Significant Changes to the International Residential Code 1337271330, 9781337271332

Table of contents :
Cover
Contents
Preface
Part 1: Administration: Chapters 1 and 2
R101.2 Scope
R104.11 Alternative Materials and Methods of Construction
R105.1, R110.1, R202 Change of Occupancy
R202 Definition of Access
R202 Definition of Crawl Space
R202 Definition of Carbon Monoxide Alarm
R202 Definition of Fenestration
R202 Definition of Solar Energy System
Part 2: Building Planning: Chapter 3
Table R301.2(1) Climatic and Geographic Design Criteria
R301.2.2.1 Seismic Design Category
R301.2.2.6 Irregular Buildings
R302.1 Exterior Walls
R302.2 Townhouse Separation
R302.3 Two-Family Dwelling Separation
R302.4.2 Membrane Penetrations
R302.5 Dwelling-Garage Opening Protection
R302.10 Insulation Flame Spread
R302.13 Fire Protection of Floors above Crawl Spaces
R308.4.2 Glazing Adjacent to Doors
R308.4.4 Glazing in Guards and Railings
R308.4.7 Glazing Adjacent to the Bottom Stair Landing
R310.1 Emergency Escape and Rescue Openings
R310.3 Area Wells for Emergency Escape and Rescue Doors
R311.7.1, R311.7.8 Handrail Projection
R311.7.3 Maximum Stair Rise between Landings
R311.7.5.3 Stair Nosings
R311.7.11, R311.7.12 Alternating Tread Devices and Ships Ladders
R312.1 Guards
R314 Smoke Alarms
R315 Carbon Monoxide Alarms
R317.3 Fasteners in Treated Wood
R322.3 Coastal High-Hazard Flood Zones
R324.4 Rooftop-Mounted Photovoltaic Systems
R324.6 Roof Access for Photovoltaic Solar Energy Systems
R324.6.2.2 Solar Panels Near Emergency Escape and Rescue Openings
R325.3 Mezzanine Area Limitation
R325.6, R202 Habitable Attics
Part 3: Building Construction: Chapters 4 through 10
Table R403.3(1) Insulation Requirements for Frost-Protected Footings
Table R403.4 Crushed Stone Footings
R408.3 Unvented Crawl Spaces
Table R505.3.2 Cold-Formed Steel Joist Spans
R507 Decks
R507.2 Deck Materials
R507.3 Deck Footings
R507.4 Deck Posts
R507.5 Deck Beams
R507.6 Deck Joists
R507.7, R507.8, R507.9 Decking, Vertical and Lateral Support
Table R602.3(6) Alternate Stud Height
Tables R602.7(1), R602.7(2) Girder and Header Spans
Table R602.7.5 Lateral Support for Headers
Table R602.10.3(4) Seismic Adjustment Factors
R602.10.4.1 Mixing Bracing Methods
R602.10.6.4 Method CS-PF-Continuously Sheathed Portal Frame
R602.10.6.5 Method BV-WSP
Tables R603.3.1 and R603.3.1.1(2) Cold-Formed Steel Wall Construction
Section R610 Structural Insulated Panels
R703.2 Water-Resistive Barrier
R703.3.1 Soffit Installation
R703.8.4 Veneer Anchorage through Insulation
Table R703.8.4(1) Airspace Requirements
R703.11.2 Vinyl Siding Installation over Foam Plastic Sheathing
R802 Roof Framing
R802.1.5.4 Labeling
R806.2 Minimum Vent Area
R806.5 Unvented Attics
Tables R905.1.1(1) and R905.1.1(2) Underlayment Requirements for Photovoltaic Shingles
R905.17 Building Integrated Photovoltaic Panels
R1005.8 Chimney Insulation Shield
Part 4: Energy Conservation: Chapter 11
N1101.6 Definition of Air Barrier
N1101.6 Definition of Building Thermal Envelope
N1101.6, Tables N1101.10.3(1) and N1101.10.3(2) Fenestration Definitions and U-Factors
N1102.1 Building Thermal Envelope for Log Homes
Tables N1102.1.2 and N1102.1.4 Insulation and Fenestration Requirements
N1102.2.2 Reduction of Ceiling Insulation
N1102.2.5 Mass Walls
Table N1102.2.6 Cold-Formed Steel Framing R-Values
N1102.4 Testing for Air Leakage
N1103.3.2, N1103.3.3 Duct Sealing and Testing
N1103.3.6, N1103.3.7 Ducts Buried within Ceiling Insulation
N1104.1 Lighting
N1106.3, N1106.4 Maximum Energy Rating Index
Part 5: Mechanical: Chapters 12 through 23
M1305.1.1 Access to Furnaces within Compartments
M1305.1.3.2 Appliances Installed in Pits
M1502.3.1 Dryer Exhaust Duct Termination
M1502.4.2 Concealed Dryer Exhaust Ducts
M1503 Domestic Cooking Exhaust Equipment
M1503.6 Makeup Air for Kitchen Exhaust Systems
M1601.1.2 Underground Duct Systems
M1901 Ranges and Ovens
Table M2101.9 Hanger Spacing for PEX Tubing
M2101.10 Pressure Tests for Hydronic Piping
M2103.2 Thermal Barrier for Radiant Floor Heating Systems
M2301 Solar Thermal Energy Systems
Part 6: Fuel Gas: Chapter 24
G2406.2 Prohibited Locations for Appliances
G2411.2, G2411.3 Electrical Bonding of CSST
G2414.4.2, G2414.10.1 Schedule 10 Steel Gas Piping
G2415.11 Protection against Corrosion
G2420.5.1 Shutoff Valve Location
G2420.6 Support for Shutoff Valves in Tubing Systems
G2442.2 Forced Air Furnace Duct Size
G2447.2 Commercial Cooking Appliances
Part 7: Plumbing: Chapters 25 through 33
P2503.7 Air Testing of PEX Piping
P2602.1 Connections to Public Sewer or Private Sewage Disposal System
P2605 Sway Bracing for Drainage Piping
P2704 Slip Joint Connections
P2713.1 Bathtub Overflow
P2801.6 Plastic Pan for Gas-Fired Water Heaters
P2902.5.4, P2904.1 Backflow Protection for Fire Sprinkler Systems
P2903.5 Water Hammer Arrestors
P2906.6.1 Saddle Tap Fittings on Water Distribution Piping
P2906.18.2 Joints between PVC and CPVC Piping
P3003.2 Prohibited Joints for Sanitary Drainage
P3005.1.6 Reduction in Pipe Size
P3103.1 Vent Pipe Terminations
P3111 Combination Waste and Vent System
P3114.8 Prohibited Installations for Air Admittance Valves
Part 8: Electrical: Chapters 34 through 43
E3703.5 Garage Branch Circuits
E3901.2 Wall Space for Receptacle Distribution
E3901.3 Appliances on 15 Amp Circuits
E3901.9 Garage Receptacle Outlet Location
E3902.4 GFCI Protection for Crawl Space Lighting Outlets
E3906.3 Nonmetallic-Sheathed Cable and Metal Boxes
E4101.3 Cord-and-Plug-Connected Appliances
Part 9: Appendices: Appendix A through T
Appendix Q Tiny Houses
Appendix R Light Straw-Clay Construction
Appendix S Strawbale Construction
Appendix T Solar-Ready Zone
Index

Citation preview

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203

Significant Changes to the

International residential ® Code 2018 Edition

Australia

●

Brazil

●

Mexico

●

Singapore

●

United Kingdom

●

United States

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

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Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the ­International Residential Code® 2018 Edition

© 2018 International Code Council

­International Code Council

ALL RIGHTS RESERVED. No part of this work covered by the copyright herein may be

Stephen A. Van Note and Sandra Hyde, P.E.

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Printed in United States of America Print Number: 01   Print Year: 2017 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Contents

PART 1 Administration Chapters 1 and 2

■ R301.2.2.1

Seismic Design Category

1

Scope 2 Alternative Materials and Methods of Construction

5

R105.1, R110.1, R202 Change of Occupancy

7

■ R202

Definition of Access

9

■ R202

Definition of Crawl Space

11

■ R202

Definition of Carbon Monoxide Alarm

12

■ R202

Definition of Fenestration

14

■ R202

Definition of Solar Energy System

16

■

Table R301.2(1) Climatic and Geographic Design Criteria

32

■ R302.2

Townhouse Separation

37

■ R302.3

Two-Family Dwelling Separation

41

■ R302.4.2

Membrane Penetrations

43

■ R302.5

Dwelling-Garage Opening Protection

45

■ R302.10

Insulation Flame Spread

47

■ R302.13

Fire Protection of Floors above Crawl Spaces 49 ■ R308.4.2

Glazing Adjacent to Doors

PART 2 Building Planning Chapter 3

29

■ R302.1

Exterior Walls

■ R104.11

■

■ R301.2.2.6

Irregular Buildings

■ R101.2

23

51

■ R308.4.4

Glazing in Guards and Railings

18 20

53

■ R308.4.7

Glazing Adjacent to the Bottom Stair Landing

55

iii Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

iv  Contents ■ R310.1

■

Emergency Escape and Rescue Openings

56

■ R310.3

■

58

R311.7.1, R311.7.8 Handrail Projection

61

■

■ R311.7.5.3

Stair Nosings

66

R311.7.11, R311.7.12 Alternating Tread Devices and Ships Ladders 67

100

Table R505.3.2 Cold-Formed Steel Joist Spans

102

■ R507

■ R507.2

Deck Materials

106

■ R507.3

Deck Footings

109

■ R507.4

Deck Posts

113

■ R507.5

■ R312.1

Deck Beams

Guards 69

115

■ R507.6

■ R314

Smoke Alarms Carbon Monoxide Alarms

76

■ R322.3

Coastal High-Hazard Flood Zones

77

■ R324.4

Rooftop-Mounted Photovoltaic Systems

82

■ R324.6

Roof Access for Photovoltaic Solar Energy Systems

119

■

R507.7, R507.8, R507.9 Decking, Vertical and Lateral Support 122

■

Table R602.3(6) Alternate Stud Height

125

Tables R602.7(1), R602.7(2) Girder and Header Spans

129

Table R602.7.5 Lateral Support for Headers

133

Table R602.10.3(4) Seismic Adjustment Factors

135

73

■ R317.3

Fasteners in Treated Wood

Deck Joists

71

■ R315

■

■

■

85

■ R602.10.4.1

■ R324.6.2.2

Solar Panels near Emergency Escape and Rescue Openings

Mixing Bracing Methods 88

Mezzanine Area Limitation R325.6, R202 Habitable Attics

Method CS-PF—Continuously Sheathed Portal Frame

90

139

■ R602.10.6.5

92 ■

PART 3 Building Construction Chapters 4 through 10

137

■ R602.10.6.4

■ R325.3

■

Unvented Crawl Spaces

Decks 104

Maximum Stair Rise between Landings 64

■

98

■ R408.3

Area Wells for Emergency Escape and Rescue Doors

■ R311.7.3

■

Table R403.4 Crushed Stone Footings

94

Table R403.3(1) Insulation Requirements for Frost-Protected Footings 96

■

Method BV-WSP

141

Tables R603.3.1 and R603.3.1.1(2) Cold-Formed Steel Wall Construction

143

Section R610 Structural Insulated Panels

146

■ R703.2

Water-Resistive Barrier

149

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Contents  v

 ■ N1102.2.2

■ R703.3.1

Soffit Installation

■

Table R703.8.4(1) Airspace Requirements

154 ■

156

157

■

■ R802

Roof Framing

160

■

■ R802.1.5.4

Labeling 163 165

Unvented Attics

167

Tables R905.1.1(1) and R905.1.1(2) Underlayment Requirements for Photovoltaic Shingles

169

■ R905.17

Building Integrated Photovoltaic Panels

■

PART 4 Energy Conservation Chapter 11

171 173

194

N1103.3.2, N1103.3.3 Duct Sealing and Testing

197

N1103.3.6, N1103.3.7 Ducts Buried within Ceiling Insulation

199

N1106.3, N1106.4 Maximum Energy Rating Index

204

207

■

Access to Furnaces within Compartments

209

M1305.1.3.2 Appliances Installed in Pits

211

M1502.3.1 Dryer Exhaust Duct Termination

213

M1502.4.2 Concealed Dryer Exhaust Ducts

214

M1503 Domestic Cooking Exhaust Equipment

215

174

■

176

■

Definition of Building Thermal Envelope 178

■

M1503.6 Makeup Air for Kitchen Exhaust Systems 218

■

M1601.1.2 Underground Duct Systems

221

M1901 Ranges and Ovens

223

Table M2101.9 Hanger Spacing for PEX Tubing

225

M2101.10 Pressure Tests for Hydronic Piping

227

Definition of Air Barrier ■ N1101.6

N1101.6, Tables N1101.10.3(1) and N1101.10.3(2) Fenestration Definitions and U-Factors

179

■ N1102.1

Building Thermal Envelope for Log Homes 182 ■

Testing for Air Leakage

■ M1305.1.1

■

■ N1101.6

■

192

PART 5 Mechanical Chapters 12 through 23

■ R1005.8

Chimney Insulation Shield

Table N1102.2.6 Cold-Formed Steel Framing R-Values

Lighting 202

■ R806.5

■

190

■ N1104.1

■ R806.2

Minimum Vent Area

Mass Walls

■ N1102.4

■ R703.11.2

Vinyl Siding Installation Over Foam Plastic Sheathing

188

■ N1102.2.5

■ R703.8.4

Veneer Anchorage through Insulation

Reduction of Ceiling Insulation

151

Tables N1102.1.2 and N1102.1.4 Insulation and Fenestration Requirements 184

■

■

■

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

vi  Contents ■ P2801.6

■ M2103.2

Thermal Barrier for Radiant Floor Heating Systems

Plastic Pan for Gas-Fired Water Heaters 229

■ M2301

Solar Thermal Energy Systems

231

■

261

P2902.5.4, P2904.1 Backflow Protection for Fire Sprinkler Systems 263

■ P2903.5

Water Hammer Arrestors

PART 6 Fuel Gas Chapter 24 ■

■

■

265

■ P2906.6.1

233

G2406.2 Prohibited Locations for Appliances

234

G2411.2, G2411.3 Electrical Bonding of CSST

236

G2414.4.2, G2414.10.1 Schedule 10 Steel Gas Piping

239 241

■ G2420.5.1

Shutoff Valve Location

■ P2906.18.2

Joints between PVC and CPVC Piping

269

■ P3003.2

■ G2415.11

Protection against Corrosion

Saddle Tap Fittings on Water Distribution Piping 267

244

■ G2420.6

Support for Shutoff Valves in Tubing Systems 245

Prohibited Joints for Sanitary Drainage 271 ■ P3005.1.6

Reduction in Pipe Size

273

■ P3103.1

Vent Pipe Terminations

275

■ P3111

Combination Waste and Vent System

277

■ P3114.8

Prohibited Installations for Air Admittance Valves

279

■ G2442.2

Forced Air Furnace Duct Size

246

■ G2447.2

Commercial Cooking Appliances

PART 7 Plumbing Chapters 25 through 33

248

Garage Branch Circuits

250 252

■ P2602.1

Connections to Public Sewer or Private Sewage Disposal System

280

■ E3703.5

■ P2503.7

Air Testing of PEX Piping

PART 8 Electrical Chapters 34 through 43

281

■ E3901.2

Wall Space for Receptacle Distribution

283

■ E3901.3

Appliances on 15 Amp Circuits

285

■ E3901.9

254

Garage Receptacle Outlet Location

287

■ E3902.4

■ P2605

Sway Bracing for Drainage Piping

256

■ P2704

Slip Joint Connections

258

■ P2713.1

Bathtub Overflow

GFCI Protection for Crawl Space Lighting Outlets 289 ■ E3906.3

Nonmetallic-Sheathed Cable and Metal Boxes 291

260

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Contents  vii

 ■ E4101.3

Cord-and-Plug–Connected Appliances

■

293 ■

PART 9 Appendices Appendix A through T ■

■

295

Appendix Q Tiny Houses

296

Appendix R Light Straw-Clay Construction

300

Appendix S Strawbale Construction

302

Appendix T Solar-Ready Zone

307

Index309

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Preface

T

he purpose of Significant Changes to the International Residential Code®, 2018 Edition, is to familiarize building officials, fire officials, plans examiners, inspectors, design professionals, contractors, and others in the building construction industry with many of the important changes in the 2018 International Residential Code® (IRC®). This publication is designed to assist code users in identifying the specific code changes that have occurred and understanding the reasons behind the changes. It is also a valuable resource for jurisdictions in their code-adoption process. Only a portion of the code changes to the IRC are discussed in this book. The changes selected were identified for a number of reasons, including their frequency of application, special significance, or change in application. However, the importance of the changes not included is not to be diminished. Further information on all code changes can be found in the Complete Revision History to the 2018 I-Codes, available in 2018 from the International Code Council® (ICC®) online store http://shop.iccsafe .org. This code change resource provides  the published documentation for each successful code change ­contained in the 2018 IRC. Significant Changes to the International Residential Code, 2018 Edition, is organized into nine parts, each representing a distinct grouping of code topics. It is arranged to follow the general layout of the IRC, including code sections and section number format. The table of contents, in addition to providing guidance in the use of this publication, allows for a quick identification of those significant code changes that occur in the 2018 IRC. Throughout the book, each change is accompanied by a photograph or an illustration to assist and enhance the reader’s understanding of the specific change. A summary and a discussion of the significance of the change are also provided. Each code change is identified by type, be it an addition, modification, clarification, or deletion. The code change itself is presented in a legislative format similar to the style utilized for code-change proposals. Deleted code language is shown with a strikethrough, and new code text is indicated by underlining.

ix Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

x  Preface As a result, the actual 2018 code language is provided, as well as a comparison with the 2015 language, so the user can easily determine changes to the specific code text. As with any code-change text, Significant Changes to the International Residential Code, 2018 Edition, is best used as a companion to the 2018 IRC. Because only a limited discussion of each change is provided, the code itself should always be referenced in order to gain a more comprehensive understanding of the code change and its application. The commentary and opinions set forth in this text are those of the authors and do not necessarily represent the official position of ICC. In addition, they may not represent the views of any enforcing agency, as such agencies have the sole authority to render interpretations of the IRC. In many cases, the explanatory material is derived from the reasoning expressed by code-change proponents. Comments concerning this publication are encouraged and may be directed to ICC at [email protected].

About the International Residential Code® Building officials, design professionals, contractors and others involved in the field of residential building construction recognize the need for a modern, up-to-date residential code addressing the design and installation of building systems through both prescriptive and performance requirements. The International Residential Code® (IRC), 2018 Edition, is intended to meet these needs through model code regulations that safeguard the public health and safety in all communities, large and small. The IRC is kept up to date through ICC’s open code-development process. The provisions of the 2015 edition, along with those code changes approved through 2016, make up the 2018 edition. The IRC is one in a family of International Codes® published by ICC. This comprehensive residential code establishes minimum regulations for residential building systems by means of prescriptive and performance-­ related provisions. It is founded on broad-based principles that make possible the use of new materials and new building designs. The IRC is a comprehensive code containing provisions for building, energy conservation, mechanical, fuel gas, plumbing and electrical systems. The IRC is available for adoption and use by jurisdictions internationally. Its use within a governmental jurisdiction is intended to be accomplished through adoption by reference, in accordance with proceedings established by the jurisdiction’s laws.

Acknowledgments Grateful appreciation is due to many ICC staff members, including those in Product Development, Publishing, Marketing, and Technical Services, for their generous assistance in the preparation of this publication. Fred Grable, P.E., ICC Senior Staff Engineer, shared his expertise and provided Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Preface  xi



commentary on the plumbing provisions. Gregg Gress, ICC Senior Technical Staff, provided welcome assistance on the mechanical and fuel gas provisions. All contributed to the accuracy and quality of the finished product.

About the Authors Stephen A. Van Note, CBO International Code Council Managing Director, Product Development Stephen A. Van Note is the Managing Director of Product Development for the International Code Council (ICC), where he is responsible for developing technical resource materials in support of the International Codes. His role also includes the management, review, and technical editing of publications developed by ICC staff members and other expert authors. He has authored a number of ICC support publications, including Residential Code Essentials and Inspector Skills. In addition, Steve develops and presents International Residential Code seminars nationally. He has over 40 years of experience in the construction and building code arena. Prior to joining ICC in 2006, Steve was a building official for Linn County, Iowa. Prior to his 15 years at Linn County, he was a carpenter and construction project manager for residential, commercial, and industrial buildings. A certified building official and plans examiner, Steve also holds certifications in several inspection categories. Sandra Hyde, P.E. International Code Council Senior Staff Engineer, Product Development Sandra Hyde is a Senior Staff Engineer with the International Code ­Council (ICC), where, as part of the Product Development team, she develops technical resource materials in support of the structural provisions of the International Residential, Building, and Existing Building Codes. Her role also includes review and technical editing of publications authored by ICC and engineering associations, and the presentation of technical seminars on the IRC and IBC structural provisions. She has authored and reviewed support publications, including Significant Changes to the International Building Code, Special Inspection Manual, and, in conjunction with APA, Guide to the IRC Wall Bracing Provisions. Prior to joining ICC in 2010, Sandra worked in manufacturing and research of engineered wood products. She is a Registered Civil Engineer in Idaho and California.

About the International Code Council® The International Code Council is a member-focused association. It is dedicated to developing model codes and standards used in the design, build, and compliance process to construct safe, sustainable, affordable, Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

xii  Preface and resilient structures. Most U.S. communities and many global markets choose the International Codes® (I-Codes®). ICC Evaluation Service (ICCES) is the industry leader in performing technical evaluations for code compliance, fostering safe and sustainable design and construction. ICC Headquarters: 500 New Jersey Avenue, NW, 6th Floor Washington, DC 20001 Regional Offices: Birmingham, AL; Chicago, IL; Los Angeles, CA 1-888-422-7233 (ICC-SAFE) www.iccsafe.org

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

PART

1

Administration Chapters 1 and 2

■ Chapter 1 Scope and Administration ■ Chapter 2 Definitions

T

R101.2 Scope R104.11

he administration part of the International Residential Code (IRC) covers the general scope, purpose, applicability, and other administrative issues related to the regulation of residential buildings by building safety departments. The administrative provisions establish the responsibilities and duties of the various parties involved in residential construction and the applicability of the technical provisions within a legal, regulatory, and code-enforcement arena. Section R101.2 establishes the criteria for buildings that are regulated by the IRC. Buildings beyond the scope of Section R101.2 are regulated by the International Building Code (IBC). The remaining topics in the administration provisions of Chapter 1 include the establishment of the building safety department, duties of the building official, permits, construction documents, and inspections. The definitions contained within the IRC are intended to reflect the special meaning of such terms within the scope of the code. As terms can often have multiple meanings within their ordinary day-to-day use or within the various disciplines of the construction industry, it is important that their meanings within the context of the IRC be understood. Most definitions used throughout the IRC are found in Chapter 2, but additional definitions specific to the applicable topics are found in the energy provisions of Chapter 11, the fuel gas provisions of Chapter 24, and the electrical provisions of Chapter 35.  ■

Alternative Materials and Methods of Construction R105.1, R110.1, R202 Change of Occupancy R202 Definition of Access R202 Definition of Crawl Space R202 Definition of Carbon Monoxide Alarm R202 Definition of Fenestration R202 Definition of Solar Energy System

1

1 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

2  Part 1  ■ Administration

R101.2

Change Type: Modification

Scope

Change Summary:  All instances where the International Building Code (IBC) permits construction under the IRC are now listed in the exception to the scope of the IRC. 2018 Code:  R101.2 Scope.  The provisions of the International ­Residential Code for One- and Two-family Dwellings this code shall ­apply to the construction, alteration, movement, enlargement, replacement, ­repair, equipment, use and occupancy, location, removal and demolition of detached one- and two-family dwellings and townhouses not more than three stories above grade plane in height with a separate means of egress and their accessory structures not more than three stories above grade plane in height. Exceptions:  The following shall be permitted to be constructed in accordance with this code where provided with a residential fire sprinkler system complying with Section P2904: 1. Live/work units located in townhouses and complying with the requirements of Section 419 of the International Building Code shall be permitted to be constructed in accordance with the International Residential Code for One- and Two-Family Dwellings. Fire suppression required by Section 419.5 of the International Building Code where constructed under the International Residential Code for One- and Two-family Dwellings shall conform to Section P2904.



2. Owner-occupied lodging houses with five or fewer guestrooms shall be permitted to be constructed in accordance with the International Residential Code for One- and Twofamily Dwellings where equipped with a fire sprinkler system in accordance with Section P2904.

Christian Delbert/Shutterstock.com



Bed and breakfast Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R101.2  ■ Scope  



3. A care facility with five or fewer persons receiving custodial care within a dwelling unit.



4. A care facility with five or fewer persons receiving medical care within a dwelling unit.



5. A care facility for five or fewer persons receiving care that are within a single-family dwelling.

Change Significance: The IBC applies to the construction, ­alteration, relocation, enlargement, replacement, repair, equipment, use and ­occupancy, location, maintenance, removal and demolition of every building or structure. That is stated in the scope of the IBC. It ­generally applies to all buildings. However, the exception to the scope says ­detached one- and two-family dwellings and townhouses not more than three ­stories above grade plane shall comply with the International Residential Code (IRC). This exception to the IBC scope matches the scope of the IRC, bringing the two codes into alignment. There are also provisions where the two codes correlate for a limited number of uses. For example, requirements for live/work units and lodging houses have previously appeared in both codes. The 2018 IRC has updated the exceptions to the scope to include all of those uses recognized in the IBC as permitting construction under the IRC. The three uses new to the IRC are care facilities for five or fewer persons receiving various levels of care. The 2009 editions of the IBC and IRC introduced provisions embracing the concept of live/work units. These combine a residential dwelling unit with a small business use. A live/work unit is defined in the IBC as a dwelling unit or sleeping unit in which a significant portion of the space includes a nonresidential use that is operated by the tenant. The code limits the number of employees for the business to five and limits the area of the unit. Live/work units are part of recent trends in community development reminiscent of the early 1900s where neighborhoods included various service businesses. The new trend is often referred to as “Traditional Neighborhood Design.” The intent was to reduce requirements for this traditional use and it is not considered a mixed occupancy. This is the one instance where the IBC does not send the code user to the IRC as an approved method of construction. Rather the IRC permits live/work units in townhouses under the exceptions to its scope, but sends the user to the IBC for the details. Owner-occupied lodging houses with five or fewer guestrooms were added to the exceptions to the scope of the IRC in the 2012 edition. The intent was to allow construction of small bed-and-breakfast operations under the IRC provisions that were perceived as less restrictive than those of the IBC. The IBC, on the other hand, did not state that the IRC could be used for construction of lodging houses. That language first appeared in the 2015 IBC in Section 310.5.2 and permitted owner-occupied lodging houses with five or fewer guestrooms to be constructed under the IRC. Small bed-and-breakfast operations are considered similar to and compatible with one- and two-family dwellings and townhouses regulated by the residential code. Three additional items have been added to the exception of the IRC scope to correlate with the corresponding language in Chapter 3 of the IBC. This change intends to complete cross-references between the two codes and alerts IRC code users to the corresponding language in the IBC. R101.2 continues Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

3

4  Part 1  ■ Administration R101.2 continued

Chapter 3 of the IBC describes the various uses of buildings and their assignment into an occupancy classification. The IRC does not classify buildings into occupancy groups, but there are certain classifications within the IBC that are limited in the number of occupants and are considered to have a similar level of hazard as single-family dwellings regulated by the IRC. New to the 2018 IRC, as exceptions to the scope, are uses related to care facilities. In all cases, the number of persons being cared for cannot exceed five. See Table 1-1 for the corresponding sections in the IRC and IBC.

Table 1-1   Exceptions to the Scope in the IRC and Corresponding Location in the IBC First Appeared in IRC

2015 IBC Section

2018 IBC Section

IRC Description

IBC Occupancy Group

IBC Reference to IRC

2009

419

419

Live/work units

R-2

No

2012

310.5.2

310.4.2

Owner-occupied lodging houses with five or fewer guestrooms

R-3

Yes

2018

308.3.4

308.2.4

R-3

Yes

308.6.4

308.5.4

A care facility with five or fewer persons receiving custodial care within a dwelling unit.

2018

308.4.2

308.3.2

A care facility with five or fewer persons receiving medical care within a dwelling unit.

R-3

Yes

2018

310.5.1

310.4.1

A care facility for five or fewer persons receiving care within a single-family dwelling.

R-3

Yes

The list of exceptions to the scope of the IRC has also been reorganized and edited for clarification. The previous reference in the IRC to the “International Residential Code” has been replaced with “this code,” which is consistent with provisions throughout the ICC family of codes. All five items under the exception are special uses permitted in the IRC that have their basis in the IBC and all specifically require a residential fire sprinkler system complying with IRC Section P2904. That information now appears at the top of the list to apply to all five items, rather than listing the same requirement for each item. Although an automatic fire sprinkler system is required for all new dwellings and townhouses under the IRC, state and local amendments to the code have removed sprinkler requirements in many jurisdictions. All of the corresponding provisions in the IBC require fire sprinkler systems. In addition, the three sections in Chapter 3 of the IBC specifically require an automatic sprinkler system in accordance with NFPA 13D or IRC Section P2904 when permitting construction under the IRC. If the sprinkler reference did not appear in the IRC list, there was concern that code users would not be familiar with the correlating IBC provisions that required sprinklers.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R104.11  ■  Alternative Materials  

Change Type: Modification

R104.11

Change Summary:  The process to gain compliance through the alternative materials and methods provisions now requires an application by the owner or owner’s authorized agent and gives authority to the building official to approve based on a prescriptive list of equivalencies.

Alternative Materials and Methods of Construction

2018 Code:  R104.11 Alternative materials, design and methods of construction and equipment.  The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An The building official shall have the authority to approve an alternative material, d ­ esign or method of construction shall be approved upon ­application of the owner or the owner’s authorized agent. where the The building official shall first finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, not less than the equivalent of that prescribed in this code in quality, strength, e­ ffectiveness, fire resistance, durability and safety. Compliance with the specific ­performance-based provisions of the International Codes shall be an alternative to the specific requirements of this code. Where the alternative material, design or method of construction is not approved, the building official shall respond in writing, stating the reasons why the alternative was not approved. Change Significance:  One of the most important provisions in the code, the language for alternative materials, design and methods of ­construction is explicit in its meaning to not exclude any material, design or method of construction. This provides needed flexibility and recognizes constantly evolving technology and new materials in the world of construction. Unlike many other International Codes (I-Codes), the IRC is primarily a prescriptive code, meaning it usually sets out very specific rules to follow in gaining compliance. It does also recognize performance provisions that require systems or components to function in a certain way to meet the desired level of safety or performance without ­specifying the methods to achieve that goal. In terms of structural requirements, performance is typically achieved through engineering. Testing of materials and systems is another way to demonstrate an adequate level of performance. The alternative materials and methods provisions are performance-driven and often require some documentation to demonstrate that the method meets the intent of the specific code provisions. Reports issued by the International Code Council’s Evaluation Service (ICC-ES) are valuable resources in verifying performance equal to the code requirements. In the absence of ICC-ES evaluation reports and where insufficient data or documentation exists, the building official may require that tests be performed by an approved agency to demonstrate compliance with the code. Also, compliance with the specific performance-based provisions of the referenced I-Codes satisfies the IRC requirements. With the exception of one added sentence at the end of Section R104.11, very little has changed in this section of the IRC since its inception. The building official has always had an obligation, as instructed by R104.11 continues

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

5

6  Part 1  ■ Administration the code, to approve such alternatives where he or she found that the proposed material or construction met the intent of the IRC and was equivalent to the code provisions. In the 2015 IRC, a new sentence appeared requiring the building official to give the reason in writing for disapproval of a proposed alternative. In the 2018 code, the process for alternative methods and materials has been formalized somewhat. The code now requires an application by the owner or the owner’s authorized agent for consideration by the building official. The wording has changed slightly from the building official “shall approve” to the building official “shall have the authority to approve.” Also, the basis for approval is now more specific, picking up a list of criteria from the corresponding section of the IBC for determining equivalency. Previously the IRC required a determination that the alternative was at least the equivalent to that prescribed by the code, and now adds to that “in quality, strength, effectiveness, fire resistance, durability and safety.” The changes are minor and the procedures for determining acceptance of alternative materials and methods within the individual jurisdictions will likely remain the same.

Mona Makela/Shutterstock.com

R104.11 continued

Andrew McDonough/Shutterstock.com

A new house constructed of alternative materials

An alternative method for framing a house

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R105.1, R110.1, R202  ■  Change of Occupancy  

R105.1, R110.1, R202

Change Type: Clarification Change Summary:  A definition for “Change of Occupancy” has been added and the requirement for a certificate of occupancy when there is a change of occupancy or use has been clarified. 2018 Code:  R105.1 Required.  Any owner or owner’s authorized agent who intends to construct, enlarge, alter, repair, move or demolish or a change the of occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove, convert or replace any electrical, gas, ­mechanical or plumbing system, the installation of which is regulated by this code, or to cause any such work to be performed, shall first make ­application to the building official and obtain the required permit.

Change of Occupancy

R110.1 Use and occupancy.  A building or structure shall not be used or occupied, and a change in the existing use or of occupancy ­classification or change of use of a building or structure or portion thereof shall not be made, until the building official has issued a certificate of occupancy therefor as provided herein. Issuance of a certificate of occupancy shall not be construed as an approval of a violation of the provisions of this code or of other ordinances of the jurisdiction. Certificates presuming to give authority to violate or cancel the provisions of this code or other ­ordinances of the jurisdiction shall not be valid. Exceptions:

1. Certificates of occupancy are not required for work exempt from permits under Section R105.2.



2. Accessory buildings or structures.

Arina P Habich/Shutterstock.com

R105.1, R110.1, R202 continues

Converting a townhouse from a dwelling unit to a live/work unit is considered a change of use Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

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8  Part 1  ■ Administration R105.1, R110.1, R202 continued

R202 DEFINITIONS CHANGE OF OCCUPANCY.  A change in the use of a building or a portion of a building that involves a change in the application of the ­requirements of this code. Change Significance:  Issuance of a certificate of occupancy indicates that construction work has passed final inspection and the dwelling unit, or in the case of an addition, the portion of the dwelling unit c­ overed by the permit, can be occupied. This is fairly straightforward in the IRC where there is no occupancy group classification or type of construction designation. From its inception, the IRC has also contained language regarding a change in occupancy or change in use. Such a change required a permit before beginning construction and required a certificate of occupancy ­before occupancy of the building. Although these are very important tools in the International Building Code (IBC), where changes of occupancy classification or a change in use that increases the hazard occur frequently, these provisions have had limited if any application in the IRC. To many code users, change of occupancy or use meant that it was changing from an IRC-regulated building to an IBC-regulated building, or vice versa. For example, it was never the intent that remodeling of an existing singlefamily dwelling that increased the area of habitable space or the number of bedrooms would be considered a change of occupancy or use; it’s still a single-family dwelling. However, even without a change of use ­designation, the results may be exactly the same. Construction work still requires a permit and, depending on the procedures of the jurisdiction, may require a certificate of occupancy before occupying portions of the dwelling covered by the permit, even though the use remains the same. The new definition for “Change of Occupancy” and editorial changes to Section R110.1, Use and Occupancy, intend to clarify the application of a change of use or a change of occupancy in the IRC. According to the new definition, it is a change in the application of the requirements of the IRC. The intent is that “change in application” applies only to the special-use buildings in the exception to the scope of the IRC. The five uses listed in the exception to Section R101.2 also occur in the IBC. For an example of a change in application, a one- or two-family dwelling constructed under the IRC and subsequently adapted to become an owner-occupied lodging house (a bed and breakfast) would be considered a change of occupancy. A townhouse d ­ welling unit that was changing to a live/work unit would also be considered a change of occupancy. The new definition would also apply to the three new uses in the exception to the scope of the IRC related to care facilities with five or fewer persons receiving care (see the changes and discussion under Section R101.2 in this publication). Because all of these uses are considered low hazard and are now allowed to be constructed under the IRC, the change of occupancy will not typically impose any additional requirements, unless the existing building does not have an automatic sprinkler system. All five special uses specifically require sprinkler s­ystems because of a concern that local amendments may have removed the mandatory sprinkler requirements in IRC Section R313. In addition, live/work units must comply with the provisions in IBC Section 419.

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Significant Changes to the IRC 2018 Edition

Change Type:­ 

R202  ■  Definition of Access  

R202

Clarification

Change Summary:  New definitions for “access” and “ready access” apply to equipment and devices that must be reached for service or replacement.

Definition of Access

2018 Code:  R202 DEFINITIONS ACCESSIBLE.  Signifies access that requires the removal of an access panel or similar removable obstruction. ACCESS (TO)  That which enables a device, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction. ACCESSIBLE, READILY.  Signifies access without the necessity for ­removing a panel or similar obstruction. READY ACCESS (TO)  That which enables a device, appliance or equipment to be directly reached, without requiring the removal or movement of any panel, door or similar obstruction. CLEANOUT.  An accessible opening in the drainage system used for the removal of possible obstruction and located to allow for access. FIXTURE FITTING. Supply fitting.  A fitting that controls the volume or directional flow or both of water and that is either attached to or accessible accessed from a fixture or is used with an open or atmospheric discharge. R202 continues

Door or removable access panel

Access to whirlpool pump

Whirlpool tub

© International Code Council

Pump motor

© International Code Council

Cold water valve

Ready access to cold water valve of water heater

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

9

10  Part 1  ■ Administration R202 continued

Change Significance:  The word “accessible” appears often in both the IRC and the IBC. In each case, it can have a very different meaning depending on the context and the provision for which it applies. “Accessible” in  the IBC is defined as a site, building, facility or portion thereof that complies with Chapter 11, which contains provisions to control the design and construction of facilities for accessibility and usability for individuals with disabilities. For users of the IBC, the meaning of “accessible” or “accessibility” is well understood in the context of Chapter 11 and the various chapters referencing Chapter 11 for accessibility requirements. Both the IRC and IBC use the word “accessible” for other meanings as well; for example, work is required to be accessible for inspection; portions of a building or a device must be accessible to fire departments; devices must be accessible for service. Unrelated to provisions for persons with disabilities, these provisions use the common dictionary meaning of “accessible.” Previously in the IRC, “accessible” referred to access that required the removal of an access panel or similar removable obstruction. “Readily accessible” referred to access without having to remove a panel or obstruction. These terms have been used throughout the IRC for providing access to equipment or spaces for inspection, repair or replacement. However, Sections R320 and R321.3 reference accessibility and accessible as relating to IBC Chapter 11 for accessibility for individuals with disabilities. To clear up confusion in the IRC, the defined terms have been changed to “access to” and “ready access to” for accessing equipment, devices and spaces. This removes the conflict between defined terms appearing in the IRC and IBC with different meanings. It is important to note that “accessible” has different definitions in the energy provisions in IRC Chapter 11 and the electrical provisions in Chapter 35.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R202  ■  Definition of Crawl Space  

11

Change Type: Addition

R202

Change Summary:  A definition for crawl space has been added to the IRC.

Definition of Crawl Space

2018 Code:  R202 DEFINITIONS CRAWL SPACE.  An underfloor space that is not a basement.

iStock.com/Double_Vision

Change Significance:  The term “crawl space” has been undefined in the IRC, even though it is used often throughout the code and is a common term in residential construction. For example, the footing tables in Section R403 are based on one of three types of foundations: basement, crawl space, or slab-on-grade. In most cases in the IRC, “crawl space” has been interchangeable with “underfloor space.” Most code users and builders would say they know a crawl space when they see one. Generally, use of the term in the building trades refers to a space within foundation walls with a height less than that of a basement or less than that required to stand upright. Merriam Webster defines it as “a shallow unfinished space beneath the first floor or under the roof of a building especially for access to plumbing or wiring.” Other definitions describe it as an area in a building that is accessible by crawling and has a clearance less than human height, for access to plumbing, wiring, storage or other similar uses. Placing a new definition in the IRC was based on the fact that there was no definition in the IRC even though the term is used often in the code, and because it was necessary to distinguish crawl spaces from basements. In the 2018 IRC, a crawl space is an underfloor space that is not a basement.

Crawl space Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

12  Part 1  ■ Administration

R202

Change Type: Addition

Definition of Carbon Monoxide Alarm

Change Summary:  New definitions differentiate carbon monoxide alarm from carbon monoxide detector. 2018 Code:  R202 DEFINITIONS CARBON MONOXIDE ALARM.  A single- or multiple-station alarm i­ ntended to detect carbon monoxide gas and alert occupants by a distinct audible signal. It incorporates a sensor, control components, and an alarm notification appliance in a single unit. CARBON MONOXIDE DETECTOR.  A device with an integral sensor to detect carbon monoxide gas and transmit an alarm signal to a connected alarm control unit.

Danny E Hooks/Shutterstock.com

Change Significance:  Provisions for carbon monoxide alarms first appeared in the 2009 edition of the IRC, and they have since been required in dwelling units containing fuel-fired appliances or having an attached garage. They were introduced in the code to reduce accidental injuries and deaths from carbon monoxide poisoning. A carbon monoxide alarm is a self-contained device that provides both carbon monoxide

Carbon monoxide alarm Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R202  ■  Definition of Carbon Monoxide Alarm  

detection and an alarm-sounding appliance. Carbon monoxide alarms must be listed as conforming to UL 217. Beginning with the 2012 IRC, the code has offered an alternative to self-contained carbon monoxide alarms. A household carbon monoxide detection system installed in accordance with NFPA 720 Standard for the Installation of Carbon Monoxide (CO) Detection and Warning Equipment is considered equivalent to the standalone carbon monoxide alarm provisions and satisfies the requirements for protection against carbon monoxide poisoning. A household carbon monoxide detection system typically has separate devices for carbon monoxide detection and alarm annunciation. It is similar in design to a household fire alarm system complying with the IRC smoke alarm provisions and NFPA 72. For such a detection system, carbon monoxide detectors must be listed in accordance with UL 2075. New definitions clarify the difference between carbon monoxide alarms and carbon monoxide detectors. Many code users, builders, and the public use these terms interchangeably. Likewise, “detector” is often used in published sources and found in online information, when the correct term is “alarm.” The self-contained carbon monoxide alarm is by far the more common installation in dwelling units regulated by the IRC. The new definitions intend to improve code compliance and understanding for those not familiar with the two types of carbon monoxide devices.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

13

14  Part 1  ■ Administration

R202

Change Type: Clarification

Definition of Fenestration

Change Summary:  The definition for fenestration has been modified to encompass a new definition for vertical fenestration and the modified definition for skylights and sloped glazing. 2018 Code:  R202 DEFINITIONS FENESTRATION.  Skylights, Products classified as either vertical f­enestration or skylights and sloped glazing, installed in such a manner as to preserve the weather resistant barrier of the wall or roof windows, vertical windows (whether fixed in which they are installed. Fenestration includes products with glass or moveable); opaque doors; glazed doors; glass block; and combination opaque and glazed doors other transparent or translucent materials. For the definition applicable in Chapter 11, see Section N1101.6. FENESTRATION, VERTICAL.  Windows that are fixed or moveable, opaque doors, glazed doors, glazed block and combination opaque and glazed doors installed in a wall at less than 15 degrees from vertical. For the definition applicable in Chapter 11, see Section N1101.6. SKYLIGHTS AND SLOPED GLAZING.  Glass or other transparent or translucent glazing material installed at a slope of 15 degrees (0.26 rad) or more from vertical. Glazing materials in skylights, including unit Unit skylights, tubular daylighting devices, and glazing materials in solariums, sunrooms, roofs and sloped walls are included in this definition.

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For the definition applicable in Chapter 11, see Section N1101.6.

Skylights Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R202  ■  Definition of Fenestration  

Change Significance:  The IRC provisions for skylights and sloped glazing are found in Section R308.6. They are primarily concerned with the type of glazing materials used and providing safety screens below the glazing under limited conditions. For residential buildings constructed under the IRC, screens are rarely required or utilized. Unit skylights and ­ tubular daylighting devices require testing and labeling in ­compliance with the requirements of AAMA/WDMA/CSA 101/I.S.2/ A440. By ­definition skylights are considered fenestration. Requirements for exterior windows and doors installed in walls are covered in Section R609 and are concerned with resistance to wind loads and weather resistance. These are considered vertical fenestration. All fenestration is carefully considered for energy conservation in both the prescriptive and performance-based compliance paths in Chapter 11. Those provisions are extracted from the residential energy provisions of the International Energy Conservation Code (IECC). IRC definitions for vertical fenestration and skylights appear in both Section R202 and N1101.6 of the energy provisions. Revisions to the 2018 IRC clarify that fenestration is a general term that includes both vertical fenestration and skylights and sloped glazing. In the energy provisions, vertical fenestration and skylights are sub-definitions placed directly below fenestration. A new definition for vertical fenestration has been added to Section R202 and definitions for fenestration and skylights and sloped glazing have been revised. The changes clarify what fenestration is and what specific products it includes. Although there is a general alignment of meanings of fenestration in IRC Sections R202 and N1101.6, and the residential provisions of the IECC, there are also significant differences related to the slope of the glazing. The energy provisions define vertical fenestration as glazing materials at a slope of at least 60 degrees from horizontal (30 degrees from vertical), and skylights as glazing material installed at a slope of less than 60 degrees from horizontal. The dividing point in IRC Section R202 is 15 degrees rather than 30 degrees from vertical. As has been the case in previous editions, skylights and sloped glazing are defined as glazing material installed at a slope of at least 15 degrees from vertical (85 degrees from horizontal). The new definition for vertical fenestration is consistent and is defined as glazing installed at a slope of less than 15 degrees from vertical. In effect, the maximum slope of a skylight under the energy provisions is about 21/12. Under Section R202 provisions, the determining slope is steeper, at about 24/12. The American Architectural Manufacturers Association (AAMA) favors the steeper pitch. The code change proponent stated that the design of products to be weather-resistant, particularly with regards to water penetration and snow load, is quite different for products installed at any slope at all in comparison to products installed in a completely vertical position. Consensus was that 15 degrees from vertical has been and should be the accepted threshold for this distinction in Section R202.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

15

16  Part 1  ■ Administration

R202

Change Type: Clarification

Definition of Solar Energy System

Change Summary:  New definitions related to solar energy systems help to clarify the related provisions in Chapters 3 and 9. 2018 Code:  R202 DEFINITIONS SOLAR ENERGY SYSTEM.  A system that converts solar radiation to usable energy, including photovoltaic panel system and solar thermal system. SOLAR THERMAL COLLECTOR.  Components in a solar thermal system that collect and convert solar radiation to thermal energy. SOLAR THERMAL SYSTEM.  A system that converts solar radiation to thermal energy for use in heating or cooling.

© International Code Council

Change Significance:  Solar energy systems, particularly photovoltaic (PV) systems, have proliferated in the past decade and are now commonly seen on rooftops of residential buildings in some areas of the country. In keeping up with the evolving technology and the popularity of these energy-saving installations, the solar energy provisions

New defined terms for solar thermal systems and collectors are from ICC 900/SRCC 300 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R202  ■  Definition of Solar Energy System  

in Chapters  3 and 9 have been revised and expanded in the 2018 IRC, and are covered later in this publication. The changes reflect an effort to consolidate and organize all the requirements in an easy-to-use format to assist the user in understanding the applicable requirements—fire, electrical, structural, plumbing and mechanical—related to solar thermal and PV systems. In addition, there are new provisions for roof access and pathways for firefighters related to rooftop-mounted PV solar energy systems. Similarly, new language ensures that a path is maintained for emergency escape and rescue openings above a roof containing PV panels and modules. To assist in understanding and using the new solar energy provisions, new definitions have been added to the IRC. The new definition for solar energy system clarifies that there are two types of systems for converting solar radiation to usable energy: PV panel systems and solar thermal systems. The new terms “solar thermal collector” and “solar thermal system” are from ICC 900/SRCC 300-15, Solar Thermal System Standard. The standard establishes minimum criteria for the design and installation of solar thermal systems and represents an update to Solar Rating and Certification Corporation (SRCC) Standard 300. Solar thermal energy systems are covered in Section M2301 of the IRC mechanical provisions. Information on solar water-heating systems is found in Sections P2802 and P2902.5.5 of the plumbing provisions.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

17

PART

2

Building Planning Chapter 3

■ Chapter 3

Building Planning

Ta b l e R 3 0 1 . 2 ( 1 ) Climatic and Geographic Design Criteria

C

hapter 3 includes the bulk of the nonstructural provisions, including the location on the lot, fire-resistant construction, light and ventilation, emergency escape and rescue, fire protection, safety glazing, fall protection, and many other provisions aimed at protecting the health, safety, and welfare of the public. In addition to such health and life-safety issues, Chapter 3 provides the overall structural design criteria for residential buildings regulated by the IRC. Section R301 addresses live loads, dead loads, and environmental loads such as wind, seismic, and snow.  ■

R301.2.2.1 Seismic Design Category R301.2.2.6 Irregular Buildings R302.1 Exterior Walls R302.2 Townhouse Separation R302.3 Two-Family Dwelling Separation R302.4.2 Membrane Penetrations R302.5 Dwelling-Garage Opening Protection R302.10 Insulation Flame Spread R302.13 Fire Protection of Floors above Crawl Spaces

18 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

  ■      19

Significant Changes to the IBC 2018 Edition

R308.4.2

R314

Glazing Adjacent to Doors

Smoke Alarms

R308.4.4

R315

Glazing in Guards and Railings

Carbon Monoxide Alarms

R308.4.7

R317.3

Glazing Adjacent to the Bottom Stair Landing

Fasteners in Treated Wood

R310.1 Emergency Escape and Rescue Openings R310.3 Area Wells for Emergency Escape and Rescue Doors R311.7.1, R311.7.8 Handrail Projection R311.7.3

R322.3 Coastal High-Hazard Flood Zones R324.4 Rooftop-Mounted Photovoltaic Systems R324.6 Roof Access for Photovoltaic Solar Energy Systems R324.6.2.2

Maximum Stair Rise between Landings

Solar Panels near Emergency Escape and Rescue Openings

R311.7.5.3

R325.3

Stair Nosings

Mezzanine Area Limitation

R311.7.11, R311.7.12

R325.6, R202

Alternating Tread Devices and Ships Ladders

Habitable Attics

R312.1 Guards

19 Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

20  Part 2  ■  Building Planning

Table R301.2(1)

Change Type: Modification Change Summary:  Jurisdictions will now include variables for Manual J assessments with other climatic and geographic design criteria available in the building department’s Table R301.2(1) Design Criteria.

Climatic and Geographic Design Criteria

2018 Code: 

TABLE R301.2(1)  Climatic and Geographic Design Criteria Wind Design Ground Snow Loado

Topographic effectsk

Speedd (mph)

Subject to Damage From Weatheringa

 

Frost line depthb

Winter Design Tempe

Termitec

 

 

Special wind regionl

Ice Barrier Underlayment Requiredh

 

Seismic Design Categoryf

Wind-borne debris zonem

Flood Hazardg

 

Air Freezing Indexi

 

Mean Annual Tempj

 

 

Manual J Design Criterian

Elevation

Heating Temperature Difference

Latitude

Winter Heating

Cooling Temperature Difference

Wind Velocity Heating

Summer Cooling

Wind Velocity Cooling

Altitude Correction Factor

Coincident Wet Bulb

Indoor Design Temperature

Daily Range

Design Temperature Cooling

Winter Humidity

Summer Humidity

For SI: 1 pound per square foot = 0.0479 kPa, 1 mile per hour = 0.447 m/s.

(no changes to footnotes a through m) n. The jurisdiction shall fill in these sections of the table to establish the design criteria using Table 1a or 1b from ACCA Manual J or established criteria determined by the jurisdiction. o. The jurisdiction shall fill in this section of the table using the Ground Snow Loads in Figure R301.2(6).

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

Table R301.2(1)  ■  Climatic and Geographic Design  

Change Significance:  Manual J – Residential Load Calculation is a standard published by the Air Conditioning Contractors of America (ACCA) and is used for sizing heating and cooling (HVAC) systems in residential buildings based on the climate of the particular geographic location. The requirement for a Manual J assessment or engineered equivalent has been in the IRC for several editions, but the code has not required the jurisdiction to determine local design criteria for consistent application of the standard. As part of the model code adoption process, the IRC now directs the jurisdiction to establish the applicable design criteria and fill in the portions of Table R301.2(1) related to Manual J and sizing of HVAC systems. This will assist design professionals and contractors in making HVAC load calculations for projects within the jurisdiction and encourage consistent and accurate application of the code and Manual J. A jurisdiction may use Table 1a or 1b from ACCA Manual J or consider local conditions to determine the design criteria. The new code provision keeps design options open by allowing a jurisdiction to set local values based on local data. When there is no local data available or the jurisdiction covers a large area, such as a county building department, Manual J may be used to establish criteria. ACCA Manual J contains two simplified methods for determining the total amount of heat lost through the exterior of a home during the cool months, and the total amount of heat gained through the exterior of a home during the warm months. The first is the whole house or block load calculation. Whole house load calculations are commonly used to determine the correct HVAC equipment size and match-up when replacing the HVAC system in an existing home.

iStock.com/BanksPhotos

R301.2(1) continues

HVAC system duct work

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

21

22  Part 2  ■  Building Planning R301.2(1) continued

The second load calculation includes a room-by-room calculation method that allows the designer to determine the heating and cooling loads for each individual room, the required capacity of heating and cooling equipment, and a means to estimate the airflow requirements to determine minimum individual duct sizes as well as the size and layout of the duct system. This method is often used for new construction.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R301.2.2.1  ■  Seismic Design Category  

Change Type:  Modification

R301.2.2.1

Change Summary:  A new alternative seismic map allows potentially a lower seismic design category based on determination of soil type.

Seismic Design Category

2018 Code:  R301.2.2.1 Determination of seismic design category.  Buildings shall be assigned a seismic design category in accordance with Figure R301.2(2). R301.2.2.1 continues 110°

100°

50

120°

83

50

33

50 125

83

17

67

33

45°

67

50

33

50

125

17

125

40° 67

83

125

17

125

12 5

17

35° 33

33

Map prepared by U.S. Geological Survey in collaboration with the Federal Emergency Management Agency (FEMA)-funded Building Seismic Safety Council’s (BSSC) Code Resource Support Committee (CRSC).

30°

© International Code Council

Building Seismic Safety Council, 2015, NEHRP Recommended Seismic Provisions for New Buildings and Other Structures: FEMA P-1050, Federal Emergency Management Agency, Washington, DC. Petersen, M.D., Moschetti, M.P., Powers, P.M., Mueller, C.S., Haller, K.M., Frankel, A.D., Zeng, Y., Rezaeian, S., Harmsen, S.C., Boyd, O.L., Field, E.H., Chen, R., Rukstales, K.S., Luco, N., Wheeler, R.L., Williams, R.A., and Olsen, A.H., 2014, Documentation for the 2014 Update of the United States National Seismic Hazard Maps: U.S. Geological Survey Open-File Report 2014-1091, 243 p. Seyhan, E. and Stewart, J.P., 2014, Semi-Empirical Nonlinear Site Amplification from NGA-West2 Data and Simulations. Earthquake Spectra, Vol. 30, No. 3, pp. 1241–1256.

33

REFERENCES

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

23

24  Part 2  ■  Building Planning R301.2.2.1 continued 90°

80°

70°

50°

45°

33

33

17 17

40°

17

17

33

17

35° 17

50 33

33

Explanation

17

%g 125

17

100

0 100

100 0

200

300

400

Seismic design category E

83

D2

67

D1

50

D0

33

C

17

B

0

A

500 Miles

100 200 300 400 500 Kilometers

30°

25°

© International Code Council

50

50

5 12 7 6

Seismic Design Categories

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R301.2.2.1  ■  Seismic Design Category  

R301.2.2.1.1 Alternate determination of seismic design category.  The seismic design categories and corresponding short-period design spectral response accelerations, SDS, shown in Figure R301.2(2) are based on soil Site Class D, used as an assumed default, as defined in Section 1613.2.2 of the International Building Code. If soil conditions are other than determined by the building official to be Site Class A, B, or D, the seismic design category and short-period design spectral response accelerations, SDS, for a site can shall be allowed to R301.2.2.1 continues

110°

100°

50

120°

33

50

50

17

67

33

45°

67

125

50

33

50

83

17

83

40° 67 17

83

33

5 12

17 33

35°

33

30°

© International Code Council

Map prepared by U.S. Geological Survey in collaboration with the Federal Emergency Management Agency (FEMA)-funded Building Seismic Safety Council’s (BSSC) Code Resource Support Committee (CRSC).

33

REFERENCES Building Seismic Safety Council, 2015, NEHRP Recommended Seismic Provisions for New Buildings and Other Structures: FEMA P-1050, Federal Emergency Management Agency, Washington, DC. Petersen, M.D., Moschetti, M.P., Powers, P.M., Mueller, C.S., Haller, K.M., Frankel, A.D., Zeng, Y., Rezaeian, S., Harmsen, S.C., Boyd, O.L., Field, E.H., Chen, R., Rukstales, K.S., Luco, N., Wheeler, R.L., Williams, R.A., and Olsen, A.H., 2014, Documentation for the 2014 Update of the United States National Seismic Hazard Maps: U.S. Geological Survey Open-File Report 2014-1091, 243 p. Seyhan, E. and Stewart, J.P., 2014, Semi-Empirical Nonlinear Site Amplification from NGA-West2 Data and Simulations. Earthquake Spectra, Vol. 30, No. 3, pp. 1241–1256.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

25

26  Part 2  ■  Building Planning R301.2.2.1 continued 90°

80°

70°

50°

45°

33

33 17 17

40°

17

17

33

17

35° 17

50 33

33

Explanation

17

%g 125

17

100

0 100

100 0

200

300

400

Seismic design category E

83

D2

67

D1

50

D0

33

C

17 0

B

30°

A

500 Miles

25°

100 200 300 400 500 Kilometers

© International Code Council

50

50

5 12 7 6

Alternate Seismic Design Categories

be determined in accordance with Figure R301.2(3) or Section 1613.2 of the International Building Code. The value of SDS determined in accordance with Section 1613.2 of the International Building Code is permitted to be used to set the seismic design category in accordance with Table R301.2.2.1.1, and to interpolate between values in Tables R602.10.3(3), R603.9.2(1) and other seismic design requirements of this code. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R301.2.2.1  ■  Seismic Design Category  

R301.2.2.1.2 Alternative Determination of Seismic Design Category E.  Buildings located in Seismic Design Category E in accordance with Figure R301.2(2), or Figure R301.2(3) where applicable, are permitted to be reclassified as being in Seismic Design Category D2 provided that one of the following is done:

1. A more detailed evaluation of the seismic design category is made in accordance with the provisions and maps of the International Building Code. Buildings located in Seismic Design Category E in accordance with Table R301.2.2.1.1, but located in Seismic Design Category D in accordance with the International Building Code, shall be permitted to be designed using the Seismic Design Category D2 requirements of this code.



2. Buildings located in Seismic Design Category E that conform to the ­following additional restrictions are permitted to be constructed in ­accordance with the provisions for Seismic Design Category D2 of this code: 2.1. All exterior shear wall lines or braced wall panels are in one plane vertically from the foundation to the ­uppermost story. 2.2. Floors shall not cantilever past the exterior walls. 2.3. The building is within the requirements of Section R301.2.2.2.5 R301.2.2.6 for being considered as regular.

Change Significance:  In the 2015 International Residential Code (IRC) and earlier versions, the seismic design maps indicated a value of SDS for a given location. The label SDS stands for the short period design spectral response acceleration (SDS) of a site. The spectral acceleration is an estimate of how much force an earthquake may impart to the soils below a foundation. The estimate is based on a percentage of gravity; if the map contains a value of 0.21, the estimated maximum movement due to an earthquake at that location is 21 percent of the force of gravity. From this estimate, a seismic design category is assigned. Development of the maps incorporate a default assumption of Site (soil) Class. Site soil classes take the range of conditions below a foundation and place them into six categories. Two categories cover different types of solid rock which might be below a foundation. Two categories cover hard-packed soils and two categories cover loose, problematic soils. The IRC always assumes that a structure is built on a hard-packed soil or better. The site soil class that is assumed is Site Class D—the softer of the two hard-packed soil categories. New seismic design category (SDC) maps are included in the 2018 IRC. One map contains the most conservative ‘good quality’ soil type, assuming Site Class C or D, and may increase the local SDC. The second map is allowed if the site is identified as being Site Class A, B or D by geotechnical report or known local soil conditions; this map may lower the design spectral response acceleration, SDS, potentially lowering the seismic design category in locations where soil quality has been determined. Updated seismic design maps prepared by the U.S. Geological Survey (USGS) in collaboration with the Federal Emergency Management Agency (FEMA) and the Building Seismic Safety Council (BSSC) have changed the Seismic Design Category in some areas of the country in the 2018 IRC. The maps reflect updated information on identified faults and potential ground motion attenuation—how the motion of the earth is likely to “die off” over distance. R301.2.2.1 continues Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

27

28  Part 2  ■  Building Planning R301.2.2.1 continued

The USGS also revised the site coefficient Fa, which is a part of the calculations which create the IRC’s seismic maps. This revision occurred in large part due to increased knowledge about how particular types of soils react to earthquake ground motions and to substantial knowledge gains about site response over the past two decades due to an enormous increase in available seismic data. With this update, changes made resulted in Site Class D no longer being the most conservative site soil class for all values of SDS, in some cases soil Site Class C results in a higher SDC. This is not intuitive! To see the change in SDS and Fa values, look at Section 1613 in the 2018 IBC. In high seismic regions, Site Class C with its change in Fa value combined with the SS value—short period maximum considered spectral response acceleration (SS)—can give a higher potential  ground motion value than Site Class D. Therefore, design spectral response accelerations, which determine the Seismic Design Category, increased at a number of locations when the Fa values for Site Class C soil are larger than Fa values for Site Class D. To see the new Fa values, look at the Table 1613.2.3(1) in the 2018 IBC. For a discussion of the changes, read the 2018 IBC Commentary or the 2018 IBC Significant Changes for Section 1613. Because of these changes, two sets of maps are adopted in the 2018 IRC. The updated R301.2(2) Seismic Design Category maps will provide the most conservative assignment of Seismic Design Category and can be used with any site soil type within the limits of current IRC provisions— in other words, for Site Classes A through D. The new R301.2(3) Alternate Seismic Design Category maps will provide less conservative assignment of Seismic Design Category and are permitted to be used when Site Class A, B or D is identified based on geotechnical report or known local soil conditions. The building official may make a determination that use of the alternate maps is permitted, provided adequate information is available to determine site class, either on a community-wide basis or on a site-by-site basis. This may be a geotechnical report for the site or previous geotechnical reports for the region when soils are consistent across the region. As an additional option, alternate determination of Seismic Design Category in accordance with the IBC is still permitted. The technical reasons behind the revisions in IRC Section 301.2.2 and IBC Section 1613 are documented in FEMA P-1050-1, 2015 Edition, Sections C11.4.2 (site classes), C11.4.3 (site coefficients), and C22 (seismic maps). P-1050-1 is available for free download at fema. gov/building-code-resources. Click on the earthquake tab. Maps have been developed by USGS to illustrate locations where Seismic Design Categories increase and decrease when comparing the  2015 IRC seismic maps to the 2018 IRC Figure R301.2(2) maps. These comparison maps are available in the Complete Revision History to the 2018 I-Codes in code change R17-16 or from the USGS in the open file report 2014-1091, Documentation for the 2014 update of the U.S. national seismic hazard maps at pubs.usgs.gov/of/2014/1091. A mapping tool is available through the USGS for determining Seismic Design Category at earthquake.usgs. gov/hazards/designmaps.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R301.2.2.6  ■  Irregular Buildings  

R301.2.2.6

Change Type: Modification Change Summary:  The irregular building section of the seismic provisions of the IRC has been rearranged for greater ease of use.

Irregular Buildings

2018 Code:  R301.2.2.2.5 R301.2.2.6 Irregular buildings.  The seismic provisions of this code shall not be used for irregular structures, or portions thereof, located in Seismic Design Categories C, D0, D1 and D2 and considered to be irregular in accordance with this section. A building or portion of a building shall be considered to be irregular where one or more of the conditions defined in Items 1 through 7 occur. Irregular structures, or irregular portions of structures, shall be designed in accordance with accepted engineering practice to the extent the irregular features affect the performance of the remaining structural system. Where the forces associated with the irregularity are resisted by a structural system designed in accordance with accepted engineering practice, design of the remainder of the building shall be permitted to be designed using the provisions of this code. A building or portion of a building shall be considered to be irregular where one or more of the following conditions occur:

Exception:  For wood light-frame construction, floors with cantilevers or setbacks not exceeding four times the nominal depth of the wood floor joists are permitted to support braced wall panels that are out of plane with braced wall panels below provided that all of the ­following are considered:





1.  Floor joists are nominal 2 inches by 10 inches (51 mm by 254 mm) or larger and spaced not more than 16 inches (406 mm) on center.



2.  The ratio of the back span to the cantilever is not less than 2 to 1.



3.  Floor joists at ends of braced wall panels are doubled.



4.  For wood-frame construction, a continuous rim joist is connected to ends of cantilever joists. When spliced, the rim joists shall be spliced using a galvanized metal tie not less than 0.058 inch (1.5 mm) (16 gage) and 1½ inches (38 mm) wide fastened with six 16d nails on each side of the splice; or a block of the same size as the rim joist and of sufficient length to fit securely between the joist space at which the splice occurs fastened with eight 16d nails on each side of the splice.



5.  Gravity loads carried at the end of cantilevered joists are limited to uniform wall and roof loads and the reactions from headers having a span of 8 feet (2438 mm) or less.

© International Code Council

1. Shear wall or braced wall offsets out of plane. Conditions where exterior shear wall lines or braced wall panels are not in one plane vertically from the foundation to the uppermost story in which they are required.



Irregular-shaped building

2. Lateral support of roofs and floors. Conditions where a section of floor or roof is not laterally supported by shear walls or braced wall lines on all edges. R301.2.2.6 continues

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

29

30  Part 2  ■  Building Planning Exception:  Portions of floors that do not support shear walls or braced wall panels above, or roofs, shall be permitted to extend not more than 6 feet (1829 mm) beyond a shear wall or braced wall line.

R301.2.2.6 continued

3. Shear wall or braced wall offsets in plane. Conditions where the end of a braced wall panel occurs over an opening in the wall below and ends at a horizontal distance greater extends more than 1 foot (305 mm) horizontally past from the edge of the opening. This provision is applicable to shear walls and braced wall panels offset in plane and to braced wall panels offset out of plane as permitted by the exception to Item 1.



Exception:  For wood light-frame wall construction, one end of a braced wall panel shall be permitted to extend more than 1 foot (305 mm) over an opening not more than 8 feet (2438 mm) in width in the wall below provided that the opening includes a header in accordance with the following:

1.  The building width, loading condition and framing member species limitations of Table R602.7(1) shall apply.



2.  The header is composed of: 2.1 Not less than one 2 3 12 or two 2 3 10 for an opening not more than 4 feet (1219 mm) wide. 2.2 Not less than two 2 3 12 or three 2 3 10 for an opening not more than 6 feet (1829 mm) in width. 2.3 Not less than three 2 3 12 or four 2 3 10 for an opening not more than 8 feet (2438 mm) in width.



3.  The entire length of the braced wall panel does not occur over an opening in the wall below.



4. Floor and roof opening. Conditions where an opening in a floor or roof exceeds the lesser of 12 feet (3658 mm) or 50 percent of the least floor or roof dimension.



5. Floor level offsets. Conditions where portions of a floor level are vertically offset. Exceptions:

1.  Framing supported directly by continuous foundations at the perimeter of the building.



2.  For wood light-frame construction, floors shall be permitted to be vertically offset when the floor framing is lapped or tied together as required by Section R502.6.1.



6. Perpendicular shear walls and wall bracing. Conditions where shear walls and braced wall lines do not occur in two perpendicular directions.



7. Wall bracing in stories containing masonry or concrete construction. Conditions where stories above grade plane partially or completely braced by wood wall framing in accordance with Section R602 or cold-formed steel wall framing in accordance with Section R603 include masonry or concrete construction. Where this irregularity applies; the entire story shall be designed in accordance with accepted engineering practice. Exception:  Fireplaces, chimneys and masonry veneer in accordance with this code.

Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R301.2.2.6  ■  Irregular Buildings  

31

Change Significance:  The 2015 IRC Section R301.2.2, Seismic Provisions, was a frequent source of confusion for builders, designers and plans examiners. The irregular building provisions in particular were muddled with a list of conditions that require engineered design followed by multiple exceptions to avoid engineering that often require three or more additional steps to bypass the engineered design. By the time a builder, designer or plans examiner had read through the requirements for a particular irregularity, he or she was often uncertain whether (1) an irregularity existed and (2) whether engineered design was required. The seismic provisions, including provisions for irregular buildings, do not apply to single- or two-family dwellings in Seismic Design Category (SDC) A, B or C regions. Townhouses in SDC A and B regions also do not need to meet the irregular building and seismic requirements. To simplify design and review in SDC D0, D1 and D2 regions and townhouses in SDC C regions, the seismic provisions of Chapter 3 have been reformatted in Section R301.2.2 in the 2018 IRC. A building or portion of the building is considered irregular if it exceeds the limits of one of the items in Section R301.2.2.6 Items 1–7. The exceptions to engineering design continue to follow the description of each irregularity. This revision to Section R301.2.2 intends to clarify the requirements; no technical changes were intended by the reformat.

L W/2 12' max. Floor or roof opening

W/2 12' max.

1

4 W

Setbacks and cantilevers Least dimension Floor or roof opening

5

2

BWP

Vertical floor offset

6 3

Braced wall panel above opening

Nonperpendicular walls

Seven irregularities requiring engineering in high seismic regions Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

© International Code Council

Unsupported floor or roof

32  Part 2  ■  Building Planning

R302.1

Change Type: Modification

Exterior Walls

Change Summary:  References to the International Building Code (IBC) offer additional options and provide flexibility in determining the fire-resistance rating of exterior wall assemblies. Table footnotes have been revised to clarify the correlation between gable end vents and the fire-resistance requirements for projections. 2018 Code:  R302.1 Exterior Walls.  Construction, projections, openings and penetrations of exterior walls of dwellings and accessory buildings shall comply with Table R302.1(1); or dwellings equipped throughout with an automatic sprinkler system installed in accordance with Section P2904 shall comply with Table R302.1(2). Exceptions:

1. Walls, projections, openings or penetrations in walls perpendicular to the line used to determine the fire separation distance.



2. Walls of dwellings individual dwelling units and their accessory structures located on the same lot.



3. Detached tool sheds and storage sheds, playhouses and similar structures exempted from permits are not required to provide wall protection based on location on the lot. Projections beyond the exterior wall shall not extend over the lot line.

Table R302.1(1)   Exterior Walls Minimum Fire Separation Distance

Exterior Wall Element

Minimum Fire-Resistance Rating

Walls

Fire-resistance rated

1 hour—tested in accordance with ASTM E 119, or UL 263 or Section 703.3 of the International Building Code with exposure from both sides

, 5 0 feet

Not fire-resistance rated

0 hours

$ 5 feet

Projections

Openings in walls

Penetrations

Not allowed

N/A

, 2 feet

Fire-resistance rated

1 hour on the underside, or heavy timber or fire-retardant-treated wooda, b

$ 2 feet to < 5 feet

Not fire-resistance rated

0 hours

$ 5 feet

Not allowed

N/A

, 3 feet

25% maximum of wall area

0 hours

Unlimited

0 hours

All

Comply with Section R302.4 None required

3 feet 5 feet , 3 feet 3 feet

For SI: 1 foot 5 304.8 mm. N/A 5 Not Applicable a. Roof eave The fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave overhang if fire blocking is provided from the wall top plate to the underside of the roof sheathing. b. Roof eave The fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave rake overhang where provided that gable vent openings are not installed. Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

Significant Changes to the IRC 2018 Edition

R302.1  ■  Exterior Walls  

33

Table R302.1(2)  Exterior Walls—Dwellings with Fire Sprinklers Minimum Fire Separation Distance

Exterior Wall Element

Minimum Fire-Resistance Rating

Walls

Fire-resistance rated

1 hour—tested in accordance with ASTM E 119, or UL 263 or Section 703.3 of the International Building Code with exposure from the outside

0 feet

Not fire-resistance rated

0 hours

3 feeta

Not allowed

N/A

Fire-resistance rated

1 hour on the underside, or heavy timber or fireretardant-treated woodb, c

2 feeta

Not fire-resistance rated

0 hours

3 feet

Projections

, 2 feet

Openings in walls

Not allowed

N/A

Unlimited

0 hours

Penetrations

All

Comply with Section R302.4

, 3 feet 3 feeta , 3feet 3 feeta

None required

For SI: 1 foot 5 304.8 mm. N/A 5 Not Applicable a. For residential subdivisions where all dwellings are equipped throughout with an automatic sprinkler system installed in accordance with Section P2904, the fire separation distance for nonrated exterior walls not fire resistance rated and for fire resistance rated projections shall be permitted to be reduced to 0 feet, and unlimited unprotected openings and penetrations shall be permitted, where the adjoining lot provides an open setback yard that is 6 feet or more in width on the opposite side of the property line. b. The roof eave fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave overhang if fire blocking is provided from the wall top plate to the underside of the roof sheathing. c. The roof eave fire-resistance rating shall be permitted to be reduced to 0 hours on the underside of the eave rake overhang where provided that gable vent openings are not installed.

4. Detached garages accessory to a dwelling located within 2 feet (610 mm) of a lot line are permitted to have roof eave projections not exceeding 4 inches (102 mm).



5. Foundation vents installed in compliance with this code are permitted.

Germain McDaniel/Shutterstock.com



Gable vent below rake overhang with soffit

R302.1 continues Copyright 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. WCN 02-200-203 Copyright 2019 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s). Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.

34  Part 2  ■  Building Planning R302.1 continued

Change Significance:  The code has long recognized the effectiveness of providing open space between the exterior wall and the lot line in preventing the spread of fire from a building on one property to a building on the adjoining property. Unless the exterior wall is constructed to provide a 1-hour fire-resistance rating, a minimum fire separation distance is required from the lot line. The consensus as to the minimum distance necessary to allow heat from a fire to dissipate and provide a sufficient buffer against the spread of fire has changed somewhat over the years, settling on a minimum distance of 5 feet in the 2006 edition of the IRC. Beginning with the 2012 edition, the code reduced the threshold for nonrated walls to 3 feet of separation when the building was protected with an automatic fire sprinkler system. The 5-foot rule still applies to buildings without sprinkler systems. The choice of providing either adequate fire separation distance or fire-resistant-rated construction also extends to openings, penetrations and projections—some fire-resistance measures must be provided when the fire separation distance to the property line falls below the code-prescribed dimension. Where a one-hour fire-resistant wall assembly is required, the measure for compliance has been that the assembly was tested in accordance with either ASTM E-119 or UL 263. In addition to those referenced standards, the IRC now specifically recognizes all of the options in Chapter 7 of the IBC for determining the fire-resistance rating. The referenced Section 703.3 in the IBC states that any of the alternate methods must be PL

≥2'