, Table 414.5.1, 415.11.6.5, 426.1.4 Mercantile occupancies 309.2 Reporting 414.1.3 Sprinkler protection Table 414.2.5.1, Table 414.2.5.2, 415.4, 415.11.12,
903.2.5
CMC § 1208.0 Medium relevance — show source text
1208.0 Circulators and Pumps. 1208.1 General. Circulators and pumps shall be selected for their intended use based on the heat transfer fluid, intended operating temperature range and pressure. Circulators and pumps shall be installed to allow for service and maintenance. The manufacturer’s installation instructions shall be followed for correct orientation and installation. Motor operated pumps rated 600V or less shall comply with CSA C22.2 No. 108 or UL 778.
2025 CALIFORNIA MECHANICAL CODE 259
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
HYDRONICS
temperature and pressure of the system and shall be compatible with the type of heat transfer fluid. Pipe fittings and valves shall be approved for the specific installation with the piping, materials to be installed and shall comply with the applicable standards referenced in Table 1210.1. Where required, exterior piping shall be protected against freezing, UV radiation, corrosion and degradation. Embedded pipe or tubing shall comply with Section 1221.2. 1210.2 Expansion and Contraction. Pipe and tubing shall be so installed that it will not be subject to undue strains or stresses, and provisions shall be made for expansion, contraction, and structural settlement. [OSHPD 1, 1R, 2, 4 & 5] Pipe connections less than 2½ inches (64 mm) to heating coils, cool- ing coils, humidifiers, and similar equipment shall have flexible connectors or three (3) 90-degree offsets in close proximity of the connection.
1210.3 Hangers and Supports. Pipe and tubing shall be supported in accordance with Section 313.0. Equipment that is part of the piping system shall be provided with additional support in accordance with this code and manufacturer’s installation instructions. Radiant systems utilizing heat emission or transfer plates shall have a gap of at least ¼ inch (6.4 mm) between adjacent plates. 1210.4 Oxygen Diffusion Corrosion. PEX and PE-RT tubing in closed hydronic systems shall contain an oxygen barrier. 1210.4.1 Vented Closed-Loop Systems. All components installed in a vented closed-loop system shall be constructed of non-ferrous or other corrosion resistant
materials.
1210.4.2 Non-Oxygen Barrier Closed-Loop Sys- tems. All components installed in a non-oxygen barrier system shall be constructed of non-ferrous or other corrosion resistant materials.
1211.0 Joints and Connections.
1211.1 General. Joints and connections shall be of an approved type. Joints shall be gas and watertight and designed for the pressure of the hydronic system. Changes in direction shall be made by the use of fittings or with pipe bends. Joints between pipe and fittings shall be installed in accordance with the manufacturer’s installation instructions. Joints used underground shall be of an approved type for buried applications in accordance with Section 1221.2.3.
1211.2 Pipe Bends. Pipe bends shall be formed in accordance with Section 1211.2.1 for PEX or Section 1211.2.2 for
PE.
CMC § 1201.5. Medium relevance — show source text
The minimum return-water temperature to the heat source shall comply with Section 1201.5.
1207.3 Dual Purpose Water Heaters. Water heaters used for combined space- and water-heating applications shall be in accordance with the standards referenced in Table 1203.2, and shall be installed in accordance with the manufacturer’s instal lation instructions. Water used as the heat transfer fluid in the hydronic heating system shall be isolated from the potable water supply and distribution in accordance with Section 312.1, Section 1202.0, and Section 1218.0.
1207.3.1 Temperature Limitations. Where a combined space- and water-heating application requires water for space heating at temperatures exceeding 140°F (60°C), a thermostatic mixing valve in accordance with ASSE 1017 shall be installed to temper the water supplied to the potable water distribution system to a temperature of 140°F (60°C) or less. 1207.4 Solar Heat Collector Systems. Solar water heating systems used in hydronic panel radiant heating systems shall be installed in accordance with the Uniform Solar, Hydronics and Geothermal Code (USHGC). 1207.5 Heat Pumps. Heat pumps shall comply with UL 1995 or UL 60335-2-40. Air source heat pumps shall also comply with AHRI 210/240. In addition, ground-source heat pumps shall comply with AHRI/ASHRAE/ISO 13256-1 for water-to-air heat pumps and AHRI/ASHRAE/ISO 13256-2 for water-to-water heat pumps. Heat pumps shall be fitted with a means to indicate that the compressor is locked out.
1208.0 Circulators and Pumps. 1208.1 General. Circulators and pumps shall be selected for their intended use based on the heat transfer fluid, intended operating temperature range and pressure. Circulators and pumps shall be installed to allow for service and maintenance. The manufacturer’s installation instructions shall be followed for correct orientation and installation. Motor operated pumps rated 600V or less shall comply with CSA C22.2 No. 108 or UL 778.
2025 CALIFORNIA MECHANICAL CODE 259
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
HYDRONICS
temperature and pressure of the system and shall be compatible with the type of heat transfer fluid. Pipe fittings and valves shall be approved for the specific installation with the piping, materials to be installed and shall comply with the applicable standards referenced in Table 1210.1. Where required, exterior piping shall be protected against freezing, UV radiation, corrosion and degradation. Embedded pipe or tubing shall comply with Section 1221.2. 1210.2 Expansion and Contraction. Pipe and tubing shall be so installed that it will not be subject to undue strains or stresses, and provisions shall be made for expansion, contraction, and structural settlement. [OSHPD 1, 1R, 2, 4 & 5] Pipe connections less than 2½ inches (64 mm) to heating coils, cool- ing coils, humidifiers, and similar equipment shall have flexible connectors or three (3) 90-degree offsets in close proximity of the connection.
CMC § 12-6 Medium relevance — show source text
1203 Temperature Control . . . . . . . . . . . . . . . . . . . . . . . . . . 12-6
1204 Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7
1205 Yards or Courts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-7
1206 Sound Transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-8
1207 Enhanced Classroom Acoustics . . . . . . . . . . . . . . . . . 12-8
1208 Interior Space Dimensions . . . . . . . . . . . . . . . . . . . . . 12-8
1209 Access to Unoccupied Spaces. . . . . . . . . . . . . . . . . . . 12-9
1210 Toilet and Bathroom Requirements . . . . . . . . . . . . . 12-9
1211 UV Germicidal Irradiation Systems . . . . . . . . . . . . . 12-10
1212 [HCD 1 & HCD 2] Garage Door Springs . . . . . . . . . . . .12-10
1213 [HCD 1] Pollutant Control . . . . . . . . . . . . . . . . . . . . . . .12-11
1214 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11
1215 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11
1216 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11
1217 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11
1218 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11
1219 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11
1220 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11
1221 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12-11
CMC § 0.06 Medium relevance — show source text
AT VARIOUS RAINFALL RATES**
(square feet)|MAXIMUM ALLOWABLE HORIZONTAL PROJECTED ROOF AREAS AT VARIOUS RAINFALL RATES
(square feet)| |inches|gpm1|1 (in/h)|2 (in/h)|3 (in/h)|4 (in/h)|5 (in/h)|6 (in/h)|7 (in/h)|8 (in/h)|9 (in/h)|10 (in/h)|11 (in/h)|12 (in/h)| |2|30|2880|1440|960|720|575|480|410|360|320|290|260|240| |3|92|8800|4400|2930|2200|1760|1470|1260|1100|980|880|800|730| |4|192|18 400|9200|6130|4600|3680|3070|2630|2300|2045|1840|1675|1530| |5|360|34 600|17 300|11 530|8650|6920|5765|4945|4325|3845|3460|3145|2880| |6|563|54 000|27 000|17 995|13 500|10 800|9000|7715|6750|6000|5400|4910|4500| |8|1208|116 000|58 000|38 660|29 000|23 200|19 315|16 570|14 500|12 890|11 600|10 545|9600|For SI units: 1 inch = 25 mm, 1 gallon per minute = 0.06 L/s, 1 inch per hour = 25.4 mm/h, 1 square foot = 0.0929 m [2]
Notes: 1 Maximum discharge capacity, gpm (L/s) with approximately 1 3 ⁄ 4 inch (44 mm) head of water at the drain. 2 For rainfall rates other than those listed, determine the allowable roof area by dividing the area given in the 1 inch per hour (25.4 mm/h) column by the desired rainfall rate. 3 Vertical piping shall be round, square, or rectangular. Square pipe shall be sized to enclose its equivalent round pipe. Rectangular pipe shall have not less than the same cross-sectional area as its equivalent round pipe, except that the ratio of its side dimensions shall not exceed 3 to 1.
(3) For two adjacent walls of unequal height – add 35 percent of the total common height and add 50 percent of the remaining height of the highest wall. (4) Two opposite walls of same height – add no additional
area.
CMC § 503.5.6.5 Medium relevance — show source text
covered by Section E 503.5.6.5 and having a fan nameplate electrical input power of less than 180 W or having a motor nameplate horsepower less than
1 / 12 hp (62.1 W) shall meet the fan efficacy requirements specified in ASHRAE 90.1. [ASHRAE 90.1:6.5.3.7]
E 503.5.6.7 Ventilation Design. The required minimum outdoor air rate is the larger of the minimum outdoor air rate or the minimum exhaust air rate
required by Chapter 4, ASHRAE 62.1, ASHRAE 62.2, ASHRAE/ASHE 170, or applicable codes or accreditation standards. Outdoor air ventilation systems shall comply with one of the following:
(1) Design minimum system outdoor air provided shall not exceed 135 percent of the required minimum outdoor air rate.
(2) Dampers, ductwork, and controls shall be provided that allow the system to supply no more than the required minimum outdoor air rate with a single setpoint adjustment.
(3) The system includes exhaust air energy recovery complying with Section E 503.5.10.1.
[ASHRAE 90.1:6.5.3.8]
E 503.5.6.8 Occupied-Standby Controls. Zones serving only rooms that are required to have automatic partial OFF or automatic full OFF lighting controls in accordance with ASHRAE 90.1, where the Chapter 4 or ASHRAE 62.1 occupancy category permits ventilation air to be reduced to zero when
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438 2025 CALIFORNIA MECHANICAL CODE
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APPENDIX E
TABLE E 503.5.6.5(1) MINIMUM AVERAGE FULL-LOAD EFFICIENCY FOR POLYPHASE SMALL ELECTRIC MOTORS* [ASHRAE 90.1: TABLE 10.8-3] Col2 Col3 Col4 FULL-LOAD EFFICIENCY, % FULL-LOAD EFFICIENCY, % FULL-LOAD EFFICIENCY, % FULL-LOAD EFFICIENCY, % NUMBER OF POLES OPEN MOTORS OPEN MOTORS OPEN MOTORS NUMBER OF POLES 2 4 6 SYNCHRONOUS SPEED (rpm) 3600 1800 1200 MOTOR SIZE (hp) EFFICIENCY, % EFFICIENCY, % EFFICIENCY, % 0.25 65.6 69.5 67.5 0.33 69.5 73.4 71.4 0.50 73.4 78.2 75.3 0.75 76.8 81.1 81.7 1 77.0 83.5 82.5 1.5 84.0 86.5 83.8 2 85.5 86.5 N/A 3 85.5 86.9 N/A For SI units: 1 horsepower = 0.746 kW
CMC § 904.7 Medium relevance — show source text
Foam systems 904.7 Glazing 2406, 2408.2.1 Halon systems 904.9 Personnel and material hoists 3004.4
Roof tile 1504.3.1
Seismic 1704.2
Smoke control 909.3, 909.5.2, 909.10.2, 909.12.1, 909.13.3, 909.18, 909.20.7.3, 909.21.7, 1705.19 Soils1 803
Sound transmission 1208 Sprinkler protection 903.5 Structural (see Special Inspections and Tests) Wet chemical systems 904.5 Testing Agency (definition) 202 Theaters [see Assembly Occupancy (Group A), Projection Rooms and Stages and Platforms] Thermal Barrier, Foam Plastic Insulation 2603.4, 2603.5.2 Thermal-insulating Materials (See Insulation) 712 Tile 202 Ceramic (see Ceramic Tile) Fire resistance, clay or shale 721.1 Tires, Bulk Storage of 311.2 Toddler 202 Toilets and Toilet Rooms Chapters 11A and 11B, 3305 Accessible 1127A, 1134A, 11B-213,
1607.9.2
Construction/finish materials 1210 Door locking 11B-404, Chapter 29 Family or assisted-use Chapter 11B and 29 Adult changing tables 11B-249 Fixture count Chapter 29 Grab bar live loads 1607.9.2 Location Chapter 29 Partitions 1210.3
Privacy 1210.3 Public facilities Chapter 29 Signs Chapters 11A and 11B, 1143A Single user Chapter 29 Ventilation 1202.5.2.1
Tornado 1603.1.4, 1609.5, 1609.6.3,
1609.6.3.2 Tornado Shelter (see Storm Shelter)
Towers Airport traffic control 412.2 Cooling 1511.4 Location and access 3108.2
Radio 3108
Television 3108
Townhouses 101.2, 202
Toxic Materials [see High-hazard Occupancy (Group H)] Classification 307.6, 414, 415 Gas detection system 415.11.7, 421.5, 908.3
Transient 310.2, 310.4 Transient Lodging (definition) 202 Transportation 11B-810 Travel Distance Area of refuge 1009.6.1 Assembly seating 1030.7 Atrium 404.9 Balcony, exterior 1017.2.1 Care suites (Group I-2) 407.4.2, 407.4.4 Common path of travel 1006.2.1 Drinking fountains Chapter 29 Exit access 1017.2
Mall 402.8.5, 402.8.6
CMC § 803.13 Medium relevance — show source text
Interior finishes Table 803.13, 804 Live load Table 1607.1 Means of egress Corridors 1020.3
Stairway, exit access 1019
Travel distance 407, 1006.3, 1017.2,
1006.2.1
Mixed occupancies 508.3, 508.4 Occupancy exceptions 303.1.1, 303.1.2, 308.5.1, 308.5.4, 310.4.1 Plumbing fixtures Chapter 29 Risk category Table 1604.5 Standby, emergency power 2702.2 Insulation
Concealed 720.2
Duct insulation 720.1
Exposed 720.3 Fiberboard 720.1, Table 1508.2, 2303.1.6.2, 2303.1.6.3 Foam plastic (see Foam Plastics) 720.1
Loose fill 720.4, 720.6 Pipe insulation 720.1, 720.7 Reflective plastic core 2614 Roof 720.5, 1508 Sound 720, 807, 1206 Thermal 720, 807, 1508 Interior Environment Lighting 1204 Rodentproofing Appendix F Sound transmission 1206
Space dimensions 1208 Temperature control 1203 Ventilation 409.3, 414.3, 415.9.1.7,
1202.5
Yards or courts 1205.2, 1205.3 Interior Finishes Chapter 8 Acoustical ceiling systems 807, 808 Application 803.13, 804.4 Atriums 404.8 Children’s play structures 424 Covered and open mall buildings 402.6
Decorative materials 419, 802.3, 806 Floor finish 804, 805 Foam plastic insulation 2603.3, 2603.4 Foam plastic trim 806.6.1, 2604.2 Insulation 807 Light-transmitting plastics 2606 Signs 402.6.4, 2611 Site-fabricated stretch systems 803.10 Trim 806.6, 806.7 Wall and ceiling finishes 803 Wet location 1210 Intermodal Shipping Container 3114 Interpretation, Code 104.1
Jails [see Institutional (see Group I-3)] 308.5, 408 Joint Gypsum board 2508.5 Lumber sheathing 2308.11.10 Waterproofing 1805.3.3 Joints, Fire-resistant Systems 715 Special inspection 1705.18
Kiosks 402.6.2
Kitchens 303.3, 306.2 Accessibility 1133A, 11B-212 Dimensions 1209 Means of egress 1016.2 Occupant load Table 1004.5 Sinks Chapter 29
INDEX-12 2025 CALIFORNIA BUILDING CODE
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INDEX
Marquees 3106, H113 Construction 3106.5
CMC § 4.3 Medium relevance — show source text
For each phase of the work, define the roles and responsibilities for each member of the Cx team. iii. List the required Cx deliverables, reports, forms and verifications expected at each stage of the commissioning effort.
iv. Include the confirmation process for the O&M manual, systems manual and the facility operator and maintenance staff training.
4.3 Enforcement:
At their discretion, the inspector confirms demonstrated compliance at Plan Intake by: a) Receipt of a copy of the commissioning plan, or b) Receipt of a form signed by the owner or owner’s representative attesting that the Cx Plan has been completed.
Reference: 5 Functional performance testing
CALGreen Section 5.410.2.4, Functional performance testing.
5.1 Intent:
Develop and implement the functional performance tests to document, as set forth in the commissioning plan, that all components, equipment, systems and system-to-system interfaces were installed as specified, and operate according to the Owner’s Project Requirements, Basis of Design, and plans and specifications.
The following systems to be functionally tested are listed in the Basis of Design (Section 5.410.2.2 of the code):
Renewable energy systems
Landscape irrigation systems
Water reuse systems
5.2 Compliance Method:
Compliance is demonstrated by developing and implementing test procedures for each piece of commissioned equipment and interfaces between equipment and systems according to the building-specific commissioning plan. Tests should include verification of proper operation of all equipment features, each part of the sequence of operation, overrides, lockouts, safeties, alarms, occupied and unoccupied modes, loss of normal power, exercising a shutdown, startup, low load through full load (as much as is possible) and back, staging and standby functions, scheduling, energy efficiency strategies and loop tuning.
Elements of acceptable test procedures include:
Date and party—Identification of the date of the test and the party conducting the test.
Signature block—Signature of the designated commissioning lead and the equipment installing contractor attesting that the recorded test results are accurate.
Prerequisites—Any conditions or related equipment checkout or testing that needs to be completed before conducting this test.
Precautions—Identification of the risks involved to the test team members and the equipment and how to mitigate them.
Instrumentation—Listing of the instrumentation and tools necessary to complete the test.
Reference—In each procedure item, identify the source for what is being confirmed (e.g., sequence of operation ID, operating feature, specification requirement, etc.).
8-18 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE
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COMPLIANCE FORMS, WORKSHEETS AND REFERENCE MATERIAL
Test instructions—Step-by-step instructions of how to complete the test, including functions to test and the conditions under which the tests should performed.
Acceptance criteria—Measurable pass / fail criteria for each step of the test, as applicable.
Results—Expected system response and space to document the actual response, readings, results and adjustments.
Return to normal—Instructions that all systems and equipment are to be returned to their as-found state at the conclusion of the tests.
Deficiencies—A list of deficiencies and how they were mitigated.
5.3 Enforcement:
CMC § 8.13.6.2 Medium relevance — show source text
(1) Refrigerant compressors
(2) Refrigerant pumps
(3) Normally closed automatic refrigerant valves
(4) Other unclassified electrical sources of ignition with apparent power rating greater than 1 kVA, where the apparent power is the product of the circuit voltage and current rating. [ASHRAE 15:8.13.6.2] 1106.11.7 Mechanical Equipment Control. Remote control of the mechanical equipment in the refrigerating machinery room shall be provided immediately outside the machinery room door solely for the purpose of shutting down the equipment in an emergency. Ventilation fans shall be on a separate electrical circuit and have a control switch located immediately outside the machinery room door. [ASHRAE 15:8.13.7] 1106.11.8 Refrigerant Detectors. Each refrigerating machinery room in accordance with Section 1106.11 shall contain one or more refrigerant detectors in accordance with Section 1106.11.9. The detector(s) sensing element shall be located in areas where refrigerant from a leak will concentrate, with one or more set points that activate responses in accordance with Section 1106.11.10 for alarms and Section 1106.11.11 for mechanical ventilation. Multiport-type devices shall be prohibited. {ASHRAE 15:8.13.8} 1106.11.9 Refrigerant Detectors Requirements. Refrigerant detectors required by Section 1106.11 shall meet all of the following conditions:
(1) A refrigerant detector shall be capable of detecting each of the specific refrigerant designations in the machinery room.
(2) The refrigerant detector shall activate responses within a time not to exceed a limit specified in Section 1106.11.10 and Section 1106.11.11 after exposure to refrigerant concentration exceeding a limit value specified in Section 1106.11.10 and Section 1106.11.11.
(3) The refrigerant detector shall have a set point not greater than the applicable Occupational Exposure Limit (OEL) value in accordance with Table 1102.3. The applicable OEL value shall be the lowest OEL value for any refrigerant designation in the machinery room. For refrigerants that do not have an OEL value in Table 1102.3, use a value determined in accordance with the OEL as defined by ASHRAE 34 where approved by the Authority Having Jurisdiction.
(4) The refrigerant detector shall have a set point not more than the applicable Refrigerant Concentration Limit (RCL) value in accordance with Table 1102.3. The applicable RCL value shall be the lowest RCL value for any refrigerant designation in the machinery room. For refrigerants that do not have a RCL value in Table 1102.3, use a value determined in accordance with the RCL as defined by ASHRAE 34 where approved by the Authority Having Jurisdiction.
(5) The refrigerant detector shall provide a means for automatic self-testing and shall be in accordance with Section 1106.11.10.4. The refrigerant detector shall be tested during installation and annually thereafter in accordance with the fire code, or at an interval not exceeding the manufacturer’s installation instructions, whichever is less. Testing shall verify compliance with the alarm set points and response times per Section 1106.11.10 and Section 1106.11.11. [ASHRAE 15:8.13.9]
CMC § 2506.2 Medium relevance — show source text
Vertical and horizontal assemblies
2504
Wallboard Table 2506.2, 2508.2, 2508.2.1, 2508.4, 2510.5.2.1 Water-resistant backing board 2506.2, 2509.2
Habitable Space 1208 Handrails 1014 Alternating tread devices 1011.14 Assembly aisles 1030.16 Construction 1014.5, 1014.6, 1014.7 Extensions 1014.7 Glazing 2407 Graspability 1014.4 Guards 1015.3 Height 1014.2 Loads 1607.9
Location 1014.1, 1014.8, 1014.9,
1014.10
Ramps 1012.8 Stairs 1011.11
Hardboard 1403.3.2, 2303.1.7 Hardware (see Doors and Locks and Latching) Hardwood
Fastening 2304.10 Quality 2303.3 Veneer 1403.3.2 Hazardous Materials 307, 414, 415 Compliance with California Fire Code 307.2
Control areas 414.2
Explosion control 414.5.1, Table 414.5.1, 415.11.6.5, 426.1.4 Mercantile occupancies 309.2 Reporting 414.1.3 Sprinkler protection Table 414.2.5.1, Table 414.2.5.2, 415.4, 415.11.12,
903.2.5
Ventilation 414.3, 415.9.1.7, 415.11.1.6, 415.11.1.8.1, 415.11.3.2, 415.11.6.8, 415.11.7.4, 415.11.8, 415.11.11, 1202.6 Weather protection 414.6.1 Hazardous Occupancy (Group H), (see Hazardous Materials) 307, 414, 415 Alarms and detection 415.11.2, 415.11.4, 415.11.6.9, 415.11.8, 415.3, 415.5, 907.2.5, 908.1, 908.2 Area 503, 505, 506, 507, 508 Dispersing 414.5, 414.6, 415.6 Gas detection systems 415.11.7 Group provisions H-1 (detonation) 307.3, 415.6.2, 415.7, 415.6.4.1, 415.7.1 H-2 (deflagration) 307.4, 415.8, 415.9 H-3 (physical hazard) 415.10, 307.5, 415.8 H-4 (health hazard) 307.6, 415.10 H-5 (semiconductor) 307.7, 415.11 Height 415.7, 415.8.1, 415.9.1.1, 426.1.1, 503, 504, 505, 506 Incidental uses 509
CMC § 1215.0 Medium relevance — show source text
HYDRONIC SPACE HEATING . . . . . . . . . . . . . . . . . 1215.0
HYDRONICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chapter 12
Auxiliary systems . . . . . . . . . . . . . . . . . . . . . . . . 1220.0
Appliances and equipment . . . . . . . . . . . . . . . . . 1207.0
Boilers . . . . . . . . . . . . . . . . . . 1207.2, 1207.2.1, 1207.2.2
Circulators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1208.0
Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1221.7
Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210.0
Embedded piping and joints . . . . . . . . . . . . . . . . 1221.2
Expansion tanks . . . . . . . . . . . . . . . . . . . . . . . . . 1209.0
Hangers and supports. . . . . . . . . . . . . . . . . . . . . 1210.3
Heat emitters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1201.7
Heat pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1207.5
Heat sources . . . . . . . . . . . . . . . . . . . . . . . . . . . 1203.1
Heat transfer fluid . . . . . . . . . . . . . . . . . . 1201.3, 1204.7
Identification of piping . . . . . . . . . . . . . . . . . . . . . 1204.0
Installation . . . . . . . . . . . . . . . . . . . . . . . 1205.0, 1221.0
Insulation. . . . . . . . . 1201.2, 1217.8.2, 1217.10, 1220.4.7
Joints and connections . . . . . . . . . . . . . . . . . . . . 1211.0
Materials . . . . . . . . . . . . . . . . . . . . 1210.0, Table 1210.1
Protection of potable water supply . . . . . . . . . . . 1202.0
Radiant heating and cooling . . . . . . . . . . . . . . . . 1217.0
Snow melt systems . . . . . . . . . . . . . . . . 1220.4, 1220.0,
1217.8.2, Table 1220.4.2
Frequently asked questions
What is the single most important CMC rule for pumps and circulators?
Follow § 1208.1: select pumps for the actual heat transfer fluid, temperature and pressure, install them to allow service/maintenance, and follow the manufacturer’s installation instructions; motors ≤ 600V must meet CSA C22.2 No. 108 or UL 778.
Does the CMC give specific numeric clearances for pump mounting?
The chapter index shows § 1208.2 Mounting, but the detailed text of § 1208.2 was not present in the retrieved files. I cannot state any numeric clearances from the CMC until I retrieve § 1208.2.
Where does the CMC tell me how to size a pump numerically?
There is a § 1208.3 Sizing entry in the table of contents, but the detailed sizing text was not retrieved in the preview. To provide a code‑based numeric sizing method I must fetch § 1208.3.
Is it okay to rely on the pump manufacturer’s curve for sizing?
Yes — the CMC explicitly requires following the manufacturer’s installation instructions for orientation/installation (per § 1208.1). However, any code‑mandated sizing method or minimums that might be in § 1208.3 must be checked in that subsection.
Do I need to document motor listings for inspection?
Yes — if the pump motor is rated 600V or less, it must comply with CSA C22.2 No. 108 or UL 778 per § 1208.1; keep listing/certification information for plan review and inspection.
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