Section 120.3
California Energy Code (Title 24, Part 6) · 2022 edition · updated 2026-09-12 · California
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 and service water-heating systems with fluid normal operating temperatures listed in Table 120.3-A, shall have at least the amount of insulation specified in Subsection (c):
Space cooling systems. All refrigerant suction, chilled water, and brine fluid distribution systems.
Space heating systems. All refrigerant, steam, steam condensate and hot water fluid distribution systems.
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, includ ing piping between a storage tank and a heat trap, for a nonrecirculating storage system.
C. Pipes that are externally heated.
Insulation conductivity shall be determined in accordance with ASTM C335 at the mean temperature listed in Table 120.3-A, 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, 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.
(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:
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.
Pipe insulation covering chilled water piping and refrigerant suction piping located outside the condi
T = PR 1 + ------- t PR
K
-- k -
= PR 1 + ------- - 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, 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.
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.
78 2022 CALIFORNIA ENERGY CODE
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NONRESIDENTIAL, HOTEL/MOTEL OCCUPANCIES, AND COVERED PROCESSES—MANDATORY REQUIREMENTS
TABLE 120.3-A PIPE INSULATION THICKNESS
| FLUID OPERATING TEMPERATURE RANGE (°F) |
INSULATION CONDUCTIVITY | NOMINAL PIPE DIAMETER (in inches) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| FLUID OPERATING TEMPERATURE RANGE (°F) |
CONDUCTIVITY (in Btu·in/ |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
| FLUID OPERATING TEMPERATURE RANGE (°F) |
CONDUCTIVITY (in Btu·in/ |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
< 1 | < 1 | 1 to < 1.5 | 1 to < 1.5 | 1.5 to < 4 | 4 to < 8 | 8 and larger |
| Space heating and Service Water Heating Systems (Steam, Steam Condensate, Refrigerant, Space Heating, Service Hot Water) |
Space heating and Service Water Heating Systems (Steam, Steam Condensate, Refrigerant, Space Heating, Service Hot Water) |
Space heating and Service Water Heating Systems (Steam, Steam Condensate, Refrigerant, Space Heating, Service Hot Water) |
Space heating and Service Water Heating Systems (Steam, Steam Condensate, Refrigerant, Space Heating, Service Hot Water) |
Minimum Pipe Insulation Required (Thickness in inches or R-value) | Minimum Pipe Insulation Required (Thickness in inches or R-value) | Minimum Pipe Insulation Required (Thickness in inches or R-value) | Minimum Pipe Insulation Required (Thickness in inches or R-value) | Minimum Pipe Insulation Required (Thickness in inches or R-value) | Minimum Pipe Insulation Required (Thickness in inches or R-value) | Minimum Pipe Insulation Required (Thickness in inches or R-value) |
| Above 350 | 0.32–0.34 | 250 | Inches | 4.5 | 4.5 | 5.0 | 5.0 | 5.0 | 5.0 | 5.0 |
| Above 350 | 0.32–0.34 | 250 | R-value | R-37 | R-37 | R-41 | R-41 | R-37 | R-27 | R-23 |
| 251–350 | 0.29–0.32 | 200 | Inches | 3.0 | 3.0 | 4.0 | 4.0 | 4.5 | 4.5 | 4.5 |
| 251–350 | 0.29–0.32 | 200 | R-value | R-24 | R-24 | R-34 | R-34 | R-35 | R-26 | R-22 |
| 201–250 | 0.27–0.30 | 150 | Inches | 2.5 | 2.5 | 2.5 | 2.5 | 2.5 | 3.0 | 3.0 |
| 201–250 | 0.27–0.30 | 150 | R-value | R-21 | R-21 | R-20 | R-20 | R-17.5 | R-17 | R-14.5 |
| 141–200 | 0.25–0.29 | 125 | Inches | 1.5 | 1.5 | 1.5 | 1.5 | 2.0 | 2.0 | 2.0 |
| 141–200 | 0.25–0.29 | 125 | R-value | R-11.5 | R-11.5 | R-11 | R-11 | R-14 | R-11 | R-10 |
| 105–140 | 0.22–0.28 | 100 | Inches | 1.0 | 1.0 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 |
| 105–140 | 0.22–0.28 | 100 | R-value | R-7.7 | R-7.7 | R-12.5 | R-12.5 | R-11 | R-9 | R-8 |
| FLUID OPERATING TEMPERATURE RANGE (°F) |
INSULATION CONDUCTIVITY | INSULATION CONDUCTIVITY | Nominal Pipe Diameter (in inches) | Nominal Pipe Diameter (in inches) | Nominal Pipe Diameter (in inches) | Nominal Pipe Diameter (in inches) | Nominal Pipe Diameter (in inches) | Nominal Pipe Diameter (in inches) | Nominal Pipe Diameter (in inches) | |
| FLUID OPERATING TEMPERATURE RANGE (°F) |
CONDUCTIVITY (in Btu·in/ |
MEAN RATING TEMPERATURE (°F) |
MEAN RATING TEMPERATURE (°F) |
< 1 | < 1 | 1 to < 1.5 | 1 to < 1.5 | 1.5 to < 4 | 4 to < 8 | 8 and larger |
| 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) | Minimum Pipe Insulation Required (Thickness in inches or R-value)1 | Minimum Pipe Insulation Required (Thickness in inches or R-value)1 | Minimum Pipe Insulation Required (Thickness in inches or R-value)1 | Minimum Pipe Insulation Required (Thickness in inches or R-value)1 | Minimum Pipe Insulation Required (Thickness in inches or R-value)1 | Minimum Pipe Insulation Required (Thickness in inches or R-value)1 | Minimum Pipe Insulation Required (Thickness in inches or R-value)1 |
| 40–60 | 0.21–0.27 | 75 | Inches | Nonres 0.5 |
Res 0.75 |
Nonres 0.5 |
Res 0.75 |
1.0 | 1.0 | 1.0 |
| 40–60 | 0.21–0.27 | 75 | R-value | Nonres R-3 |
Res R-6 |
Nonres R-3 |
Res R-5 |
R-7 | R-6 | R-5 |
| Below 40 | 0.20–0.26 | 50 | Inches | 1.0 | 1.0 | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 |
| Below 40 | 0.20–0.26 | 50 | R-value | R-8.5 | R-8.5 | R-14 | R-14 | R-12 | R-10 | R-9 |
- These thicknesses are based on energy efficiency considerations only. Issues such as water vapor permeability or surface condensation sometimes require vapor retarders or additional insulation.
openings greater than 1 /4 inch, the combination of mastic and either mesh or tape shall be used.
Portions of supply-air and return-air ducts conveying heated or cooled air located in one or more of the following spaces shall be insulated to a minimum installed level of R-8:
Outdoors; or
In a space between the roof and an insulated ceiling; or
In a space directly under a roof with fixed vents or openings to the outside or unconditioned spaces; or
In an unconditioned crawlspace; or
In other unconditioned spaces. Portions of supply-air ducts that are not in one of these spaces, including ducts buried in concrete slab, shall be insulated to a minimum installed level of R-4.2 or be enclosed in directly conditioned space.
(b) Duct and plenum materials.
- Factory-fabricated duct systems. A. All factory-fabricated duct systems shall comply
with UL 181 for ducts and closure systems, includ
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