Title 24 · California Energy Code

What nonresidential/service piping insulation requirements apply (first 8 feet and recirculation)?

Q: Which exact clause requires insulating the first 8 feet of piping?

The requirement is in § 120.3(a)3.B , which mandates insulating the first 8 feet of hot and cold outlet piping for nonrecirculating storage systems (including piping between a storage tank and a heat trap).

Q: Does the rule require insulation on recirculation return piping as well as supply?

Yes — § 120.3(a)3.A explicitly covers recirculating system piping, including the supply and return piping to the water heater .

For nonresidential and hotel/motel buildings, the California Energy Code **§ 120.3** requires insulation on recirculating domestic hot‑water piping (supply and return) and the **first 8 feet** of outlet piping on nonrecirculating storage systems; required thicknesses come from Table 120.3‑A‑1/A‑2 and depend on fluid temperature, pipe diameter, and insulation conductivity, with calculation guidance and limited exceptions provided in § 120.3(c).

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Last reviewed: July 6, 2026

What the code requires — plain English with the controlling §

Nonresidential and hotel/motel buildings must insulate specified piping (including recirculating service‑water piping and the first 8 feet of outlet piping for nonrecirculating storage systems) to the minimum thickness or R‑value shown in the tables in § 120.3. The exact thickness depends on the piping’s normal operating temperature, the pipe diameter, and the insulation material conductivity; where a material falls outside the table conductivity range, an equation in § 120.3(c) is used to calculate minimum thickness.

The single most important rule: Insulate recirculation piping (supply + return) and the first 8 feet of outlet piping on nonrecirculating storage systems to the minimum thickness called out by § 120.3(c) and Table 120.3‑A‑1 / A‑2.

Requirements in detail

Which piping is covered (summary)

Recirculating service water‑heating piping, including the supply and return to the water heater — mandatory. § 120.3(a)3.A.
The first 8 feet of hot and cold outlet piping (including piping between storage tank and heat trap) for nonrecirculating storage systems — mandatory. § 120.3(a)3.B.
Other piping types required to be insulated under § 120.3 include space‑heating/cooling fluid distribution and process heating/cooling piping (see § 120.3(a)1–5).

Minimum thickness / R‑value

The insulation thickness (or equivalent R‑value) is taken from Table 120.3‑A‑1 and Table 120.3‑A‑2 and depends on:
- Fluid operating temperature range,
- Nominal pipe diameter, and
- Insulation conductivity at the table mean temperature.
  These table requirements are invoked by § 120.3(c). If a chosen insulation’s conductivity is outside the table range, use the minimum thickness equation in § 120.3(c) to size the insulation.
Insulation conductivity must be determined per ASTM C335 at the mean temperature shown in the tables. § 120.3(c).

Decision‑relevant quick reference (examples extracted from Table 120.3‑A entries; use the table in the code for full ranges and other temperatures):

Piping condition	Fluid temp range used for table lookup	Typical thickness (example)	Code reference
Recirculating service water (supply & return) or first 8 ft of outlet piping (nonrecirculating)	105–140 °F (common domestic hot water design)	<1" nominal: 1.0 in; 1–1.5": 1.5 in; 1.5–4": 2.0 in	§ 120.3(a), § 120.3(c) — see Table 120.3‑A‑1 / A‑2
Recirculating service water (same)	Same temp row — equivalent R‑values	R ≈ 7.7 (for <1"), 12.5 (for 1–1.5"), 16 (for 1.5–4")	§ 120.3(c) and Table 120.3‑A‑1 (R‑value column)

Notes on the table values:

The table contains multiple temperature rows (e.g., below 40°F, 40–60°F, 105–140°F, above 350°F) and different conductivity ranges; pick the appropriate fluid temperature row and the column matching the nominal pipe diameter to read required thickness or R‑value. § 120.3(c).
If the insulation product’s conductivity is outside the range shown for the selected table row, use the MINIMUM INSULATION THICKNESS EQUATION in § 120.3(c) to compute required thickness.

Insulation protection and installation rules

Pipe insulation exposed to weather must have an outdoor‑suitable cover that is water‑retardant and protects from solar degradation; adhesive tape may not be used as the protective cover. § 120.3(b)1.
Chilled‑water and refrigerant suction piping located outside conditioned space must include or be protected by a Class I or Class II vapor retarder; all joints and penetrations must be sealed. § 120.3(b)2.
Pipe insulation on appurtenances must be continuous and seams sealed; pipe supports and clamps should be attached outside rigid insulation to avoid thermal bridging (applies more specifically in related multifamily text but reflects the same continuity principle referenced in the code).

Exceptions & special cases

Design temperature 60–105 °F: Piping that conveys fluids with a design operating temperature range between 60 °F and 105 °F is exempt from § 120.3 insulation requirements. (Exception 2 to § 120.3).
No net building energy impact: Where leaving piping uninsulated would not increase building source energy use, the insulation requirement may be waived (Exception 3 to § 120.3).
Framing penetrations: Piping that penetrates framing members need not be insulated for the penetration distance; metal‑to‑metal contact at metal framing must be avoided with grommets, plugs, wrapping, or other insulating materials (Exception 4 to § 120.3).
Process equipment & components: Fluid pumps, steam traps, blow‑off valves, and piping within process equipment are exempt (Exception 5). Valves, strainers, coil U‑bends, and air separators are exempt if they have at least 0.5 inch insulation (Exception 6).
Factory‑installed piping inside certified space‑conditioning equipment may be exempt (Exception 1 to § 120.3).

If in doubt about whether an exemption applies, document the technical basis (temperature, energy modeling showing no source energy penalty, or manufacturer certification) for inspection.

Common mistakes

Assuming all hot water piping everywhere must be insulated to the same thickness — the code ties thickness to temperature range and pipe diameter, not a single universal thickness. Refer to Table 120.3‑A‑1 / A‑2 and § 120.3(c).
Forgetting to insulate the first 8 feet of outlet piping on nonrecirculating storage systems (including piping between tank and heat trap). This is explicitly required in § 120.3(a)3.B.
Using an insulation product whose conductivity is outside the table range and failing to calculate required thickness with the equation in § 120.3(c).
Using adhesive tape as the primary weather or UV protection for outdoor pipe insulation — the code prohibits adhesive tape as the protective cover. § 120.3(b)1.
Missing the vapor‑retarder requirement on chilled/refrigerant suction piping located outside conditioned space. § 120.3(b)2.

Worked example — step‑by‑step

Scenario: Hotel recirculation loop (supply and return) with nominal pipe size 1.25 inches (nominal between 1 and 1.5 in), operating water temperature 120 °F.

Identify the applicable §: recirculating service water piping is covered by § 120.3(a)3.A.
Select the table temperature row: 105–140 °F (120 °F falls in this row). Use Table 120.3‑A‑1 / A‑2 as required by § 120.3(c).
Read the nominal diameter column: for 1–1.5 in nominal pipe the table shows 1.5 in insulation thickness (and an equivalent R ≈ 12.5) for the 105–140 °F row.
Confirm insulation conductivity: if the chosen insulation has conductivity within the table’s listed conductivity range for that row (e.g., 0.22–0.28 Btu·in/h·ft²·°F), install 1.5 in thickness. If the product’s conductivity is outside that range, calculate T with the MINIMUM INSULATION THICKNESS EQUATION in § 120.3(c).

Result: For the typical insulation conductivity range, the 1.25‑inch recirculation pipe at 120 °F requires 1.5 inches of insulation per § 120.3(c) and Table 120.3‑A.

Related provisions (quick list)

§ 120.3(a) — General piping types that must be insulated (space conditioning, service water‑heating, process piping).
§ 120.3(b) — Insulation protection (outdoor cover, vapor retarders, sealing).
§ 120.3(c) — Insulation thickness, R‑value requirements, and minimum‑thickness equation.
Exception clauses to § 120.3 (Exceptions 1–6) — exemptions for factory piping, 60–105 °F fluids, process equipment, penetrations, etc.

Code references

Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:

§ 25218.5 High relevance — show source text
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 120.3—REQUIREMENTS FOR PIPE INSULATION

Nonresidential and hotel/motel buildings shall comply with the applicable requirements of Sections 120.3(a) through 120.3(c).

(a) General requirements. The piping conditions listed below for space-conditioning, service water-heating, and process heating and process cooling systems piping with fluid normal operating temperatures listed in Table 120.3-A-1 or Table 120.3-A2, and the fluid distribution system, shall have at least the amount of insulation specified in Subsection (c):
1. Space cooling systems. All refrigerant suction, chilled water, and brine fluid distribution systems.
2. Space heating systems. All refrigerant suction, steam, steam condensate and hot water fluid distribution systems.
3. Service water-heating systems. A. Recirculating system piping, including the supply and return piping to the water heater. B. The first 8 feet of hot and cold outlet piping, including piping between a storage tank and a heat trap, for a nonrecirculating storage system.
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C. Pipes that are externally heated. 4. Process heating system piping. All refrigerant, steam, steam condensate and hot water fluid distribution systems for heating a process unrelated to space conditioning or service water heating. 5. Process cooling system piping. All refrigerant suction, chilled water, and brine fluid distribution systems for cooling a process unrelated to space conditioning.

Insulation conductivity shall be determined in accordance with ASTM C335 at the mean temperature listed in Table 120.3-A1 or Table 120.3-A2, and shall be rounded to the nearest [1] / 100 Btu-inch per hour per square foot per °F. Fluid distribution systems include all elements that are in series with the fluid flow, such as pipes, fittings, pumps, valves, strainers, coil u-bends, and air separators, but not including elements that are not in series with the fluid flow, such as expansion tanks, fill lines, chemical feeders, and drains.

Exception to Section 120.3(a)2: Heat pump refrigerant vapor line shall be installed with a minimum of 0.5-inch-thick or R-3.0 insulation for nonresidential buildings and 0.75-inch-thick or R-6.0 insulation for residential buildings. No insulation is required on the refrigerant liquid line.

(b) Insulation protection. Pipe insulation shall be protected from damage due to sunlight, moisture, equipment maintenance and wind. Protection shall, at minimum, include the following:
1. Pipe insulation exposed to weather shall be protected by a cover suitable for outdoor service. The cover shall be water retardant and provides shielding from solar radiation that can cause degradation of the material. Adhesive tape shall not be used to provide this protection.
§ 6.8 High relevance — show source text
(b) Solar water-heating systems and collectors shall be certified and rated by the Solar Rating and Certification Corporation (SRCC), the International Association of Plumbing and Mechanical Officials, Research and Testing (IAPMO R&T), or a listing agency that is approved by the Executive Director.

(c) Instantaneous water heaters with an input rating greater than 6.8 kBTU/hr (2kW) shall meet the requirements of Section 110.3(c)6.

(d) Commercial boilers
1. Combustion air positive shut-off shall be provided on all newly installed boilers as follows: A. All boilers with an input capacity of 2.5 MMBtu/h (2,500,000 Btu/h) and above, in which the boiler is designed to operate with a nonpositive vent static pressure. B. All boilers where one stack serves two or more boilers with a total combined input capacity per stack of 2.5 MMBtu/h (2,500,000 Btu/h).
2. Boiler combustion air fans with motors 10 horsepower or larger shall meet one of the following for newly installed boilers: A. The fan motor shall be driven by a variable speed drive, or B. The fan motor shall include controls that limit the fan motor demand to no more than 30 percent of the total design wattage at 50 percent of design air volume.
3. Newly installed boilers with an input capacity 5 MMBtu/h (5,000,000 Btu/h) and greater shall maintain excess (stack-gas) oxygen concentrations at less than or equal to 5.0 percent by volume on a dry basis over firing rates of 20 percent to 100 percent. Combustion air volume shall be controlled with respect to firing rate or flue gas oxygen concentration. Use of a common gas and combustion air control linkage or jack shaft is prohibited. Exception to Section 160.4(d)3: Boilers with steady state full-load thermal combustion efficiency 90 percent or higher.
(e) Pipe insulation

All piping for multifamily domestic hot water systems shall be insulated and meet the applicable requirements in Items 1 through 3 below:
1. General requirements. A. The first 8 feet of inlet cold water piping from the storage tanks, including piping between a storage tank and a heat trap, shall be insulated. B. Insulation on the piping and domestic hot water system appurtenances shall be continuous. C. Pipe supports, hangers, and pipe clamps shall be attached on the outside of rigid pipe insulation to prevent thermal bridges. D. All pipe insulation seams shall be sealed. E. Insulation for pipe elbows shall be mitered, preformed, or site fabricated with PVC covers. F. Insulation for tees shall be notched, preformed, or site fabricated with PVC covers.
G. Extended stem isolation valves shall be installed.

H. All plumbing appurtenances on hot water piping from a heating source to heating plant, at the heating plant, and distribution supply and return piping shall be insulated to meet the following requirements: i. Where the outer diameter of the appurtenance is less than the outer diameter of the insulated pipe that it is attached to, the appurtenance shall be insulated flush with the insulation surrounding the pipe. ii. Where the outer diameter of the appurtenance is greater than the outer diameter of the insulated pipe that it is attached to, the appurtenance shall be insulated with a minimum thickness of 1 inch. iii. The insulation shall be removable and re-installable to ensure maintenance or replacement services can be completed. iv. Valves shall be fully functional without impediment from the insulation.
§ 87.9 High relevance — show source text
9 kW) and larger| |Additions or
Alterations|Zone terminal unit such as VAV box|Where existing zones served by the same air handling,
chilled water, or hot water systems that have DDC| |Additions or
Alterations|Air handling system or fan coil|Where existing air handling system(s) and fan coil(s)
served by the same chilled or hot water plant have DDC| |Additions or
Alterations|New air handling system and all
new zones served by the system|Individual systems with design heating or cooling capacity of
300 kBtu/h and larger and supplying more than three zones and
more than 75 percent of zones are new| |Additions or
Alterations|New or upgraded chilled water plant|Where all chillers are new and plant design cooling
capacity is 300 kBtu/h (87.9 kW) and larger| |Additions or
Alterations|New or upgraded hot water plant|Where all boilers are new and plant design heating
capacity is 300 kBtu/h (87.9 kW) and larger|

(k) Optimum start/stop controls. Space conditioning systems with DDC to the zone level shall have optimum start/stop controls. The control algorithm shall, as a minimum, be a function of the difference between space temperature and occupied setpoint, the outdoor air temperature, and the amount of time prior to scheduled occupancy. Mass radiant floor slab systems shall incorporate floor temperature onto the optimum start algorithm.

Exception to Section 120.2(k): Systems that must operate continuously.

(l) HVAC hot water temperature. Zones that use hot water for space heating shall be designed for a hot water supply temperature of no greater than 130°F.

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 120.3—REQUIREMENTS FOR PIPE INSULATION

Nonresidential and hotel/motel buildings shall comply with the applicable requirements of Sections 120.3(a) through 120.3(c).

(a) General requirements. The piping conditions listed below for space-conditioning, service water-heating, and process heating and process cooling systems piping with fluid normal operating temperatures listed in Table 120.3-A-1 or Table 120.3-A2, and the fluid distribution system, shall have at least the amount of insulation specified in Subsection (c):
1. Space cooling systems. All refrigerant suction, chilled water, and brine fluid distribution systems.
2. Space heating systems. All refrigerant suction, steam, steam condensate and hot water fluid distribution systems.
3. Service water-heating systems. A. Recirculating system piping, including the supply and return piping to the water heater. B. The first 8 feet of hot and cold outlet piping, including piping between a storage tank and a heat trap, for a nonrecirculating storage system.
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NONRESIDENTIAL, HOTEL/MOTEL OCCUPANCIES, AND COVERED PROCESSES—MANDATORY REQUIREMENTS

§ 120.3 High relevance — show source text

Exception 2 to Section 120.3: Piping that conveys fluids with a design operating temperature range between 60°F and 105°F.

Exception 3 to Section 120.3: Where the heat gain or heat loss to or from piping without insulation will not increase building

source energy use.

Exception 4 to Section 120.3: Piping that penetrates framing members shall not be required to have pipe insulation for the distance of the framing penetration. Metal piping that penetrates metal framing shall use grommets, plugs, wrapping or other insulating material to assure that no contact is made with the metal framing.

Exception 5 to Section 120.3: Fluid pumps, steam traps, blow-off valves, and piping within process equipment.

Exception 6 to Section 120.3: Valves, strainers, coil u-bends, air separators with at least 0.5 inches of insulation, and piping within process equipment.

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, 25402.5, 25402.8, and 25943, Public Resources Code.

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NONRESIDENTIAL, HOTEL/MOTEL OCCUPANCIES, AND COVERED PROCESSES—MANDATORY REQUIREMENTS

TABLE 120.3-A-1—SPACE HEATING AND SERVICE WATER HEATING SYSTEMS (STEAM, STEAM CONDENSATE, REFRIGERANT, SPACE HEATING, SERVICE HOT WATER) AND PROCESS HEATING SYSTEM PIPE INSULATION THICKNESS	Col2	Col3	Col4	Col5	Col6	Col7	Col8
FLUID OPERATING TEMPERATURE RANGE (°F)	INSULATION CONDUCTIVITY (Btu·in/h·ft2· °F)	INSULATION MEAN RATING TEMPERATURE (°F)	NOMINAL PIPE DIAMETER < 1 INCH	NOMINAL PIPE DIAMETER 1 TO < 1.5 INCHES	NOMINAL PIPE DIAMETER 1.5 TO < 4 INCHES	NOMINAL PIPE DIAMETER 4 TO < 8 INCHES	NOMINAL PIPE DIAMETER 8 INCHES AND LARGER
Above 350	0.32–0.34	250	4.5 inches	5.0 inches	5.0 inches	5.0 inches	5.0 inches
Above 350	0.32–_0.

§ 0.24 High relevance — show source text
all piping in electric trace tape systems and the first 8 feet of piping from the storage tank for
nonrecirculating systems)|Service water-heating systems (recirculating sections, all piping in electric trace tape systems and the first 8 feet of piping from the storage tank for
nonrecirculating systems)|Service water-heating systems (recirculating sections, all piping in electric trace tape systems and the first 8 feet of piping from the storage tank for
nonrecirculating systems)|Service water-heating systems (recirculating sections, all piping in electric trace tape systems and the first 8 feet of piping from the storage tank for
nonrecirculating systems)|Service water-heating systems (recirculating sections, all piping in electric trace tape systems and the first 8 feet of piping from the storage tank for
nonrecirculating systems)|Service water-heating systems (recirculating sections, all piping in electric trace tape systems and the first 8 feet of piping from the storage tank for
nonrecirculating systems)|Service water-heating systems (recirculating sections, all piping in electric trace tape systems and the first 8 feet of piping from the storage tank for
nonrecirculating systems)| |Above 105|0.24-0.28|100|0.5|1.0|1.0|1.5|1.5|1.5| |Space cooling systems (chilled water, refrigerant and brine)|Space cooling systems (chilled water, refrigerant and brine)|Space cooling systems (chilled water, refrigerant and brine)|Space cooling systems (chilled water, refrigerant and brine)|Space cooling systems (chilled water, refrigerant and brine)|Space cooling systems (chilled water, refrigerant and brine)|Space cooling systems (chilled water, refrigerant and brine)|Space cooling systems (chilled water, refrigerant and brine)|Space cooling systems (chilled water, refrigerant and brine)| |40-60|0.23-0.27|75|0.5|0.5|0.5|1.0|1.0|1.0| |Below 40|0.23-0.27|75|1.0|1.0|1.5|1.5|1.5|1.5|

A6.207.6.1 For insulation with a conductivity in the range shown in Table A6.207.6-A for the applicable fluid temperature range, the insulation shall have the applicable thickness shown in Table A6.207.6-A.

A6.207.6.2 For insulation with a conductivity outside the range shown in Table A6.207.6-A for the applicable fluid temperature range, the insulation shall have a minimum thickness as calculated with Equation A6.207.6-A below.

— EQUATION A6.207.6-A INSULATION THICKNESS EQUATION

K

[-] k [-]

T = PR  1 + ------ PRt  – 1

where:

T = Minimum insulation thickness for material with conductivity K, inches.

PR = Pipe actual outside radius, inches.

t = Insulation thickness from Table A6.207.6-A, inches.

K = Conductivity of alternate material at the mean rating temperature indicated in Table A6.207.6-A, for the applicable fluid temperature range, in Btu-inch per hour per square foot per °F.
§ 160.4 High relevance — show source text
Exception to Section 160.4(d)3: Boilers with steady state full-load thermal combustion efficiency 90 percent or higher.

(e) Pipe insulation

All piping for multifamily domestic hot water systems shall be insulated and meet the applicable requirements in Items 1 through 3 below:
1. General requirements. A. The first 8 feet of inlet cold water piping from the storage tanks, including piping between a storage tank and a heat trap, shall be insulated. B. Insulation on the piping and domestic hot water system appurtenances shall be continuous. C. Pipe supports, hangers, and pipe clamps shall be attached on the outside of rigid pipe insulation to prevent thermal bridges. D. All pipe insulation seams shall be sealed. E. Insulation for pipe elbows shall be mitered, preformed, or site fabricated with PVC covers. F. Insulation for tees shall be notched, preformed, or site fabricated with PVC covers.
G. Extended stem isolation valves shall be installed.

H. All plumbing appurtenances on hot water piping from a heating source to heating plant, at the heating plant, and distribution supply and return piping shall be insulated to meet the following requirements: i. Where the outer diameter of the appurtenance is less than the outer diameter of the insulated pipe that it is attached to, the appurtenance shall be insulated flush with the insulation surrounding the pipe. ii. Where the outer diameter of the appurtenance is greater than the outer diameter of the insulated pipe that it is attached to, the appurtenance shall be insulated with a minimum thickness of 1 inch. iii. The insulation shall be removable and re-installable to ensure maintenance or replacement services can be completed. iv. Valves shall be fully functional without impediment from the insulation.

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MULTIFAMILY BUILDINGS—MANDATORY REQUIREMENTS
1. Insulation thickness. All piping for multifamily domestic hot water systems shall meet the insulation thickness requirements specified in Table 160.4-A. A. For insulation conductivity in the range shown in Table 160.4-A for the applicable fluid temperature range, the insulation shall have the applicable minimum thickness or R -value shown in Table 160.4-A. B. If the insulation conductivity falls outside the range provided in Table 160.4-A applicable fluid temperature range, the insulation shall meet a minimum R -value as indicated in Table 160.4-A. Or, it can have a thickness determined using Equation 160.4-A.
(Equation 160.4-A)

K

[-] k [-]

T = PR  1 + ------ PRt  – 1

|TABLE 160.
§ 141.0 High relevance — show source text
Exception 2 to Section 141.0(a): Where an existing system with electric reheat is expanded by adding variable air volume (VAV) boxes to serve an addition, total electric reheat capacity may be expanded so that the total capacity does not exceed 150 percent of the existing installed electric heating capacity in any one permit, and the system need not comply with Section 140.4(g). Additional electric reheat capacity in excess of 150 percent of the existing installed electric heating capacity may be added subject to the requirements of Section 140.4(g).

Exception 3 to Section 141.0(a): Duct sealing. When ducts are extended from an existing duct system to serve the addition, the existing duct system and the extended ducts shall meet the applicable requirements specified in Section 141.0(b)2D.

Exception 4 to Section 141.0(a): Additions that increase the area of the roof by 2,000 square feet or less are not required to comply with Section 110.10.

Exception 5 to Section 141.0(a): A gas hot water boiler system with a total system input of at least 1 MMBtu/h but no more than 10 MMBtu/h added to an existing building is not required to comply with Section 140.4(k)8.

Exception 6 to Section 141.0(a): A gas service water-heating system with a total system input of at least 1 MMBtu/h added to an existing building is not required to comply with Section 140.5(c).

Exception 7 to Section 141.0(a) : Section 140.4(a)2 shall not apply to new space-conditioning systems or components.

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NONRESIDENTIAL AND HOTEL/MOTEL OCCUPANCIES— ADDITIONS, ALTERATIONS AND REPAIRS

(b) Alterations. Alterations to components of existing nonresidential, hotel/motel, or relocatable public school buildings, including alterations made in conjunction with a change in building occupancy to a nonresidential, high-rise residential or hotel/motel occupancy shall meet Item 1, and either Item 2 or 3 below:
1. Mandatory requirements. Altered components in a nonresidential or hotel/motel building shall meet the minimum requirements in this section. A. Roof/ceiling insulation. The opaque portions of the roof/ceiling that separate conditioned spaces from unconditioned spaces or ambient air shall meet the requirements of Section 141.0(b)2Bii. B. Wall insulation. For the altered opaque portion of walls separating conditioned spaces from unconditioned spaces or ambient air shall meet the applicable requirements of Items 1 through 4 below:
2. Metal building. A minimum of R-13 insulation between framing members, or the area-weighted average U factor of the wall assembly shall not exceed U-0.113.
3. Metal framed. A minimum of R-13 insulation between framing members, or the area-weighted average U- factor of the wall assembly shall not exceed U-0.217.
4. Wood framed and others. A minimum of R-11 insulation between framing members, or the area-weighted average U -factor of the wall assembly shall not exceed U-0.110.
5. **Spandrel panels and glass curtain walls.
§ 120.3 High relevance — show source text
All penetrations and joints shall be sealed. 3. Pipe insulation buried below grade must be installed in a water proof and noncrushable casing or sleeve.

(c) Insulation thickness.
1. For insulation with a conductivity in the range shown in Table 120.3-A-1 or Table 120.3-A-2 for the applicable fluid temperature range, the insulation shall have the applicable minimum thickness or R -value shown in Table 120.3-A1 or Table 120.3-A-2.
2. For insulation with a conductivity outside the range shown in Table 120.3-A-1 or Table 120.3-A-2 for the applicable fluid temperature range, the insulation shall have a minimum R -value shown in Table 120.3-A-1 or Table 120.3-A-2 or thickness as calculated:
MINIMUM INSULATION THICKNESS EQUATION

K

[-] k [-]

T = PR  1 + ------ PRt  – 1

where:

T = minimum insulation thickness for material with conductivity K, inches.

PR = pipe actual outside radius, inches.

t = insulation thickness from Table 120.3-A 1 or Table 120.3-A2, inches.

K = conductivity of alternate material at the mean rating temperature indicated in Table 120.3-A for the applicable fluid temperature range, in Btu-inch per hour per square foot per °F.

k = The lower value of the conductivity range listed in Table 120.3-A for the applicable fluid temperature range, Btu-inch per hour per square foot per °F.

Exception 1 to Section 120.3: Factory-installed piping within space-conditioning equipment certified under Section 110.1 or 110.2.

Exception 2 to Section 120.3: Piping that conveys fluids with a design operating temperature range between 60°F and 105°F.

Exception 3 to Section 120.3: Where the heat gain or heat loss to or from piping without insulation will not increase building

source energy use.

Exception 4 to Section 120.3: Piping that penetrates framing members shall not be required to have pipe insulation for the distance of the framing penetration. Metal piping that penetrates metal framing shall use grommets, plugs, wrapping or other insulating material to assure that no contact is made with the metal framing.

Exception 5 to Section 120.3: Fluid pumps, steam traps, blow-off valves, and piping within process equipment.

Exception 6 to Section 120.3: Valves, strainers, coil u-bends, air separators with at least 0.5 inches of insulation, and piping within process equipment.

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, 25402.5, 25402.8, and 25943, Public Resources Code.

76 2025 CALIFORNIA ENERGY CODE

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NONRESIDENTIAL, HOTEL/MOTEL OCCUPANCIES, AND COVERED PROCESSES—MANDATORY REQUIREMENTS

|TABLE 120.
§ 170.1 High relevance — show source text
1. Central systems. For systems serving multiple dwelling units, the water-heating system shall meet the applicable requirement of A through F, or shall meet the performance compliance requirements of Section 170.1: A. For heat pump water-heating systems serving multiple dwelling units, the water-heating system shall be installed according to the manufacturer’s design and installation guidelines and meet the following requirements, or meet the requirements of NEEA Advanced Water Heater Specification for commercial heat pump water heater Tier 2 or higher: i. The primary heat pump water heater shall be a single-pass heat pump water heater. ii. The hot water return from the recirculation loop shall connect to a recirculation loop tank and shall not directly connect to the primary heat pump water heater inlet or the primary thermal storage tanks. iii. The fuel source for the recirculation loop tank shall be electricity. iv. The primary storage tank temperature setpoint shall be at least 135°F. v. The recirculation loop tank temperature setpoint shall be at least 10°F lower than the primary thermal storage tank temperature setpoint. vi. The minimum heat pump water heater compressor cut-off temperature shall be equal to or lower than 40°F ambient air temperature. vii. Design documentation shall be provided in accordance with JA14.4. B. For gas or propane systems serving multiple dwelling units, the water-heating system that includes the following components shall be installed: i. For Climate Zones 1 through 9, gas service water-heating systems with a total installed gas water-heating input capacity of 1 MMBtu/h or greater shall have gas service water-heating equipment with a minimum thermal efficiency of 90 percent. Multiple units are allowed to meet this requirement with an input capacity-weighted average of at least 90 percent. Exception 1 to Section 170.2(d)Bi: Individual gas water heaters with input capacity at or below 100,000 Btu/h shall not be included in the calculations of the total system input or total system efficiency. Exception 2 to Section 170.2(d)Bi: If 25 percent of the annual water-heating requirement is provided by sitesolar energy or site-recovered energy. ii. A solar water-heating system meeting the installation criteria specified in Reference Residential Appendix RA4 and with a minimum solar savings fraction of either a. or b. below: a. A minimum solar savings fraction of 0.20 in Climate Zones 1 through 9 or a minimum solar savings fraction of 0.35 in Climate Zones 10 through 16; or b. A minimum solar savings fraction of 0.15 in Climate Zones 1 through 9 or a minimum solar savings fraction of 0.30 in Climate Zones 10 through 16. In addition, a drain water heat recovery system that is field verified as specified in the Reference Appendix RA3.6.9. C. All hot water piping shall be sized in accordance with the California Plumbing Code Appendix M. D. The central system shall have a recirculation system with a mechanical or digital thermostatic master mixing valve on each distribution supply and return loop, and meet the requirements specified in the Residential Reference Appendix RA4.4.19.
Exception to Section 170.2(d)2D : Buildings with eight or fewer dwelling units. E. Insulation for hot water pipes and plumbing appurtenances shall be field verified as specified in Residential Reference Appendix RA3.6.3. F. A water-heating system serving multiple dwelling units determined by the Executive Director to use no more energy than the one specified in Subsection A or B above.

2025 CALIFORNIA ENERGY CODE 257
§ 0.5 High relevance — show source text
in.|≤ 100 sq. in. =
D-H-90
>100 sq. in.=
D-H-W-90|Not
Permitted|2|Not
Permitted|W-120| |Double fire walls
constructed in
accordance with
NFPA 221|2|1|1|100 sq. in.|≤ 100 sq. in. =
D-H-60
> 100 sq. in. =
D-H-W-60|Not
Permitted|1|Not
Permitted|W-60| |Enclosures for
shafts, interior exit
stairways and inte-
rior exit ramps.|2|2|11/ 2|100 sq. in.b|≤100 sq. in. =
D-H-90
> 100 sq. in.=
D-H-T-W-90|Not
Permitted|2|Not
Permitted|W-120| |Horizontal exits in
fire wallsg|4|4|3|100 sq. in.|≤100 sq. in. =
D-H-180
> 100 sq. in.=
D-H-W-240|Not
Permitted|4|Not
Permitted|W-240| |Horizontal exits in
fire wallsg|3|3|3d|100 sq. in.|≤100 sq. in. =
D-H-180
> 100 sq. in.=
D-H-W-180|Not
Permitted|3|Not
Permitted|W-180| |Fire barriers having
a required fire-
resistance rating of
1 hour: Enclosures
for shafts, exit
access stairways,
exit access ramps,
interior exit stair-
ways and interior
exit ramps; and exit
passageway walls|1|1|1|100 sq. in.|≤100 sq. in. =
D-H-60
>100 sq. in.=
D-H-T-W-60|Not
Permitted|1|Not
Permitted|W-60| |||||||Fire protection|Fire protection||| |Other fire barriers|1|1|3/ 4|Maximum
size tested|D-H-45|3/ 4
h|3/ 4
h|D-H-45h|D-H-45h| |Fire partitions:
Corridor walls|1|1|1/ 3
a|Maximum
size tested|D-20|3/ 4
a|3/ 4
a|D-H-OH-45|D-H-OH-45| |Fire partitions:
Corridor walls|0.5|0.5|1/ 3
a|Maximum
size tested|D-20|1/ 3|1/ 3|D-H-OH-20|D-H-OH-20|

7-28 2025 CALIFORNIA BUILDING CODE

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

FIRE AND SMOKE PROTECTION FEATURES

|TABLE 716.1(2)—OPENING FIRE PROTECTION ASSEMBLIES,
§ 120.3. High relevance — show source text
(d) Process piping. Newly installed process heating and process cooling system piping and pipes relocated as part of an alteration shall meet the requirements of Section 120.3.

NOTE: For alterations that change the occupancy classification of the building, the requirements of Section 141.1 apply to the occupancy that will exist after the alterations.

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.

2025 CALIFORNIA ENERGY CODE 157

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

158 2025 CALIFORNIA ENERGY CODE

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

7 SINGLE-FAMILY RESIDENTIAL BUILDINGS—

MANDATORY FEATURES AND DEVICES

SECTION 150.0—MANDATORY FEATURES AND DEVICES

Single-family residential buildings shall comply with the applicable requirements of Sections 150(a) through 150.0(v).

NOTE: The requirements of Sections 150.0(a) through 150.0(v) apply to newly constructed buildings. Sections 150.2(a) and 150.2(b) specify which requirements of Sections 150.0(a) through 150.0(v) also apply to additions or alterations.

(a) Roof deck, ceiling and rafter roof insulation. The opaque portions of roof decks separating attic spaces from ambient air, and ceilings or rafter roofs separating conditioned spaces from unconditioned spaces or ambient air, shall meet the requirements of Items 1 through 4 below:
1. In Climate Zones 4 and 8 through 16, roof decks in newly constructed attics that are above conditioned space shall be insulated to achieve an area-weighted average U -factor not exceeding U-0.184. Exception 1 to Section 150.0(a)1:
i. The space-conditioning system air handler and ducts are located entirely in conditioned space below the ceiling separating the occupiable space from the attic; or ii. The space-conditioning system air handler is located in unconditioned space and has 12 linear feet or less of supply duct, including the length of the air handler and the plenum, located in unconditioned space, with all other portions of the supply ducts located in conditioned space below the ceiling separating the occupiable space from the attic; or iii. The space-conditioning system is a ductless system. Exception 2 to Section 150.0(a)1: Space-conditioning duct systems buried within insulation in an attic that complies using Section 150.1(b) and is verified according to RA 3.1.4.1. 2. Ceilings and rafter roofs shall be insulated to achieve an area-weighted average U -factor not exceeding U-0.043 or shall be insulated between wood-framing members with insulation resulting in an installed thermal resistance of R-22 or greater for the insulation alone.
§ 907.2.24.2 High relevance — show source text
907.2.24.2 Production locations — solid-ceiling sets and platforms. Where required by Chapter 48 of the California Fire Code in buildings with existing fire protection systems and where production intends to construct solid-ceiling sets over 600 square feet (55.7 m [2] ) in area, and platforms over 600 square feet (55.7 m [2] ) in area and which exceed 3 feet (914 mm) in height shall be protected by an approved heat detector system. Heat detectors shall be spaced 30 feet (9144 mm) on center or as required by the manufacturer's installation instructions. The fire alarm system shall be connected to an approved supervising station in accor- dance with Section 907.6.6 or a local alarm which will give an audible signal at a constantly attended location.

907.2.24.3 Fire alarm control units. Fire alarm control units shall be California State Fire Marshal listed and shall be utilized in accordance with their listing. Control units are permitted to be temporarily supported by sets, platforms or pedestals.

907.2.24.4 Heat detectors.

907.2.24.4.1 Heat detection required by this section shall be defined as a portable system as it is intended to be reinstalled when platforms or sets are changed.

907.2.24.4.2 Heat detectors shall be secured to standard outlet boxes and are allowed to be temporarily supported by sets, plat- forms or pedestals.

907.2.24.4.3 Heat detectors shall be provided for solid-ceiling sets and platforms where required by Sections 4805.3 and 4811.14.

907.2.25 Group C occupancies (organized camps).

907.2.25.1 General. Every building and structure used or intended for sleeping purposes shall be provided with an automatic smoke detection system.

Exceptions:

1. Buildings and structures in existence and in operation prior to January 1, 1985. 2. Tents, tent structures and buildings and structures that do not exceed 25 ft (7620 mm) in any lateral dimensions and where such building or structure is not more than one story.

907.2.25.2 Camp fire alarm. Every organized camp shall provide and maintain audible appliances, or devices suitable for sound- ing a fire alarm. Such audible appliances or devices may be of any type acceptable to the enforcing agency provided they are distinctive in tone from all other signaling devices or systems and shall be audible throughout the camp premises. When an auto- matic fire alarm system is provided, as required by Section 450.6.6 of the California Building Code, all audible appliances required by this section shall be of the same type as that used in the automatic system.

2025 CALIFORNIA BUILDING CODE 9-35

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

FIRE PROTECTION AND LIFE SAFETY SYSTEMS

907.2.26 Fixed-guideway and passenger rail transit systems fire alarm and communication systems.

Frequently asked questions

Which exact clause requires insulating the first 8 feet of piping?

The requirement is in § 120.3(a)3.B, which mandates insulating the first 8 feet of hot and cold outlet piping for nonrecirculating storage systems (including piping between a storage tank and a heat trap).

Does the rule require insulation on recirculation return piping as well as supply?

Yes — § 120.3(a)3.A explicitly covers recirculating system piping, including the supply and return piping to the water heater.

What if my insulation product’s conductivity is different than the table’s stated range?

If the product’s conductivity falls outside the table range, use the MINIMUM INSULATION THICKNESS EQUATION in § 120.3(c) to calculate the required thickness.

Are valves and fittings exempt?

Some appurtenances are exempt or treated specially: valves, strainers, coil U‑bends, and air separators are exempt only if they already have at least 0.5 inch of insulation; otherwise they must be insulated or covered as required (Exception 6 to § 120.3).

Can I leave 60–105 °F piping uninsulated?

Yes — piping that conveys fluids with a design operating temperature range between 60 °F and 105 °F is excluded from § 120.3 insulation requirements (Exception 2).

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