Section 120.3
California Energy Code (Title 24, Part 6) · 2019 edition · updated 2026-09-12 · California
REQUIREMENTS FOR PIPE INSULATION
Nonresidential, high-rise residential, and hotel/motel build - ings 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
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.
70 2019 CALIFORNIA ENERGY CODE
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100735044
NONRESIDENTIAL, HIGH-RISE RESIDENTIAL 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 |
| 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) | ||||
| < 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 thickness are based on energy efficiency considerations only. Issues such as water vapor permeability or surface condensation sometimes require vapor retarders or additional insulation.
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.
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