1、 2015CODE AND COMMENTARYThe complete IRC with commentary after each sectionVOLUME 2IRC2015 International Residential CodeCommentaryVolume IIFirst Printing: August 2015ISBN: 978-1-60983-285-8 (soft-cover edition)COPYRIGHT 2015byINTERNATIONAL CODE COUNCIL, INC.ALL RIGHTS RESERVED. This 2015 Internatio
2、nal Residential CodeCommentaryVolume II is a copyrighted work ownedby the International Code Council, Inc. Without advance written permission from the copyright owner, no part of this book maybe reproduced, distributed or transmitted in any form or by any means, including, without limitation, electr
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4、ne 1-888-ICC-SAFE (422-7233).Trademarks: “International Code Council,” the “International Code Council” logo and the “International Residential Code” aretrademarks of the International Code Council, Inc. PRINTED IN THE U.S.A.2015 INTERNATIONAL RESIDENTIAL CODECOMMENTARY iiiPREFACEThe principal purpo
5、se of the Commentary is to provide a basic volume of knowledge and facts relating to building constructionas it pertains to the regulations set forth in the 2015 International Residential Code. The person who is serious about effectivelydesigning, constructing and regulating buildings and structures
6、 will find the Commentary to be a reliable data source and refer-ence to almost all components of the built environment.As a follow-up to the International Residential Code, we offer a companion document, the International Residential CodeCommentaryVolume II. Volume II covers Chapters 12 through App
7、endix Q of the 2015 International Residential Code. Thebasic appeal of the Commentary is thus: it provides, in a small package and at reasonable cost, thorough coverage of manyissues likely to be dealt with when using the International Residential Code and then supplements that coverage with histori
8、-cal and technical background. Reference lists, information sources and bibliographies are also included.Throughout all of this, strenuous effort has been made to keep the vast quantity of material accessible and its method of pre-sentation useful. With a comprehensive yet concise summary of each se
9、ction, the Commentary provides a convenient referencefor regulations applicable to the construction of buildings and structures. In the chapters that follow, discussions focus on the fullmeaning and implications of the code text. Guidelines suggest the most effective method of application, and the c
10、onsequences ofnot adhering to the code text. Illustrations are provided to aid understanding; they do not necessarily illustrate the only methodsof achieving code compliance.The format of the Commentary includes the full text of each section, table and figure in the code, followed immediately by the
11、commentary applicable to that text. At the time of printing, the Commentary reflects the most up-to-date text of the 2015 Inter-national Residential Code. Each sections narrative includes a statement of its objective and intent, and usually includes a discus-sion about why the requirement commands t
12、he conditions set forth. Code text and commentary text are easily distinguished fromeach other. All code text is shown as it appears in the International Residential Code, and all commentary is indented below thecode text and begins with the symbol . All code figures and tables are reproduced as the
13、y appear in the IRC. Commentary fig-ures and tables are identified in the text by the word “Commentary” (as in “see Commentary Figure 704.3”), and each has a fullborder.Readers should note that the Commentary is to be used in conjunction with the International Residential Code and not as asubstitute
14、 for the code. The Commentary is advisory only; the code official alone possesses the authority and responsibility forinterpreting the code.Comments and recommendations are encouraged, for through your input, we can improve future editions. Please direct yourcomments to the Codes and Standards Devel
15、opment Department at the Central Regional Office.iv 2015 INTERNATIONAL RESIDENTIAL CODECOMMENTARY 2015 INTERNATIONAL RESIDENTIAL CODE COMMENTARY vTABLE OF CONTENTSPart VMechanicalCHAPTER 12 MECHANICAL ADMINISTRATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16、. . 12-1 12-2CHAPTER 13 GENERAL MECHANICAL SYSTEM REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1 13-18CHAPTER 14 HEATING AND COOLING EQUIPMENT AND APPLIANCES . . . . . . . . . . . . . . . . . . . . . 14-1 14-16CHAPTER 15 EXHAUST SYSTEMS . . . . . . . . . . . . . . . . . . . .
17、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1 15-14CHAPTER 16 DUCT SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16-1 16-20CHAPTER 17 COMBUSTION AIR . . . . . . . . . . . . . . . . .
18、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17-1 17-2CHAPTER 18 CHIMNEYS AND VENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-1 18-14CHAPTER 19 SPECIAL APPLIANCES, EQUIPMENT AND SYSTEMS . . . .
19、. . . . . . . . . . . . . . . . . . . . . . . 19-1 19-4CHAPTER 20 BOILERS AND WATER HEATERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1 20-8CHAPTER 21 HYDRONIC PIPING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、 . . . . . . . . . . . . . . . . 21-1 21-10CHAPTER 22 SPECIAL PIPING AND STORAGE SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-1 22-4CHAPTER 23 SOLAR THERMAL ENERGY SYSTEMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23-1 23-8
21、Part VIFuel GasCHAPTER 24 FUEL GAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-1 24-264Part VIIPlumbingCHAPTER 25 PLUMBING ADMINISTRATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22、. . . . . . . . . . . 25-1 25-6CHAPTER 26 GENERAL PLUMBING REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26-1 26-22CHAPTER 27 PLUMBING FIXTURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-1
23、 27-24CHAPTER 28 WATER HEATERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28-1 28-12CHAPTER 29 WATER SUPPLY AND DISTRIBUTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29-1 29-78CHAPTER 30
24、SANITARY DRAINAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1 30-38CHAPTER 31 VENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31-1 31-
25、26vi 2015 INTERNATIONAL RESIDENTIAL CODE COMMENTARYTABLE OF CONTENTSCHAPTER 32 TRAPS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32-1 32-4CHAPTER 33 STORM DRAINAGE. . . . . . . . . . . . . . . . . . . .
26、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33-1 33-4Part VIIIElectricalCHAPTER 34 GENERAL REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34-1 34-20CHAPTER 35 ELECTRICAL DEFINITIONS . . . . . . . . . .
27、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35-1 35-18CHAPTER 36 SERVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36-1 36-32CHAPTER 37 BRANCH CIRCUIT AND FEEDER REQUIREMENTS
28、. . . . . . . . . . . . . . . . . . . . . . . . . . . . 37-1 37-22CHAPTER 38 WIRING METHODS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38-1 38-10CHAPTER 39 POWER AND LIGHTING DISTRIBUTION . . . . . . . . . . . . . . . . . . . .
29、. . . . . . . . . . . . . . . . . . 39-1 39-48CHAPTER 40 DEVICES AND LUMINAIRES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40-1 40-14CHAPTER 41 APPLIANCE INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30、. . . . . . . . . . 41-1 41-6CHAPTER 42 SWIMMING POOLS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42-1 42-18CHAPTER 43 CLASS 2 REMOTE-CONTROL, SIGNALING ANDPOWER-LIMITED CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . .
31、 . . . . . . . . . . . . . . . . . . . . . . . . . 43-1 43-4Part IXReferenced StandardsCHAPTER 44 REFERENCED STANDARDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44-1 44-28APPENDIX A SIZING AND CAPACITIES OF GAS PIPING . . . . . . . . . . . .
32、. . . . . . . . . . . . . . . . . . . . . . . . . . .A1 A12APPENDIX B SIZING OF VENTING SYSTEMS SERVINGAPPLIANCES EQUIPPED WITH DRAFT HOODS,CATEGORY I APPLIANCES, AND APPLIANCESLISTED FOR USE WITH TYPE B VENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1 B-10AP
33、PENDIX C EXIT TERMINALS OF MECHANICAL DRAFTAND DIRECT-VENT VENTING SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1 C-2APPENDIX D RECOMMENDED PROCEDURE FOR SAFETYINSPECTION OF AN EXISTING APPLIANCE INSTALLATION . . . . . . . . . . . . . . . . . . . . . D-1
34、D-6APPENDIX E MANUFACTURED HOUSING USED AS DWELLINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1 E-14APPENDIX F PASSIVE RADON GAS CONTROLS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .F-1 F-10APPENDIX G PIPING STANDARDS FOR VARIOUS APPLICA
35、TIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . G-1 G-62015 INTERNATIONAL RESIDENTIAL CODE COMMENTARY viiTABLE OF CONTENTSAPPENDIX H PATIO COVERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H-1 H-6APPENDI
36、X I PRIVATE SEWAGE DISPOSAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I-1 I-2APPENDIX J EXISTING BUILDINGS AND STRUCTURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J-1 J-10APPENDIX K SOUND TRANSMISSION . .
37、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . K-1 K-2APPENDIX L PERMIT FEES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L-1 L-2APPENDIX M HOME DAY CARER-3
38、 OCCUPANCY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M-1 M-2APPENDIX N VENTING METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N-1 N-6APPENDIX O AUTOMATIC VEHICULAR GATES. . . . . . .
39、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O-1 O-2APPENDIX P SIZING OF WATER PIPING SYSTEM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P-1 P-20APPENDIX Q RESERVED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
40、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Q1 Q-2APPENDIX R LIGHT STRAW-CLAY CONSTRUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .R1 R10APPENDIX S STRAWBALE CONSTRUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
41、 . . . . . . . . . . . . . . . . . . . . . S1 S28APPENDIX T RECOMMENDED PROCEDURE FOR WORST-CASE TESTINGOF ATMOSPHERIC VENTING SYSTEMS UNDER N1102.4 ORN1105 CONDITIONS 5ACH50. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T1 T4APPENDIX U SOLAR-R
42、EADY PROVISIONSDETACHED ONE- ANDTWO-FAMILY DWELLINGS, MULTIPLE SINGLE-FAMILYDWELLINGS (TOWNHOUSES). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .U1 U2INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
43、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . INDEX-1 INDEX-14viii 2015 INTERNATIONAL RESIDENTIAL CODE COMMENTARY 2015 INTERNATIONAL RESIDENTIAL CODECOMMENTARY 12-1SECTION M1201GENERALM1201.1 Scope. The provisions of Chapters 12 through 24shall regulate the design, installation, ma
44、intenance, alterationand inspection of mechanical systems that are permanentlyinstalled and used to control environmental conditions withinbuildings. These chapters shall also regulate those mechani-cal systems, system components, equipment and appliancesspecifically addressed in this code. This sec
45、tion lists the chapters in the code that regulatemechanical systems. It indicates that the design,installation, and maintenance of mechanical equip-ment used to control the environmental conditionswithin the building are regulated by these chapters. Italso states that other mechanical systems specif
46、icallyaddressed within these chapters are so regulated.Other provisions in the code reference the Interna-tional Mechanical Code(IMC) and the InternationalFuel Gas Code(IFGC). This regulates virtually allmechanical systems and equipment within a dwellingin some form or another.M1201.2 Application. I
47、n addition to the general administra-tion requirements of Chapter 1, the administrative provisionsof this chapter shall also apply to the mechanical require-ments of Chapters 13 through 24. This section makes reference to the administrativerequirements of Chapter 1 to include those administra-tive p
48、rovisions and make them applicable to themechanical chapters.SECTION M1202EXISTING MECHANICAL SYSTEMS M1202.1 Additions, alterations or repairs. Additions, alter-ations, renovations or repairs to a mechanical system shallconform to the requirements for a new mechanical systemwithout requiring the existing mechanical system to complywith all of the requirements of this code. Additions, altera-tions or repairs shall not cause an existing mechanical systemto become unsafe, hazardous or overloaded. Minor additions,alt
