Design & Sizing

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

• CMC § 101.0 Medium relevance — show source text

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  APPENDIX F

  SIZING OF VENTING SYSTEMS AND OUTDOOR COMBUSTION

  AND VENTILATION OPENING DESIGN

  The provisions contained in this appendix are not mandatory unless specifically adopted by a state agency, or referenced in the adopting ordinance.

  F 101.0 General.

  F 101.1 Applicability. This appendix provides general guidelines for sizing venting systems serving appliances equipped with draft hoods, Category I appliances, and appliances listed for use with Type B vents.

  Table 803.1.2(1) is used when sizing a Type B double-wall gas vent connected directly to the appliance.

  Note: The appliance can be either Category I draft hood-equipped or fanassisted type.

  FIGURE F 101.2(1) TYPE B DOUBLE-WALL VENT SYSTEM SERVING A SINGLE APPLIANCE WITH A TYPE B DOUBLE-WALL VENT

  [NFPA 54: FIGURE F.1(a)]

  Table 803.1.2(2) is used when sizing a single-wall metal vent connector attached to a Type B double-wall gas vent.

  Note: The appliance can be either Category I draft hood-equipped or fanassisted type.

  FIGURE F 101.2(2) TYPE B DOUBLE-WALL VENT SYSTEM SERVING A SINGLE APPLIANCE WITH A SINGLE-WALL METAL VENT CONNECTOR

  [NFPA 54: FIGURE F.1(b)]

  F 101.2 Examples Using Single Appliance Venting Tables. See Figure F 101.2(1) through Figure F 101.2(14).

  [NFPA 54:F.1]

  Table 803.1.2(3) is used when sizing a Type B double-wall gas vent connector attached to a tile-lined masonry chimney.

  Notes:

  1. A is the equivalent cross-sectional area of the tile liner.
  2. The appliance can be either Category I draft hood-equipped or fanassisted type.

  FIGURE F 101.2(3) VENT SYSTEM SERVING A SINGLE APPLIANCE WITH A MASONRY CHIMNEY AND A TYPE B DOUBLE-WALL VENT CONNECTOR

  [NFPA 54: FIGURE F.1(c)]

  Table 803.1.2(4) is used when sizing a single-wall vent connector attached to a tile-lined masonry chimney.

  Notes:

  1. A is the equivalent cross-sectional area of the tile liner.
  2. The appliance can be either Category I draft hood-equipped or fanassisted type.

  FIGURE F 101.2(4) VENT SYSTEM SERVING A SINGLE APPLIANCE USING A MASONRY CHIMNEY AND A SINGLE-WALL METAL VENT CONNECTOR

  [NFPA 54: FIGURE F.1(d)]

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  2025 CALIFORNIA MECHANICAL CODE 535

• CMC § 1.11.0. Medium relevance — show source text

  Adopting Agency	BSC	BSC- CG	SFM	HCD	Col6	Col7	DSA	Col9	Col10	OSHPD	Col12	Col13	Col14	Col15	Col16	Col17	BSCC	DPH	AGR	DWR	CEC	CA	SL	SLC
  Adopting Agency	BSC	BSC- CG	SFM	1	2	1-AC	AC	** SS**	** SS/CC**	1	1R	2	3	4	5	6	6	6	6	6	6	6	6	6
  Adopt Entire Chapter
  Adopt Entire Chapter as amended (amended sections listed below)
  Adopt only those sections that are listed below
  Chapter/Section

  This state agency does not adopt sections identified with the following symbol: † The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.

  2025 CALIFORNIA MECHANICAL CODE 533

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  534 2025 CALIFORNIA MECHANICAL CODE

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  APPENDIX F

  SIZING OF VENTING SYSTEMS AND OUTDOOR COMBUSTION

  AND VENTILATION OPENING DESIGN

  The provisions contained in this appendix are not mandatory unless specifically adopted by a state agency, or referenced in the adopting ordinance.

  F 101.0 General.

  F 101.1 Applicability. This appendix provides general guidelines for sizing venting systems serving appliances equipped with draft hoods, Category I appliances, and appliances listed for use with Type B vents.

  Table 803.1.2(1) is used when sizing a Type B double-wall gas vent connected directly to the appliance.

  Note: The appliance can be either Category I draft hood-equipped or fanassisted type.

  FIGURE F 101.2(1) TYPE B DOUBLE-WALL VENT SYSTEM SERVING A SINGLE APPLIANCE WITH A TYPE B DOUBLE-WALL VENT

  [NFPA 54: FIGURE F.1(a)]

  Table 803.1.2(2) is used when sizing a single-wall metal vent connector attached to a Type B double-wall gas vent.

  Note: The appliance can be either Category I draft hood-equipped or fanassisted type.

• CMC § 5.3.2.3 Medium relevance — show source text

  The total connected hourly load shall be used as the basis for piping sizing, assuming all appliances are operating at full capacity simultaneously. Exception: Sizing shall be permitted to be based upon established load diversity factors. [NFPA 54:5.3.2.3] 1308.3.2 Sizing Methods. Gas piping shall be sized in accordance with one of the following: (1) Pipe sizing tables or sizing equations in this chapter.

  (2) Sizing tables included in a listed piping system manufacturer’s installation instructions.

  (3) Engineering methods. [NFPA 54:5.3.3] 1308.3.3 Allowable Pressure Drop. The design pressure loss in a piping system from the point of delivery to the inlet connection of all appliances served shall be such that the supply pressure at each appliance inlet is greater than or equal to the minimum pressure required by the appliance. [NFPA 54:5.3.4] 1308.4 Acceptable Piping Materials and Joining Methods. Materials used for piping systems shall comply with the requirements of Section 1308.4.1 through Section 1308.4.4.2.3. {NFPA 54:5.5.1.1} 1308.4.1 Used Materials. Pipe, fittings, valves, or other materials shall not be used again unless they are free of foreign materials and have been ascertained to be adequate for the service intended. [NFPA 54:5.5.1.2] 1308.4.2 Metallic Pipe. Metallic pipe shall be in accordance with Section 1308.4.2.1 through Section 1308.4.2.4.

  1308.4.2.1 Cast Iron. Cast-iron pipe shall not be used. [NFPA 54:5.5.2.1] 1308.4.2.2 Steel, Stainless Steel, and Wrought-Iron. Steel, stainless steel, and wroughtiron pipe shall be at least Schedule 40 and shall comply with the dimensional standards of ASME B36.10M and one of the following: (1) ASTM A53 (2) ASTM A106 (3) ASTM A312 {NFPA 54:5.5.2.2}

  TABLE 1308.3.1

  APPROXIMATE GAS INPUT FOR TYPICAL APPLIANCES

  [NFPA 54: TABLE A.5.3.2.1]

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  2025 CALIFORNIA MECHANICAL CODE 277

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  FUEL GAS PIPING

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  1308.4.3 Metallic Tubing. Tubing shall not be used with gases corrosive to the tubing material. [NFPA 54:5.5.3.1] 1308.4.3.1 Steel Tubing. Steel tubing shall comply with ASTM A254. [NFPA 54:5.5.3.2] **1308.4.3.2 Stainless Steel Tubing.

• CMC § 160.3 Medium relevance — show source text

  Mass radiant floor slab systems shall incorporate floor temperature onto the optimum start algorithm. Exception to Section 160.3(a)2J: Systems that must operate continuously.

  (b) Dwelling unit space-conditioning and air distribution systems.

  1. Building cooling and heating loads. Building heating and cooling loads shall be determined using a method based on any one of the following, using cooling and heating loads as two of the criteria for equipment sizing and selection: A. The ASHRAE Handbook, Equipment Volume, Applications Volume and Fundamentals Volume; or B. The SMACNA Residential Comfort System Installation Standards Manual; or

  C. The ACCA Manual J.

  Exception to Section 160.3(b)1: Block loads, the total load for all rooms combined that are served by the central equipment, may be used for the purpose of system sizing for additions. NOTE: Heating systems are required to have a minimum heating capacity adequate to meet the minimum requirements of the CBC.

  2. Design conditions . Design conditions shall be determined in accordance with the following: A. For the purpose of sizing the space-conditioning (HVAC) system, the indoor design temperatures shall be 68°F for heating and 75°F for cooling. B. Outdoor design conditions shall be selected from one of the following: i. Reference Joint Appendix JA2, which is based on data from the ASHRAE Climatic Data for Region X; or ii. The ASHRAE Handbook Fundamentals Volume; or

  iii. The ACCA Manual J.

  C. The outdoor design temperatures for heating shall be no lower than the 99.0 percent Heating Dry Bulb or the Heating Winter Median of Extremes values.

  D. The outdoor design temperatures for cooling shall be no greater than the 1.0 percent Cooling Dry Bulb and Mean Coincident Wet Bulb values.

  214 2025 CALIFORNIA ENERGY CODE

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  MULTIFAMILY BUILDINGS—MANDATORY REQUIREMENTS

  3. Outdoor condensing units . A. Clearances. Installed air conditioner and heat pump outdoor condensing units shall have a clearance of at least 5 feet (1.5 meters) from the outlet of any dryer vent. B. Liquid line drier. Installed air conditioner and heat pump systems shall be equipped with liquid line filter driers if required, as specified by manufacturer’s instructions.
  4. Central forced-air heating furnaces . A. Temperature rise . Central forced-air heating furnace installations shall be configured to operate in conformance with the furnace manufacturer's maximum inlet-to-outlet temperature rise specifications.
  5. Air-distribution and ventilation system ducts, plenums and fans. A. CMC compliance.

  i. All air-distribution system ducts and plenums, including, but not limited to, mechanical closets and air-handler boxes, shall meet the requirements of the CMC Sections 601.0, 602.0, 603.0, 604.0 and 605.0 and ANSI/SMACNA006-2006 HVAC Duct Construction Standards Metal and Flexible 3rd Edition, incorporated herein by reference. ii. Portions of supply-air and return-air ducts and plenums of a space heating or cooling system shall be insulated in accordance with either Subsection a or b below:

  a. Ducts shall have a minimum installed level of R-6.0, or

• CMC § 140.4 Medium relevance — show source text

  If chilled water produced by an AWHP is used for space cooling, then the heat recovery system shall comply with Section 140.4(s), and iii. Supplemental heating shall be provided by an electric resistance boiler with a capacity of not greater than 50 percent of the design space-heating hot water loop heating capacity. D. Indoor fans. Indoor fans used to comply with the requirements of Section 140.4(a)3Ai or 140.4(a)3Aii shall have a maximum fan power of 0.35 W/cfm at design airflow, shall have not less than three speeds and shall turn off when there is no demand for heating or cooling in the space. At 66 percent airflow the power draw shall be no more than 51 percent of the fan power at full fan speed, and at 33 percent airflow the power draw shall be no more than 12 percent of the fan power at full fan speed. E. DOAS. DOAS used to comply with the requirements of Section 140.4(a)3Ai or 140.4(a)3Aii shall comply with Section 140.4(p), be equipped with a heat recovery system in compliance with Section 140.4(q) and have a maximum fan power of 0.77 W/cfm at design airflow. DOAS units that provide active heating or cooling shall meet one of the following requirements: i. For hydronic heating or cooling: a. DOAS heating coils shall be hydronic heating coils utilizing the AWHP space-heating hot water loop. b. DOAS cooling coils shall be hydronic cooling coils utilizing space-cooling chilled water loop. ii. Other heating or cooling shall be provided by a heat pump. Electric resistance heating shall not be used. F. Parallel fan-powered boxes used to comply with Section 140.4(a)3Aiii shall use recirculated zone or plenum air shall be used in heating mode. Fans shall cycle on only when there is a demand for heating and shall have a maximum fan power of 0.3 W/cfm at design airflow. Terminal units providing ventilation air shall be set to no greater than the minimum ventilation rate when the zone is in deadband or in heating mode.

  (b) Calculations. In making equipment sizing calculations under Subsection (a), all of the following rules shall apply:

  1. Heating and cooling loads. Heating and cooling system design loads shall be determined in accordance with the procedures described in Subsection A or B below:

  A. For systems serving hotel/motel buildings, and nonresidential buildings other than healthcare facilities, the method in the 2017 ASHRAE Handbook, Fundamentals shall be used or as specified in a method approved by the Commission. B. For system serving healthcare facilities the method in the California Mechanical Code shall be used. 2. Indoor design conditions. Indoor design temperature and humidity conditions for comfort applications shall be determined in accordance with Subsection A or B below:

  A. For systems serving hotel/motel buildings, and nonresidential buildings other than healthcare facilities, ASHRAE Standard 55 or the 2017 ASHRAE Handbook, Fundamentals Volume, except that winter humidification and summer dehumidification shall not be required. B. For systems serving healthcare facilities the method in the California Mechanical Code shall be used. 3. **Outdoor design conditions.

• CMC § 170.2 Medium relevance — show source text

  5. All skylights shall have a glazing material or diffuser that has a measured haze value greater than 90 percent, tested according to ASTM D1003 (notwithstanding its scope) or another test method approved by the Commission. Exception 1 to Section 170.2(b): In buildings with unfinished interiors, future enclosed spaces for which there are plans to have:

  A. A floor area of less than or equal to 5,000 square feet; or B. Ceiling heights of less than or equal to 15 feet. This exception shall not be used for S-1 or S-2 (storage), or for F-1 or F2 (factory) occupancies. Exception 2 to Section 170.2(b): Enclosed spaces having a designed general lighting system with a lighting power density less than 0.5 watts per square foot. Exception 3 to Section 170.2(b): Enclosed spaces where it is documented that permanent architectural features of the building, existing structures or natural objects block direct beam sunlight on at least half of the roof over the enclosed space for more than 1500 daytime hours per year between 8 a.m. and 4 p.m.

  (c) Space-conditioning systems. All space heating, space cooling and ventilation equipment shall comply with minimum Appliance Efficiency Regulations as specified in Sections 110.0 through 110.2 and the applicable requirements of Subsections 1 through 4.

  1. Sizing and equipment selection—common use areas. Mechanical heating and mechanical cooling equipment serving common use areas of multifamily buildings shall be the smallest size, within the available options of the desired equipment line, necessary to meet the design heating and cooling loads of the building, as calculated according to Subsection 2 below. Exception 1 to Section 170.2(c)1: Where it can be demonstrated to the satisfaction of the enforcing agency that oversizing will not increase building LSC energy use. Exception 2 to Section 170.2(c)1: Standby equipment with controls that allow the standby equipment to operate only when the primary equipment is not operating. Exception 3 to Section 170.2(c)1: Multiple units of the same equipment type, such as multiple chillers and boilers, having combined capacities exceeding the design load, if they have controls that sequence or otherwise optimally control the operation of each unit based on load.
  2. Calculations—common use areas. In making equipment sizing calculations under Subsection (c)1, all of the following rules shall apply: A. Heating and cooling loads. Heating and cooling system design loads shall be determined in accordance with the method in the 2021 ASHRAE Handbook, Fundamentals Volume, or as specified in a method approved by the Commission.

  B. Indoor design conditions. Indoor design temperature and humidity conditions for comfort applications shall be determined using ASHRAE Standard 55 or the 2021 ASHRAE Handbook, Fundamentals Volume, except that winter humidification and summer dehumidification shall not be required. C. Outdoor design conditions. Outdoor design conditions shall be selected from Reference Joint Appendix JA2, which is based on data from the ASHRAE Climatic Data for Region X or the ASHRAE Handbook, Fundamentals Volume. Heating design temperatures shall be no lower than the 99.0 percent Heating Dry Bulb or the Heating Winter Median of Extremes values. Cooling design temperatures shall be no greater than the 0.5 percent Cooling Dry Bulb and Mean Coincident Wet Bulb values.

• CMC § 150.0 Medium relevance — show source text

  2. In Climate Zones 14 and 16, a Class I or Class II vapor retarder shall be installed on the conditioned space side of all insulation in all exterior walls, vented attics and unvented attics with air-permeable insulation.

  (h) Space-conditioning equipment.

  1. Building cooling and heating loads. Building heating and cooling loads shall be determined using a method based on any one of the following: A. The ASHRAE Handbook, Equipment Volume, Applications Volume and Fundamentals Volume; or B. The SMACNA Residential Comfort System Installation Standards Manual; or

  C. The ACCA Manual J.

  Exception 1 to Section 150.0(h)1: Block loads, the total load for all rooms combined that are served by the central equipment, may be used for the purpose of system sizing for additions. 2. Design conditions. Design conditions shall be determined in accordance with the following: A. For the purpose of sizing the space-conditioning (HVAC) system, the indoor design temperatures shall be 68°F for heating and 75°F for cooling. B. Outdoor design conditions shall be selected from one of the following: i. Reference Joint Appendix JA2, which is based on data from the ASHRAE Climatic Data for Region X; or ii. The ASHRAE Handbook, Fundamentals Volume; or

  iii. The ACCA Manual J.

  C. The outdoor design temperatures for heating shall be no lower than the 99.0 percent Heating Dry Bulb or the Heating Winter Median of Extremes values.

  D. The outdoor design temperatures for cooling shall be no greater than the 1.0 percent Cooling Dry Bulb and Mean Coincident Wet Bulb values.

  3. Outdoor condensing units. A. Clearances. Installed air conditioner and heat pump outdoor condensing units shall have a clearance of at least five (5) feet (1.5 meters) from the outlet of any dryer vent. B. Liquid line drier. Installed air conditioner and heat pump systems shall be equipped with liquid line filter driers if required, as specified by manufacturer’s instructions.
  4. Central forced-air heating furnaces. A. Temperature rise. Central forced-air heating furnace installations shall be configured to operate in conformance with the furnace manufacturer’s maximum inlet-to-outlet temperature rise specifications.
  5. System selection. A. Equipment sizing and selection shall meet the cooling and heating loads of Sections 150.0(h)1 and 2. B. Systems shall be sized based on ACCA Manual S-2023 in accordance with these requirements: i. Cooling capacity: There is no limit on the minimum capacity. ii. Furnaces: Heating capacity shall be sized based on ACCA Manual S-2023, Table N2.5.

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  SINGLE-FAMILY RESIDENTIAL BUILDINGS— MANDATORY FEATURES AND DEVICES

  iii. Heat pump heating capacity: a. Minimum: Heating systems are required to have a heating capacity meeting the minimum requirements of the CBC, not including any supplementary heating. b. Maximum: There is no limit on the maximum heating capacity.

  6. Defrost.
• CMC § 90.1 Medium relevance — show source text

  (5) A complete narrative of how each system is intended to operate, including suggested setpoints. [ASHRAE 90.1:6.7.3.2] E 503.6.5.3 System Balancing. Construction documents shall require that HVAC systems be balanced in accordance with generally accepted engineering standards. Construction documents shall require that a written balance report be provided to the building owner or the designated representative of the building owner for HVAC systems serving a total conditioned space or zone exceeding 5000 square feet (464.52 m [2] ). {ASHRAE 90.1:6.7.3.3.1}

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  APPENDIX E

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  E 503.6.5.3.1 Air System Balancing. Air systems shall be balanced in a manner to first minimize throttling losses. Then, for fans with fan system power greater than 1 hp (0.7 kW), fan speed shall be adjusted to meet design flow conditions. [ASHRAE 90.1:6.7.3.3.2]

  E 503.6.5.3.2 Hydronic System Balanc- ing. Hydronic systems shall be proportionately balanced in a manner to first minimize throt tling losses; then the pump impeller shall be trimmed or pump speed shall be adjusted to meet design flow conditions.

  Exceptions: Impellers need not be trimmed nor pump speed adjusted.

  (1) For pumps with pump motors of 10 hp (7.5 kW) or less.

  (2) Where throttling results is not greater than 5 percent of the nameplate horsepower draw, or 3 hp (2.2 kW), whichever is greater, above that required where the impeller was trimmed. [ASHRAE 90.1:6.7.3.3]

  E 503.6.5.4 Minimum Level of Commission.

  Commissioning shall be performed for HVAC systems in accordance with Level 1, Basic Commissioning of the SMACNA HVAC Systems Commissioning Manual. (See Section E 801.0 for additional information on HVAC system commissioning)

  E 503.7 Minimum Equipment Efficiency Tables. The minimum efficiency requirements for equipment shall comply with Section E 503.7.1; duct insulation shall comply with Section E 503.7.2, and pipe insulation shall comply with Section E 503.7.3.

  E 503.7.1 Minimum Efficiency Requirement Listed Equipment – Standard Rating and Oper- ating Conditions. The minimum efficiency requirements for equipment shall comply with Table E 503.7.1(1) through Table E 503.7.1(20).

  E 503.7.2 Duct Insulation Tables. Duct insulation

  shall comply with Table E 503.7.2.

  E 503.7.3 Pipe Insulation Tables. Pipe insulation shall comply with Table E 503.7.3(1) and Table E 503.7.3(2).

• CEC § 384 Medium relevance — show source text

  384 2025 CALIFORNIA MECHANICAL CODE

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  APPENDICES

  The appendices are intended to supplement the provisions of the installation requirements of this code. The definitions in Chapter 2 are also applicable to the appendices.

  TABLE OF CONTENTS

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  Appendix A Page

  Residential Plans Examiner Review Form for HVAC System Design..............................................................387

  Appendix B

  Procedures to be Followed to Place Gas Equipment in Operation..................................................................391

  Appendix C

  Installation and Testing of Oil (Liquid) Fuel-Fired Equipment ..........................................................................395

  Appendix D

  Fuel Supply: Manufactured/Mobile Home Parks and Recreational Vehicle Parks ..........................................403

  Appendix E

  Sustainable Practices ......................................................................................................................................411

  Appendix F

  Sizing of Venting Systems and Outdoor Combustion and Ventilation Opening Design ..................................533

  Appendix G

  Example Calculation of Outdoor Air Rate........................................................................................................545

  Appendix H

  Professional Qualifications ..............................................................................................................................549

  Appendix I

  Indoor Horticultural Facilities ..........................................................................................................................553

  Appendix J

  Clean Air Delivery............................................................................................................................................559

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  CALIFORNIA MECHANICAL CODE – MATRIX ADOPTION TABLE

  APPENDIX A – RESIDENTIAL PLAN EXAMINER REVIEW FORM FOR HVAC SYSTEM DESIGN

  (Matrix Adoption Tables are non-regulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

  Adopting Agency	BSC	BSC- CG	SFM	HCD	Col6	Col7	DSA	Col9	Col10	OSHPD	Col12	Col13	Col14	Col15	Col16	Col17	BSCC	DPH	AGR	DWR	CEC	CA	SL	SLC
  Adopting Agency	BSC	BSC- CG	SFM	1	2	1-AC	AC	** SS**	** SS/CC**	1	1R	2	3	4	5	6	6	6	6	6	6	6	6	6
  Adopt Entire Chapter
  Adopt Entire Chapter as amended (amended sections listed below)
  Adopt only those sections that are listed below
  Chapter/Section

• CMC § 160.3 Medium relevance — show source text

  e. Excess outdoor air.

  viii. The FDD system shall be certified to the Energy Commission as meeting the requirements of Sections 160.3(a)2Hi through 160.3(a)2Hvii in accordance with Section 110.0 and JA6.3. Exception to Section 160.3(a)2Hviii: FDD algorithms based in direct digital control systems are not required to be certified to the Energy Commission. I. Direct digital controls (DDC). Direct digital controls to the zone shall be provided as specified by Table 160.3-C. i. The provided DDC system shall meet the control logic requirements of Sections 160.3(a)2E and 160.3(a)2G, and be capable of the following: ii. Monitoring zone and system demand for fan pressure, pump pressure, heating and cooling; iii. Transferring zone and system demand information from zones to air distribution system controllers and from air distribution systems to heating and cooling plant controllers; iv. Automatically detecting the zones and systems that may be excessively driving the reset logic and generate an alarm or other indication to the system operator; v. Readily allow operator removal of zone(s) from the reset algorithm; vi. For new buildings, trending and graphically displaying input and output points; and vii. Resetting heating and cooling setpoints in all noncritical zones upon receipt of a signal from a centralized contact or software point as described in Section 160.3(a)2G. J. 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 160.3(a)2J: Systems that must operate continuously.

  (b) Dwelling unit space-conditioning and air distribution systems.

  1. Building cooling and heating loads. Building heating and cooling loads shall be determined using a method based on any one of the following, using cooling and heating loads as two of the criteria for equipment sizing and selection: A. The ASHRAE Handbook, Equipment Volume, Applications Volume and Fundamentals Volume; or B. The SMACNA Residential Comfort System Installation Standards Manual; or

  C. The ACCA Manual J.

  Exception to Section 160.3(b)1: Block loads, the total load for all rooms combined that are served by the central equipment, may be used for the purpose of system sizing for additions. NOTE: Heating systems are required to have a minimum heating capacity adequate to meet the minimum requirements of the CBC.

  2. Design conditions . Design conditions shall be determined in accordance with the following: A. For the purpose of sizing the space-conditioning (HVAC) system, the indoor design temperatures shall be 68°F for heating and 75°F for cooling. B. Outdoor design conditions shall be selected from one of the following: i. Reference Joint Appendix JA2, which is based on data from the ASHRAE Climatic Data for Region X; or ii. The ASHRAE Handbook Fundamentals Volume; or

  iii. The ACCA Manual J.

  C. The outdoor design temperatures for heating shall be no lower than the 99.0 percent Heating Dry Bulb or the Heating Winter Median of Extremes values.

• CMC § 0.249 Medium relevance — show source text

  = 0.249 kPa = 0.249 kPa

  Notes: Notes: 1 CTS = Copper tube size. 1 CTS = Copper tube size. 2 Table entries are rounded to 3 significant digits. 2 Table entries are rounded to 3 significant digits. 3 NA means a flow of less than 10 ft 3 /h (0.283 m 3 /h). 3 NA means a flow of less than 10 ft 3 /h (0.283 m 3 /h).

  For SI units: 1 inch = 25 mm, 1 foot = 304.8 mm, 1 cubic foot per hour = 0.0283m [3] /h, 1 pound-force per square inch = 6.8947 kPa, 1 inch water column

  = 0.249 kPa

  Notes: 1 CTS = Copper tube size. 2 Table entries are rounded to 3 significant digits. 3 NA means a flow of less than 10 ft 3 /h (0.283 m 3 /h).

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  FUEL GAS PIPING

  TABLE 1315.2(24) SCHEDULE 40 METALLIC PIPE [NFPA 54: TABLE 6.3.1(a)]*	Col2	Col3	Col4	Col5	Col6	Col7	Col8	Col9	Col10
  						GAS:	GAS:	UNDILUTED PROPANE	UNDILUTED PROPANE
  						INLET PRESSURE:	INLET PRESSURE:	10.0 psi	10.0 psi
  						PRESSURE DROP:	PRESSURE DROP:	1.0 psi	1.0 psi
  						SPECIFIC GRAVITY:	SPECIFIC GRAVITY:	1.50	1.50
  INTENDED USE: PIPE SIZING BETWEEN FIRST STAGE (HIGH PRESSURE) REGULATOR AND SECOND STAGE (LOW PRESSURE) REGULATOR	INTENDED USE: PIPE SIZING BETWEEN FIRST STAGE (HIGH PRESSURE) REGULATOR AND SECOND STAGE (LOW PRESSURE) REGULATOR	INTENDED USE: PIPE SIZING BETWEEN FIRST STAGE (HIGH PRESSURE) REGULATOR AND SECOND STAGE (LOW PRESSURE) REGULATOR	INTENDED USE: PIPE SIZING BETWEEN FIRST STAGE (HIGH PRESSURE) REGULATOR AND SECOND STAGE (LOW PRESSURE) REGULATOR	INTENDED USE: PIPE SIZING BETWEEN FIRST STAGE (HIGH PRESSURE) REGULATOR AND SECOND STAGE (LOW PRESSURE) REGULATOR	INTENDED USE: PIPE SIZING BETWEEN FIRST STAGE (HIGH PRESSURE) REGULATOR AND SECOND STAGE (LOW PRESSURE) REGULATOR	INTENDED USE: PIPE SIZING BETWEEN FIRST STAGE (HIGH PRESSURE) REGULATOR AND SECOND STAGE (LOW PRESSURE) REGULATOR	INTENDED USE: PIPE SIZING BETWEEN FIRST STAGE (HIGH PRESSURE) REGULATOR AND SECOND STAGE (LOW PRESSURE) REGULATOR	INTENDED USE: PIPE SIZING BETWEEN FIRST STAGE (HIGH PRESSURE) REGULATOR AND SECOND STAGE (LOW PRESSURE) REGULATOR	**INTENDED USE: PIPE SIZING

• CMC § 150.0 Medium relevance — show source text

  Closable metal or glass doors covering the entire opening of the firebox; and 2. A combustion air intake to draw air from the outside of the building, which is at least 6 square inches in area and is equipped with a readily accessible, operable and tight-fitting damper or combustion-air control device; and Exception to Section 150.0(e)2: An outside combustion-air intake is not required if the fireplace will be installed over concrete slab flooring and the fireplace will not be located on an exterior wall. 3. A flue damper with a readily accessible control. Exception to Section 150.0(e)3: When a gas log, log lighter or decorative gas appliance is installed in a fireplace, the flue damper shall be blocked open if required by the CMC or the manufacturer’s installation instructions.

  (f) Slab edge insulation. Material used for slab edge insulation shall meet the following minimum specifications:

  1. Water absorption rate for the insulation material alone without facings no greater than 0.3 percent when tested in accordance with Test Method A – 24-Hour-Immersion of ASTM C272.

  2. Water vapor permeance no greater than 2.0 perm/inch when tested in accordance with ASTM E96.

  3. Concrete slab perimeter insulation shall be protected from physical damage and ultraviolet light deterioration.

  4. Insulation for a heated slab floor shall meet the requirements of Section 110.8(g).

  (g) Vapor retarder.

  1. In Climate Zones 1–16, the earth floor of unvented crawl space shall be covered with a Class I or Class II vapor retarder. This requirement shall also apply to controlled ventilation crawl space for buildings complying with the Exception to Section 150.0(d).

  2. In Climate Zones 14 and 16, a Class I or Class II vapor retarder shall be installed on the conditioned space side of all insulation in all exterior walls, vented attics and unvented attics with air-permeable insulation.

  (h) Space-conditioning equipment.

  1. Building cooling and heating loads. Building heating and cooling loads shall be determined using a method based on any one of the following: A. The ASHRAE Handbook, Equipment Volume, Applications Volume and Fundamentals Volume; or B. The SMACNA Residential Comfort System Installation Standards Manual; or

  C. The ACCA Manual J.

  Exception 1 to Section 150.0(h)1: Block loads, the total load for all rooms combined that are served by the central equipment, may be used for the purpose of system sizing for additions. 2. Design conditions. Design conditions shall be determined in accordance with the following: A. For the purpose of sizing the space-conditioning (HVAC) system, the indoor design temperatures shall be 68°F for heating and 75°F for cooling. B. Outdoor design conditions shall be selected from one of the following: i. Reference Joint Appendix JA2, which is based on data from the ASHRAE Climatic Data for Region X; or ii. The ASHRAE Handbook, Fundamentals Volume; or

  iii. The ACCA Manual J.

  C. The outdoor design temperatures for heating shall be no lower than the 99.0 percent Heating Dry Bulb or the Heating Winter Median of Extremes values.

  D. The outdoor design temperatures for cooling shall be no greater than the 1.0 percent Cooling Dry Bulb and Mean Coincident Wet Bulb values.

  3. Outdoor condensing units. A. **Clearances.