What minimum insulation R‑values or heat-loss limits apply to unfired storage tanks?

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

• § 207.3.2 High relevance — show source text

  A6.207.3.2 Efficiency. Equipment shall meet the applicable requirements of the Appliance Efficiency Regulations as required by Section A6.210.1, subject to the following:

  1. If more than one standard is listed in the Appliance Efficiency Regulations, the equipment shall meet all the standards listed; and
  2. If more than one test method is listed in the Appliance Efficiency Regulations, the equipment shall comply with the applicable standard when tested with each test method; and
  3. Where equipment can serve more than one function, such as both heating and cooling or both space heating and water heating, it shall comply with all the requirements applicable to each function; and
  4. Where a requirement is for equipment rated at its “maximum rated capacity” or “minimum rated capacity,” the capacity shall be as provided for and allowed by the controls, during steady-state operation.

  A6.207.3.3 Installation. Any service water-heating system or equipment may be installed only if the system or equipment complies with all of the applicable requirements of this subsection for the system or equipment.

  A6.207.3.3.1 Outlet temperature controls. On systems that have a total capacity greater than 167,000 Btu/hr, outlets that require higher than service water temperatures as listed in the ASHRAE Handbook, Applications Volume, shall have separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature.

  A6.207.3.3.2 Temperature controls for public lavatories. The controls shall limit the outlet temperature to 110°F.

  A6.207.3.3.3 Insulation. Unfired service water heater storage tanks and backup tanks for solar water-heating systems shall have:

  1. External insulation with an installed R -value of at least R-12; or

  2. Internal and external insulation with a combined R -value of at least R-16; or

  3. The heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot.

  A6.207.3.3.4 Service water heaters in state buildings. Any newly constructed building constructed by the State shall derive its service water heating from a system that provides at least 60 percent of the energy needed for service water heating from site solar energy or recovered energy.

  Exception: Buildings for which the state architect determines that service water heating from site solar energy or recovered energy is economically or physically infeasible.

  A6.207.4 Natural gas central furnaces, cooking equipment and pool and spa heaters: Pilot lights prohibited.

  Any natural gas system or equipment listed below may be installed only if it does not have a continuously burning pilot light:

  1. Fan-type central furnaces.

  2. Household cooking appliances. Exception: Household cooking appliances without an electrical supply voltage connection and in which each pilot consumes less than 150 Btu/hr.

  3. Pool heaters.

  4. Spa heaters.

  A6.207.5 Controls for space-conditioning systems. Space- conditioning systems shall be installed with controls that comply with the applicable requirements of Subsections A6.207.5.1 through A6.207.5.5.

  A6.207.5.1 Thermostatic controls for each zone. The supply of heating and cooling energy to each space-conditioning zone or dwelling unit shall be controlled by an individual thermostatic control that responds to temperature within the zone and that meets the applicable requirements of Section A6.207.5.2.

• § 6.5 High relevance — show source text

  2. Internal and external insulation with a combined R -value of at least R-16; or

  3. The heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot.

  A6.207.3.3.4 Service water heaters in state buildings. Any newly constructed building constructed by the State shall derive its service water heating from a system that provides at least 60 percent of the energy needed for service water heating from site solar energy or recovered energy.

  Exception: Buildings for which the state architect determines that service water heating from site solar energy or recovered energy is economically or physically infeasible.

  A6.207.4 Natural gas central furnaces, cooking equipment and pool and spa heaters: Pilot lights prohibited.

  Any natural gas system or equipment listed below may be installed only if it does not have a continuously burning pilot light:

  1. Fan-type central furnaces.

  2. Household cooking appliances. Exception: Household cooking appliances without an electrical supply voltage connection and in which each pilot consumes less than 150 Btu/hr.

  3. Pool heaters.

  4. Spa heaters.

  A6.207.5 Controls for space-conditioning systems. Space- conditioning systems shall be installed with controls that comply with the applicable requirements of Subsections A6.207.5.1 through A6.207.5.5.

  A6.207.5.1 Thermostatic controls for each zone. The supply of heating and cooling energy to each space-conditioning zone or dwelling unit shall be controlled by an individual thermostatic control that responds to temperature within the zone and that meets the applicable requirements of Section A6.207.5.2.

  Exception: An independent perimeter heating or cooling system may serve more than one zone without individual thermostatic controls if:

  1. All zones are also served by an interior cooling system;
  2. The perimeter system is designed solely to offset envelope heat losses or gains;

  APPENDIX A6.1-20 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

  APPENDIX A6.1 — VOLUNTARY STANDARDS FOR HEALTH FACILITIES [OSHPD 1, 2 & 4]

  3. The perimeter system has at least one thermostatic control for each building orientation of 50 feet or more; and
  4. The perimeter system is controlled by at least one thermostat located in one of the zones served by the system.

  A6.207.5.2 Criteria for zonal thermostatic controls. The individual thermostatic controls required by Section A6.207.5.1 shall meet the following requirements as applicable:

  1. Where used to control comfort heating, the thermostatic controls shall be capable of being set, locally or remotely, down to 55°F or lower.

  2. Where used to control comfort cooling, the thermostatic controls shall be capable of being set, locally or remotely, up to 85°F or higher.

  3. Where used to control both comfort heating and comfort cooling, the thermostatic controls shall meet Items 1 and 2 and shall be capable of providing a temperature range or dead band of at least 5°F within which the supply of heating and cooling energy to the zone is shut off or reduced to a minimum. Exception: Systems with thermostats that require manual changeover between heating and cooling modes.
• § 110.3 High relevance — show source text

  1. Outlet temperature controls. On systems that have a total capacity greater than 167,000 Btu/hr, outlets that require higher than service water temperatures as listed in the ASHRAE Handbook, Applications Volume, shall have separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature. Exception to Section 110.3(c)1: Systems covered by California Plumbing Code Section 613.0 shall instead follow the requirements of that section.
  2. Controls for hot water distribution systems. Service hot water systems with circulating pumps or with electrical heat trace systems shall be capable of automatically turning off the system. Exception to Section 110.3(c)2: Systems serving healthcare facilities.
  3. Insulation. Unfired service water heater storage tanks and backup tanks for solar water-heating systems shall have: A. External insulation with an installed R -value of at least R-3.5; or

  B. Internal and external insulation with a combined R -value of at least R-16; or

  C. The heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot. 4. Water heating recirculation loops serving multiple dwelling units, high-rise residential, hotel/motel, and nonresiden- tial occupancies. A water heating recirculation loop is a type of hot water distribution system that reduces the time needed to deliver hot water to fixtures that are distant from the water heater, boiler or other water heating equipment. The recirculation loop is comprised of a supply portion, connected to branches that serve multiple dwelling units, guest rooms, or fixtures and a return portion that completes the loop back to the water heating equipment. A water heating recirculation loop shall meet the following requirements: A. Air release valve or vertical pump installation. An automatic air release valve shall be installed on the recirculation loop piping on the inlet side of the recirculation pump and no more than 4 feet from the pump. This valve shall be mounted on top of a vertical riser at least 12 inches in length and shall be accessible for replacement and repair. Alternatively, the pump shall be installed on a vertical section of the return line. B. Recirculation loop backflow prevention. A check valve or similar device shall be located between the recirculation pump and the water heating equipment to prevent water from flowing backwards though the recirculation loop. C. Equipment for pump priming. A hose bibb shall be installed between the pump and the water heating equipment. An isolation valve shall be installed between the hose bibb and the water heating equipment. This hose bibb is used for bleeding air out of the pump after pump replacement. D. Pump isolation valves. Isolation valves shall be installed on both sides of the pump. These valves may be part of the flange that attaches the pump to the pipe. One of the isolation valves may be the same isolation valve as in Item C. E. Cold water supply and recirculation loop connection to hot water storage tank. Storage water heaters and boilers shall be plumbed in accordance with the manufacturer’s specifications The cold water piping and the recirculation loop piping shall not be connected to the hot water storage tank drain port. F. Cold water supply backflow prevention. A check valve shall be installed on the cold water supply line between the hot water system and the next closest tee on the cold water supply line.

• § 1.9 High relevance — show source text

  9| |7 to 8|R-1.9|R-1.9|R-1.9|

  Notes: 1 Insulation R-values, measured in [°F•h•ft 2 /(Btu•in)] [(m•K)/W], are for the insulation as installed and do not include film resistance. The required minimum thicknesses do not consider water vapor transmission and possible surface condensation. Where portions of the building envelope are used as a plenum enclosure, building envelope insulation shall be as required by the most restrictive condition of Section E 503.4.7.1 or ASHRAE 90.1, depending on whether the plenum is located in the roof, wall, or floor. Insulation resistance measured on a horizontal plane in accordance with ASTM C518 at a mean temperature of 75°F (24°C) at the installed thickness. 2 Includes attics above insulated ceilings, parking garages and crawl spaces. 3 Includes return air plenums, with or without exposed roofs above. 4 Return ducts in this duct location do not require insulation.

  TABLE E 503.7.3(1) MINIMUM PIPE INSULATION THICKNESS FOR HEATING AND HOT WATER SYSTEMS [1, 2, 3, 4, 5]

  (STEAM, STEAM CONDENSATE, HOT WATER HEATING, AND DOMESTIC WATER SYSTEMS)

  [ASHRAE 90.1: TABLE 6.8.3-1]

  FLUID OPERATING TEMPERATURE RANGE (F°) AND USAGE	INSULATION CONDUCTIVITY	Col3	NOMINAL PIPE SIZE OR TUBE SIZE (inches)	Col5	Col6	Col7	Col8
  FLUID OPERATING TEMPERATURE RANGE (F°) AND USAGE	CONDUCTIVITY Btu•inch/(h•ft2•°F)	MEAN RATING TEMPERATURE °F	<1	1 to <11_/_2	11_/_2 to <4	4 to <8	≥8
  FLUID OPERATING TEMPERATURE RANGE (F°) AND USAGE	CONDUCTIVITY Btu•inch/(h•ft2•°F)	MEAN RATING TEMPERATURE °F	INSULATION THICKNESS (inches)	INSULATION THICKNESS (inches)	INSULATION THICKNESS (inches)	INSULATION THICKNESS (inches)	INSULATION THICKNESS (inches)
  >350	0.32 to 0.34	250	4.5	5.0	5.0	5.0	5.0
  251 to 350	0.29 to 0.32	200	3.0	4.0	4.5	4.5	4.5
  201 to 250	0.27 to 0.30	150	2.5	2.5	2.5	3.0	3.0
  141 to 200	0.25 to 0.29	125	1.5	1.5	2.0	2.0	2.0
  105 to 140	0.22 to 0.28	100	1.

• § 90.1 High relevance — show source text

  [ASHRAE 90.1: TABLE 6.8.3-2]

  FLUID OPERATING TEMPERATURE RANGE (°F) AND USAGE	INSULATION CONDUCTIVITY	Col3	NOMINAL PIPE SIZE OR TUBE SIZE (inches)	Col5	Col6	Col7	Col8
  FLUID OPERATING TEMPERATURE RANGE (°F) AND USAGE	CONDUCTIVITY Btu•inch/(h•f2•°F)	MEAN RATING TEMPERATURE °F	<1	1 to <11_/_2	11_/_2 to <4	4 to <8	≥8
  FLUID OPERATING TEMPERATURE RANGE (°F) AND USAGE	CONDUCTIVITY Btu•inch/(h•f2•°F)	MEAN RATING TEMPERATURE °F	INSULATION THICKNESS (inches)	INSULATION THICKNESS (inches)	INSULATION THICKNESS (inches)	INSULATION THICKNESS (inches)	INSULATION THICKNESS (inches)
  40 to 60	021 to 0.27	75	0.5	0.5	1.0	1.0	1.0
  <40	0.20 to 0.26	50	0.5	1.0	1.0	1.0	1.5

  For SI units: °C = (°F-32)/1.8, 1 inch = 25 mm, 1 British thermal unit inch per hour square foot degree Fahrenheit = [0.1 W/(m•k)]

  Notes: 1 For insulation outside the stated conductivity range, the minimum thickness ( T ) shall be determined as follows: T = r {(1 + t/r ) [K/k ] – 1}

  Where:

  T = minimum insulation thickness (inches). r = actual outside radius of pipe (inches). t = insulation thickness listed in this table for applicable fluid temperature and pipe size. K = conductivity of alternate material at mean rating temperature indicated for the applicable fluid temperature [Btu • inch/(h • ft [2] • °F)] [W/(m•K)]. k = the upper value of the conductivity range listed in this table for the applicable fluid temperature. 2 These thicknesses are based on energy efficiency considerations only. Issues such as water, vapor permeability, or surface condensation require vapor retarders or additional insulation. 3 For direct-buried cooling system piping, insulation is not required. 4 Table E 503.7.3(2) is based on steel pipe. Nonmetallic pipes schedule 80 thickness or less shall use the table values. For other nonmetallic pipes having thermal resistance more than that of steel pipe, reduced insulation thicknesses are permitted where documentation is provided showing that the pipe with the proposed insulation has no more heat transfer per foot (mm) than a steel pipe of the same size with the insulation thickness shown in Table E 503.7.3(2).

• § 0.34 High relevance — show source text

  32 to 0.34|250|4.5|5.0|5.0|5.0|5.0| |251 to 350|0.29 to 0.32|200|3.0|4.0|4.5|4.5|4.5| |201 to 250|0.27 to 0.30|150|2.5|2.5|2.5|3.0|3.0| |141 to 200|0.25 to 0.29|125|1.5|1.5|2.0|2.0|2.0| |105 to 140|0.22 to 0.28|100|1.0|1.0|1.5|1.5|1.5|

  For SI units: °C=(°F-32)/1.8, 1 inch = 25 mm, 1 British thermal unit inch per hour square foot degree Fahrenheit = [0.1 W/(m•K)]

  Notes: 1 For insulation outside the stated conductivity range, the minimum thickness ( T ) shall be determined as follows: T = r {(1 + t / r ) [K] [/] [k ] – 1}

  Where:

  T = minimum insulation thickness (inches). r = actual outside radius of pipe (inches). t = insulation thickness listed in this table for applicable fluid temperature and pipe size. K = conductivity of alternate material at mean rating temperature indicated for the applicable fluid temperature [Btu•in/(h•ft [2] - °F)] [W/(m•K)]. k = the upper value of the conductivity range listed in this table for the applicable fluid temperature. 2 These thicknesses are on energy efficiency considerations only. Additional insulation is sometimes required relative to safety issues/surface temperature. 3 For piping smaller than 1 1 ⁄ 2 inches (40 mm) or less and located in partitions within conditioned spaces, reduction of these thicknesses by 1 inch (25.4 mm) shall be permitted (before thickness adjustment required in footnote 1) but not to thicknesses below 1 inch (25.4 mm). 4 For direct-buried heating and hot water system piping, reduction of these thicknesses by 1 1 ⁄ 2 inch (40 mm) shall be permitted (before thickness adjustment required in footnote 1) but not to thicknesses below 1 inch (25.4 mm). 5 Table E 503.7.3(1) is based on steel pipe. Nonmetallic pipes schedule 80 thickness or less shall use the table values. For other nonmetallic pipes having thermal resistance more than that of steel pipe, reduced insulation thicknesses are permitted where documentation is provided showing that the pipe with the proposed insulation has no more heat transfer per foot (mm) than a steel pipe of the same size with the insulation thickness shown in Table E 503.7.3(1).

  474 2025 CALIFORNIA MECHANICAL CODE

  ), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.

  APPENDIX E

  TABLE E 503.7.3(2) MINIMUM PIPE INSULATION THICKNESS FOR COOLING SYSTEMS (CHILLED WATER, BRINE, AND REFRIGERANT) [1,2,3,4 ]

  [ASHRAE 90.1: TABLE 6.8.3-2]

• § 0.46 High relevance — show source text

  46| |Operable Window (Max_U_-factor)|0.46|0.46|0.46|0.46|0.46|0.46|0.46|0.46|0.46|0.46|0.46|0.46|0.46|0.46|0.46|0.46| |Operable Window (Max RSHGC)|0.22|0.22|0.22|0.22|0.22|0.22|0.22|0.22|0.22|0.22|0.22|0.22|0.22|0.22|0.22|0.22| |Operable Window (Min VT)|0.32|0.32|0.32|0.32|0.32|0.32|0.32|0.32|0.32|0.32|0.32|0.32|0.32|0.32|0.32|0.32| |Glazed Doors (Max_U_-factor)|0.45|0.45|0.45|0.45|0.45|0.45|0.45|0.45|0.45|0.45|0.45|0.45|0.45|0.45|0.45|0.45| |Glazed Doors (Max RSHGC)|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23|0.23| |Glazed Doors (Min VT)|0.17|0.17|0.17|0.17|0.17|0.17|0.17|0.17|0.17|0.17|0.17|0.17|0.17|0.17|0.17|0.17| |Fenestration (Max WWR %)|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|40%|

  FENESTRATION – SKYLIGHTS (all climate zones) (area-weighted performance rating)	GLASS CURB MOUNTED	GLASS DECK MOUNTED	PLASTIC CURB MOUNTED	TUBULAR DAYLIGHTING DEVICES (TDDS)
  Max U-factor	0.58	0.46	0.88	0.88
  Max SHGC	0.25	0.25	NR	NR
  Min VT (Min VTannual for TDDs)	0.49	0.49	0.64	0.38
  Maximum SRR %	5%	5%	5%	5%
  Note: 1. As defined in Section 100.1, light mass walls are walls with a heat capacity of at least 7.0 Btu/ft2-°F and less than 15.0 Btu/ft2-°F. Heavy mass walls are walls with a heat capac- ity of at least 15.0 Btu/ft2-°F.	Note: 1.

• § 110.3 High relevance — show source text

  SECTION 110.3—MANDATORY REQUIREMENTS FOR SERVICE WATER-HEATING SYSTEMS AND EQUIPMENT

  (a) Certification by manufacturers. Any service water- heating system or equipment may be installed only if the manufacturer has certified that the system or equipment complies with all of the requirements of this subsection for that system or equipment.

  1. Temperature controls for service water-heating systems. Service water-heating systems shall be equipped with automatic temperature controls capable of adjustment from the lowest to the highest acceptable temperature settings for the intended use as listed in Table 3, Chapter 50 of the ASHRAE Handbook, HVAC Applications Volume or Table 613.1 of the Cali- fornia Plumbing Code for healthcare facilities. Exception to Section 110.3(a)1: Residential occupancies.

  (b) Efficiency. Equipment shall meet the applicable requirements of the Appliance Efficiency Regulations as required by Section 110.1, subject to the following:

  1. If more than one standard is listed in the Appliance Efficiency Regulations, the equipment shall meet all the standards listed; and

  2. If more than one test method is listed in the Appliance Efficiency Regulations, the equipment shall comply with the applicable standard when tested with each test method; and

  3. Where equipment can serve more than one function, such as both heating and cooling, or both space heating and water heating, it shall comply with all the requirements applicable to each function; and

  4. Where a requirement is for equipment rated at its “maximum rated capacity” or “minimum rated capacity,” the capacity shall be as provided for and allowed by the controls, during steady-state operation.

  (c) Installation. Any service water-heating system or equipment may be installed only if the system or equipment complies with all of the applicable requirements of this subsection for the system or equipment.

  1. Outlet temperature controls. On systems that have a total capacity greater than 167,000 Btu/hr, outlets that require higher than service water temperatures as listed in the ASHRAE Handbook, Applications Volume, shall have separate remote heaters, heat exchangers or boosters to supply the outlet with the higher temperature. Exception to Section 110.3(c)1: Systems covered by California Plumbing Code Section 613.0 shall instead follow the requirements of that section.
  2. Controls for hot water distribution systems. Service hot water systems with circulating pumps or with electrical heat trace systems shall be capable of automatically turning off the system. Exception to Section 110.3(c)2: Systems serving healthcare facilities.
  3. Insulation. Unfired service water heater storage tanks and backup tanks for solar water-heating systems shall have: A. External insulation with an installed R -value of at least R-3.5; or

  B. Internal and external insulation with a combined R -value of at least R-16; or

  C. The heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot. 4. Water heating recirculation loops serving multiple dwelling units, high-rise residential, hotel/motel, and nonresiden- tial occupancies. A water heating recirculation loop is a type of hot water distribution system that reduces the time needed to deliver hot water to fixtures that are distant from the water heater, boiler or other water heating equipment. The recirculation loop is comprised of a supply portion, connected to branches that serve multiple dwelling units, guest rooms, or fixtures and a return portion that completes the loop back to the water heating equipment.

• § 90.1 High relevance — show source text

  [ASHRAE 90.1: TABLE 7.8]

  EQUIPMENT TYPE	SIZE CATEGORY (INPUT)	SUBCATEGORY OR RATING CONDITION	PERFORMANCE REQUIRED1	TEST PROCEDURE2,3
  Pool heaters, gas	All	—	82%Et for commercial pool heaters and for applications out- side U.S. For U.S. applications, see foot- note (7).	Appendix P of 10 CFR 430
  Heat pump pool heaters	All	50°F db 44.2°F wb Outdoor air 80.0°F entering water	4.0 COP	Appendix P of 10 CFR 430
  Unfired storage tanks	All	—	R-12.5	(none)

  For SI units: 1 gallon = 3.785 L, 1000 British thermal units per hour = 0.293 kW, °C = (°F-32)/1.8

  Notes: 1 Thermal efficiency ( Et ) is a minimum requirement, while standby loss (SL) is a maximum requirement. In the SL equation, V is the rated volume in gallons and Q is the nameplate input rate in Btu/h (kW). Vm is the measured volume in the tank in gallons. Standby loss for electric water heaters is in terms of %/h and denoted by the term “S,” and standby loss for gas and oil water heaters is in terms of Btu/h and denoted by the term “SL.” Draw pattern (DP) refers to the water draw profile in the Uniform Energy Factor (UEF) test. UEF and Energy Factor (EF) are minimum requirements. In the UEF standard equations, Vr refers to the rated volume in gallons. 2 ASHRAE 90.1 contains a complete specification, including the year version, of the referenced test procedure. 3 Electric instantaneous water heaters with input capacity >40 946 Btu/h (12 kW) and ≤ 200 000 Btu/h (58.6 kW) must comply with the requirements for the 200 000 Btu/h (58.6 kW) if the water heater either: (a) has a storage volume >2 gallons (7.6 L); (b) is designed to provide outlet hot water at temperatures greater than 180°F (82°C); or (c) uses three phase power. 4 Gas storage water heaters with input capacity >75 000 Btu/h (22 kW) and ≤ 105 000 Btu/h (30.8 kW) must comply with the requirements for the >105 000 Btu/h (30.8 kW) if the water heater either: (a) has a storage volume >120 gallons (454 L); (b) is designed to provide outlet hot water at temperatures greater than 180°F (82.2°C); or (c) uses three-phase power 5 Oil storage water heaters with input capacity >105 000 Btu/h (30.8 kW) and ≤ 140 000 Btu/h (41.0 kW) must comply with the requirements for the >140 000 Btu/h (41.0 kW) if the water heater either (a) has a storage volume >120 gallons (454 L); (b) is designed to provide outlet hot water at temperatures greater than 180°F (82.2°C); or (c) uses three-phase power 6 Refer to Section L 503.4.3 for additional requirements for gas storage and instantaneous water heaters and gas hot-water supply boilers.

• § 205.3.4.2 High relevance — show source text

  A6.205.3.4.2 Water heaters. If external insulation is installed on an existing unfired water storage tank or on an existing backup tank for a solar water-heating system, it shall have an R -value of at least R-12 or the heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot.

  A6.205.3.4.3 Ducts. If insulation is installed on an existing space-conditioning duct, it shall comply with Section 605 of the California Mechanical Code (CMC).

  A6.205.3.5 Placement of roof/ceiling insulation. Insulation installed to limit heat loss and gain through the top of conditioned spaces shall comply with the following:

  A6.205.3.5.1 Insulation shall be installed in direct contact with a continuous roof or ceiling which is sealed to limit infiltration and exfiltration as specified in Section A6.205.2, including but not limited to placing insulation either above or below the roof deck or on top of a drywall ceiling; and

  A6.205.3.5.2 When insulation is installed at the roof in nonresidential buildings, fixed vents or openings to the outdoors or to unconditioned spaces shall not be installed and the space between the ceiling and the roof is either directly or indirectly conditioned space and shall not be considered an attic for the purposes of complying with CBC attic ventilation requirements; and

  APPENDIX A6.1-6 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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

  APPENDIX A6.1 — VOLUNTARY STANDARDS FOR HEALTH FACILITIES [OSHPD 1, 2 & 4]

  A6.205.3.5.3 Insulation placed on top of a suspended ceiling with removable ceiling panels shall be deemed to have no affect on envelope heat loss; and

  Exception: When there are conditioned spaces with a combined floor area no greater than 2,000 square feet in an otherwise unconditioned building and when the average height of the space between the ceiling and the roof over these spaces is greater than 12 feet, insulation placed in direct contact with a suspended ceiling with removable ceiling panels shall be an acceptable method of reducing heat loss from a conditioned space and shall be accounted for in heat loss calculations.

  A6.205.3.5.4 Insulation shall be installed below the roofing membrane or layer used to seal the roof from water penetration unless the insulation has a maximum water absorption of 0.3 percent by volume when tested according to ASTM C272.

  Note: Vents, which do not penetrate the roof deck, that are designed for wind resistance for roof membranes are not within the scope of Section A6.205.3.5.2.

  A6.205.3.6 Demising walls in nonresidential buildings. The opaque portions of framed demising walls in nonresidential buildings shall be insulated with an installed R -value of no less than R-13 between framing members.

  A6.205.3.7 Insulation requirements for heated slab floors. Heated slab-on-grade floors shall be insulated according to the requirements in Table A6.205.3-A.

• § 5704.3.6.3 High relevance — show source text

  
  Ordinary
  temperature,
  quick-response
  sprinklers,
  maximum 8
  feet 3 inches
  horizontal
  spacing
  2.
  One line
  sprinklers
  above each
  level of storage
  3.
  Locate in
  longitudinal
  flue space,
  staggered
  vertical
  4.
  Shields
  required where
  multiple-level|1.
  Ordinary
  temperature,
  quick-response
  sprinklers,
  maximum 8
  feet 3 inches
  horizontal
  spacing
  2.
  See 2 above
  3.
  See 3 above
  4.
  See 4 above|Not Applicable
  None for maximum
  6-foot-deep racks| |TABLE 5704.3.6.3(5)—AUTOMATIC SPRINKLER PROTECTION REQUIREMENTS FOR RACK STORAGE OF LIQUIDS IN
  METAL CONTAINERS OF 5-GALLON CAPACITY OR LESS WITH OR WITHOUT CARTONS ON CONVENTIONAL WOOD PALLETSa|IN-RACK SPRINKLER ARRANGEMENT AND DEMAND|Maximum
  spacing|Maximum
  spacing|80 ft2/head|100 ft2/head|100 ft2/head| |TABLE 5704.3.6.3(5)—AUTOMATIC SPRINKLER PROTECTION REQUIREMENTS FOR RACK STORAGE OF LIQUIDS IN
  METAL CONTAINERS OF 5-GALLON CAPACITY OR LESS WITH OR WITHOUT CARTONS ON CONVENTIONAL WOOD PALLETSa|CEILING SPRINKLER DESIGN AND
  DEMAND|Area
  (square feet)|Ordinary
  temperature
  sprinklers|5,000|Not
  Applicable|Not
  Applicable| |TABLE 5704.3.6.3(5)—AUTOMATIC SPRINKLER PROTECTION REQUIREMENTS FOR RACK STORAGE OF LIQUIDS IN
  METAL CONTAINERS OF 5-GALLON CAPACITY OR LESS WITH OR WITHOUT CARTONS ON CONVENTIONAL WOOD PALLETSa|CEILING SPRINKLER DESIGN AND
  DEMAND|Area
  (square feet)|High-
  temperature
  sprinklers|3,000|2,000b|2,000d| |TABLE 5704.3.6.3(5)—AUTOMATIC SPRINKLER PROTECTION REQUIREMENTS FOR RACK STORAGE OF LIQUIDS IN
  METAL CONTAINERS OF 5-GALLON CAPACITY OR LESS WITH OR WITHOUT CARTONS ON CONVENTIONAL WOOD PALLETSa|CEILING SPRINKLER DESIGN AND
  DEMAND|Density
  (gpm/ft2)|Density
  (gpm/ft2)|0.40|0.55|0.55c| |**TABLE 5704.3.6.

• § 205.3.3 High relevance — show source text

  1. It is installed in exterior side walls; and

  2. A four-mil-thick plastic polyethylene vapor barrier or equivalent plastic sheathing vapor barrier is installed between the urea formaldehyde foam insulation and the interior space in all applications.

  A6.205.3.3 Flame spread rating. All insulating material shall be installed in compliance with the flame spread rating and smoke density requirements of the Title 24, Part 2, California Building Code.

  A6.205.3.4 Installation of insulation in existing buildings. Insulation installed in an existing attic or on an existing duct or water heater, shall comply with the applicable requirements of Subsections A6.205.3.4.1, A6.205.3.4.2 and A6.205.3.4.3 below. If a contractor installs the insulation, the contractor shall certify to the customer, in writing, that the insulation meets the applicable requirements of Subsections A6.205.3.4.1, A6.205.3.4.2 and A6.205.3.4.3 below.

  A6.205.3.4.1 Attics. If insulation is installed in the existing attic of a low-rise residential building, the R-value of the total amount of insulation (after addition of insulation to the amount, if any, already in the attic) shall be at least R-38 in climate zones 1 and 16; and R-30 in all other climate zones.

  Exception: Where the accessible space in the attic is not large enough to accommodate the required R-value, the entire accessible space shall be filled with insulation provided such installation does not violate Section 1203.2 of Title 24, Part 2, California Building Code.

  A6.205.3.4.2 Water heaters. If external insulation is installed on an existing unfired water storage tank or on an existing backup tank for a solar water-heating system, it shall have an R -value of at least R-12 or the heat loss of the tank surface based on an 80°F water-air temperature difference shall be less than 6.5 Btu per hour per square foot.

  A6.205.3.4.3 Ducts. If insulation is installed on an existing space-conditioning duct, it shall comply with Section 605 of the California Mechanical Code (CMC).

  A6.205.3.5 Placement of roof/ceiling insulation. Insulation installed to limit heat loss and gain through the top of conditioned spaces shall comply with the following:

  A6.205.3.5.1 Insulation shall be installed in direct contact with a continuous roof or ceiling which is sealed to limit infiltration and exfiltration as specified in Section A6.205.2, including but not limited to placing insulation either above or below the roof deck or on top of a drywall ceiling; and

  A6.205.3.5.2 When insulation is installed at the roof in nonresidential buildings, fixed vents or openings to the outdoors or to unconditioned spaces shall not be installed and the space between the ceiling and the roof is either directly or indirectly conditioned space and shall not be considered an attic for the purposes of complying with CBC attic ventilation requirements; and

  APPENDIX A6.1-6 2025 CALIFORNIA GREEN BUILDING STANDARDS CODE

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