2015 code conforming wood design complete

AMERICAN WOOD COUNCIL
2015Code
Conforming
Wood
Design

2015 Code Conforming Wood Design 1
American Wood Council International Code Council
About the American Wood Council
The American Wood Council (AWC) is the voice of North American traditional and engineered
wood products. AWC develops state-of-the-art engineering data, technology, and standards on
structural wood products for use by design professionals, building officials, and wood products
manufacturers to assure the safe and efficient design and use of wood structural components.
AWC also provides technical, legal, and economic information on wood design, green building,
and manufacturing environmental regulations advocating for balanced government policies that
sustain the wood products industry.
Headquarters: 222 Catoctin Circle, SE, Suite 201, Leesburg, VA 20175
District Offices: Santa Rosa, CA; Colorado Springs, CO; Dane, WI; Rock Hill, SC; West Grove, PA
202-463-2766
www.awc.org
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 and resilient structures. Most U.S. communities and many global markets
choose the International Codes. ICC Evaluation Service (ICC-ES) is the industry leader in perform-
ing technical evaluations for code compliance fostering safe and sustainable design and con-
struction.
Headquarters: 500 New Jersey Avenue, NW, 6th Floor, Washington, DC 20001
Regional Offices: Birmingham, AL; Chicago, IL; Los Angeles, CA
1-888-422-7233
www.iccsafe.org
Updates and Errata
While every effort has been made to ensure the accuracy of the information presented, and
special effort has been made to align the information presented with the state-of-the-art, nei-
ther the American Wood Council nor its members assume any responsibility for any particular
design prepared from this publication. Those using this document assume all liability from its
use. Updates or errata are posted to the American Wood Council website at www.awc.org. Tech-
nical inquiries may be addressed to info@awc.org.
Copyright © 2015
American Wood Council
info@awc.org
www.awc.org

2 2015 Code Conforming Wood Design
2015 Code Conforming Wood Design
Introduction
Wood construction offers distinct design options typically not found in a single structural
material. It is inexpensive, readily available, easy to work with, strong and adaptable. The eco-
nomic, environmental and energy efficiency advantages account for more buildings being con-
structed of wood than any other structural material.
The intent of this book is to summarize the allowable wood use in buildings in accordance with
the International Code Council (ICC) 2015 International Building Code® (IBC®). Emphasis will be
placed on the design flexibilities permitted for wood in commercial construction. This is not
meant to be a replacement for the IBC and does not encompass all of the design options in the
IBC. The IBC, along with any local amendments, should always be consulted for applicable spe-
cific requirements related to designs and site conditions.
Table of Contents
1. General Information
2. Type of Construction
3. Allowable Heights and Areas for Type V, IV and III Construction
4. Establishing Fire Resistance
5. Wood Use in “Noncombustible” Construction
6. Wood Features
7. Structural Considerations
8. Precautions during Construction
9. Resources
10. Building Area Tables
1. General Information
Use and Occupancy Classification
Building code requirements are dependent on the appropriate classification of the building or
structure for its design purpose or current occupancy. Eight occupancy classifications are dis-
cussed in this book:
• Group A, Assembly
• Group B, Business
• Group E, Educational
• Group F, Factory/Industrial
• Group I, Institutional
• Group M, Mercantile
• Group R, Residential
• Group S, Storage
The occupancies are described below, but when a structure is proposed for a purpose that is
not specifically listed, it should be classified in the group that the occupancy most nearly resem-
bles in accordance with Section 302.1. The authority having jurisdiction, the building official, has
the ultimate responsibility for rendering interpretations of the code, including designation of the
type of occupancy.
Group H (Hazardous) and Group U (Utility and Miscellaneous) occupancies also may be of
wood construction but are beyond the scope of this book.

Assembly Occupancies
The IBC lists Assembly (Group A) occupancies in Section 303.
Group A occupancies are divided into five subcategories.
Group A-1 includes fixed seating occupancies for viewing per-
forming arts, television studios with audience seating, and
motion pictures. Group A-2 includes buildings in which food
and drink consumption occurs (e.g., restaurants, banquet
halls, casinos, bars and nightclubs); Group A-3 includes places
of religious worship, waiting areas in terminals, recreation, amusement and other assembly uses
not included in the other groups; Group A-4 includes indoor arenas, skating rinks, swimming
pools and tennis courts; and Group A-5 includes outdoor grandstands, stadiums and amusement
park structures.
Business Occupancies
Section 304 describes Business (Group B) occupancies.
Group B uses are for office, professional, or service-type trans-
actions, including the storage of records. It is a broad use
group that often is chosen when a use does not fit another use
group description. Group B includes airport traffic control tow-
ers, ambulatory care facilities, animal hospitals, kennels and
pounds, banks, barber and beauty shops, car washes, civic
administration, outpatient clinics, dry cleaning and laundry (pick-up and delivery stations and
self-service), educational occupancies (above the 12th
grade), electronic data processing, testing
and research laboratories, food processing establishments not associated with restaurants and
dining facilities not more than 2,500 square feet in area, motor vehicle showrooms, post offices,
print shops, professional service offices, radio and television stations, telephone exchanges and
training and skill development facilities not located in a school.
Educational Occupancies
The IBC lists Educational (Group E) occupancies in Section
305. Group E includes any buildings or portions of a structure
used to educate six or more people through the 12th
grade.
Buildings or portions of a structure used for supervision, per-
sonal care or education of more than five children at least 2½
years old are also Group E structures.
Factory/Industrial Occupancies
Section 306 defines Factory/Industrial (Group F) occupancies.
Group F is subdivided into two occupancy groups: Group F-1
and Group F-2. Group F-1, moderate hazard industrial, includes
buildings or portions of buildings used for the manufacturing of
materials that cannot be classified as Group F-2, low hazard
industrial. Group F-1 includes the manufacturing of aircraft,
appliances, motor vehicles, boats, recreational vehicles, busi-
ness machines, photo equipment, construction and agricultural
machinery, engines, metals, woodworking and millwork, and food processing establishments
Figure 1: Auditorium
Figure 2: Office Building
Figure 3: Elementary School
Figure 4: Factory

and commercial kitchens not associated with restaurants and dining facilities and more than
2,500 square feet in area. Group F-1 also includes textile production—canvas, clothing, carpet,
hemp, jute and paper—and laundries, printing and publishing, soaps and plastic products, alco-
holic beverages, optical goods and wood distillation.
Group F-2, low hazard industrial occupancies, are buildings and facilities used for beverage
production (up to 16-percent alcohol), brick, ceramics, glass, gypsum, ice, metal fabrication and
assembly and foundries.
Institutional Occupancies
The IBC lists Institutional (Group I) occupancies in Section 308.
Group I includes four subcategories: Group I-1 includes residential
and custodial care for more than 16 people receiving care (24-
hour care); Group I-2 includes hospitals, child care facilities (24-
hour care), nursing homes and detoxification facilities for more
than five people receiving care; Group I-3 includes jails, detention
centers and prisons; and Group I-4 includes day care facilities for
more than five adults or children receiving care (less than 24-hour
care).
Group I-1 through I-3 occupancies are further broken into conditions based upon the occu-
pants’ ability to respond to an emergency.
Mercantile Occupancies
Section 309 describes Mercantile (Group M) occupancies. Group
M includes department stores, drugstores, markets, motor fuel-
dispensing facilities, retail or wholesale stores and salesrooms.
Essentially any place involving display and sale of merchandise is
classified as a Group M occupancy.
Residential Occupancies
The IBC lists Residential (Group R) occupancies in Section 310.
Group R contains four subcategories. Group R-1 includes hotels,
motels and boarding houses; Group R-2 includes apartments, dor-
mitories, live/work units, timeshare properties and nontransient
hotels, motels and boarding houses. Group R-3 includes single-
and two-family dwellings, adult and child day care facilities with
less than six occupants receiving care and congregate living facili-
ties—transient (10 or fewer occupants) and nontransient (16 or
fewer occupants) and lodging houses (five or fewer guest rooms)
are allowed to be constructed in accordance with the IRC. Group
R-4 includes residential care and assisted living facilities for 6 to 16
clients. Group R-4 occupancies are further broken into two condi-
tions: Condition 1 where all occupants are capable of responding
to an emergency without assistance and Condition 2 where limited
assistance may be necessary for any single occupant.
Figure 5: Nursing Home
Figure 6: Retail Store
Figure 7: Apartments

Storage Occupancies
Section 311 covers Storage (Group S) occupancies. Group S
includes subcategories Group S-1, moderate hazard storage, and
Group S-2, low hazard storage. Group S-1 contains buildings occu-
pied for storage uses that are not classified as Group S-2, including
aircraft hangars, storage of clothing, cloth, fiber, books, paper,
wood, fur, furniture, mattresses, tires, tobacco products, sugar,
soap and glue. Group S-1 also includes indoor storage of boats and
motor vehicle repair garages.
Group S-2 includes buildings used for storage of noncombustible materials such as beverages
up to 16-percent alcohol content, cement, chalk, batteries, electric coils and motors, distribution
transformers, glass, some appliances including stoves, washers and dryers, metal furniture, met-
als, food products, fresh fruit and frozen foods. Open and enclosed parking garages are also
Group S-2 occupancies.
Referenced Code and Standards
The IBC is developed by the International Code Council. Industry and profes-
sional standards are referenced in the IBC to clarify specific code requirements.
Chapter 35 of the IBC provides a list of the standards referenced, the agency
that writes the standard, the identification and title of the standard, and its
effective date.
Standards represent consensus on how a material, product or assembly is to
be designed, manufactured, tested or installed so it achieves a specified level of
performance. Several key standards relating to design of wood structures are
utilized by the IBC. Specifically, the 2015 IBC references the American Wood
Council (AWC) 2015 National Design Specification® (NDS-15®) for Wood Con-
struction, the AWC SDPWS-15, 2015 Special Design Provisions for Wind and Seis-
mic, and the 2015 Wood Frame Construction Manual (WFCM) for One- and
Two-Family Dwellings. The NDS details structural and fire design methods for
the use of lumber, timber, prefabricated wood I-joists, structural composite lum-
ber, wood structural panels and cross-laminated timber, using either Allowable
Stress Design (ASD) or Load and Resistance Factor Design (LRFD). The SDPWS
addresses materials, design and construction of wood members, fasteners and
assemblies used to resist wind and seismic forces. The WFCM includes design
and construction provisions for connections, wall systems, floor systems, and
roof systems. A range of structural elements is also covered, including sawn lum-
ber, structural glued laminated timber, wood structural sheathing, I-joists, and
trusses.
Section 9 of this book, Resources, provides information on how to obtain
these standards and other related materials.
Figure 8: Parking Garage
Figure 9: NDS,
SDPWS and
WFCM

2. Type of Construction
Chapter 6 of the IBC defines types of construction, with wood frame construction typically
found in Type V, IV and III. Additionally, the IBC has specific applications that permit the use of
wood in construction in Type I and II. These circumstances will be addressed in Sections 5 and 6
of this book.
Type V Construction
Type V construction permits the use of wood or other
approved materials for structural elements, including structural
frame members, bearing walls, floor and roof construction, as
well as nonbearing elements such as exterior walls and interior
partitions. Type V construction is further defined as Type VA (all
interior and exterior load-bearing walls, floors, roofs and all
structural members are designed or protected to provide a
minimum 1-hour fire-resistance rating) and Type VB (no fire-
resistance rating is required).
Type IV Construction
Type IV construction (Heavy Timber, HT) has exterior walls
made of noncombustible materials, fire-retardant-treated
wood (FRTW), or cross-laminated timber (CLT) protected in
accordance with Section 602.4.2. Interior building elements
must be of solid or laminated wood without concealed spaces
(for partitions, see below). Columns supporting roof and ceiling
loads must be a minimum nominal dimension of 6 inches by 8
inches and 8 inches by 8 inches if supporting floor loads. Floor
beams and girders must be a minimum nominal dimension of 6
inches by 10 inches, and roof beams and girders must be a minimum nominal dimension of 4
inches by 6 inches. Flooring must be a minimum nominal 3-inch thickness covered with 1-inch
nominal dimension tongue-and-groove flooring or 4-inch-thick cross-laminated timber (CLT).
Roof decking must be a minimum nominal 2-inch thickness, 11
/8-inch-thick wood structural pan-
els, or 3-inch-thick CLT. Partitions must be 1-hour fire-resistance-rated construction or a mini-
mum two layers of 1-inch nominal board or laminated construction 4 inches thick.
Type III Construction
Type III construction requires exterior walls to be noncom-
bustible material or FRTW having a minimum 2-hour fire-resis-
tance rating. All of the other building elements are permitted to
be wood or other approved materials. Type IIIA construction
needs to provide a minimum 1-hour fire-resistance rating for all
building elements other than nonbearing walls, and Type IIIB
construction does not require any fire-resistance rating other
than the exterior load-bearing wall.
Figure 10: Type V Construction
Figure 11: Type IV Construction
Figure 12: Type III Construction

Type I and II Construction
Type I and II construction requires build-
ing elements to be of noncombustible
materials. Sections 5 and 6 of this book
outline circumstances where wood is per-
mitted in Type I and II buildings.
3. Allowable Heights and Areas
for Type V, IV and III Construction
When the first edition (2000) of the IBC
was published, wood buildings were
allowed to have areas and heights com-
mensurate with the largest buildings per-
mitted for each construction type under at
least one of the regional legacy codes.
Since then, allowable building sizes have
not changed significantly, although the
number of buildings that qualify for unlim-
ited area under the special provisions of
Section 507 has expanded. In addition, spe-
cial allowances for various building fea-
tures, such as sprinklers or the use of fire-
retardant-treated wood (FRTW), continue
to be added. As a result, size thresholds for
wood structures have more often been
determined by structural considerations
than by code limitations. The 2015 IBC is the first edition to recognize new mass timber products
such as CLT and other advanced engineered wood products. Because of the structural capabili-
ties of mass timber, wood design is better able to take advantage of the generous building sizes
permitted by the IBC. Greater building heights, commercial loads, and long clear spans are now
more feasible, allowing the full environmental, economic, and aesthetic benefits of designing in
wood to be available for more buildings.
General building height and area allowances are given in Chapter 5 of the IBC. Limitations are
shown in IBC Tables 504.3, 504.4 and 506.2 for height, number of stories, and per story area,
respectively. Excerpts of the tables are shown in Figure 14. These values are unmodified by the
frontage increase, as explained in this section.
Figure 13: Type I Construction

NS - nonsprinklered
S - sprinklered (NFPA 13 System)
S13R - sprinklered NFPA 13R requirements (NFPA 13R System)
S1 - single-story sprinklered building (NFPA 13 System)
SM - multistory sprinklered building (NFPA 13 System)
Figure 14: Table 504.3, 504.4 and 506.2 Excerpts
Occupancy Classification
Type of Construction
Type III Type IV Type V
A B HT A B
TABLE504.3:Allowable
BuildingHeight
(FtaboveGrade)
A, B, E, F, M, S, U
NS 65 55 65 50 40
S 85 75 85 70 60
I-1 Condition 1, I-3
NS 65 55 65 50 40
S 85 75 85 70 60
I-1 Condition 2, I-2
NS
65 55 65 50 40
S
I-4
NS 65 55 65 50 40
S 85 75 85 70 60
R
NS 65 55 65 50 40
S13R 60 60 60 60 60
S 85 75 85 70 60
TABLE504.4:AllowableNumber
ofStoriesaboveGrade
A-1, A-2, A-3, A-4
NS 3 2 3 2 1
S 4 3 4 3 2
B
NS 5 3 5 3 2
S 6 4 6 4 3
E
NS 3 2 3 1 1
S 4 3 4 2 2
M
NS 4 2 4 3 1
S 5 3 5 4 2
S-2
NS 4 3 4 4 2
S 5 4 5 5 3
R-1
NS
4 4 4
3 2
S13R 4 3
S 5 5 5 4 3
R-2
NS
4 4 4
3 2
S13R 4 3
S 5 5 5 4 3
TABLE506.2:AllowableAreaFactor
A-2, A-3
NS 14,000 9,500 15,000 11,500 6,000
S1 56,000 38,000 60,000 46,000 24,000
SM 42,000 28,500 45,000 34,500 18,000
B
NS 28,500 19,000 36,000 18,000 9,000
S1 114,000 76,000 144,000 72,000 36,000
SM 85,500 57,000 108,000 54,000 27,000
E
NS 23,500 14,500 25,500 18,500 9,500
S1 94,000 58,000 102,000 74,000 38,000
SM 70,500 43,500 76,500 55,500 28,500
M
NS 18,500 12,500 20,500 14,000 9,000
S1 74,000 50,000 82,000 56,000 36,000
SM 55,500 37,500 61,500 42,000 27,000
S-2
NS 39,000 26,000 38,500 21,000 13,500
S1 156,000 104,000 154,000 84,000 54,000
SM 117,000 78,000 115,500 63,000 40,500
R-1, R-2
NS
24,000 16,000 20,500 12,000 7,000
S13R
S1 96,000 64,000 82,000 48,000 28,000
SM 72,000 48,000 61,500 36,000 21,000

The maximum height and area of a structure is dependent on the occupancy classification and
the presence of an automatic sprinkler system, as tabulated in Tables 504.3, 504.4, and 506.2. Addi-
tionalincreasesmay be granted depending on the building location on the lot or using some of the
design options recognized in Chapter 5. Upper limits for the size of certain occupancies without
sprinklers are located in Chapter 9. These increases and limits are discussed in detail in this sec-
tion.
Allowable Building Area
Equation 5-1 establishes the maximum allowable floor area for a single-occupancy building
with no more than one story above grade plane. Equation 5-2 establishes the maximum allow-
able floor area of a single-occupancy building with more than one story above grade plane, and
simply includes the additional factor, Sa, as defined below.
Aa = At + (NS  If) (Equation 5-1)
Aa = [At + (NS  If)]  Sa (Equation 5-2)
where:
Aa = Allowable building area (square feet).
At = Tabular allowable area factor (NS, S1, S13R or SM value, as applicable) in accordance
with Table 506.2 (square feet).
NS = Tabular allowable area factor in accordance with Table 506.2 for a nonsprinklered
building (regardless of whether the building is sprinklered).
If = Area factor increase due to frontage (percent) as calculated in accordance with Sec-
tion 506.3.
Sa = Actual number of building stories above grade plane, not to exceed three. For build-
ings equipped throughout with an automatic sprinkler system installed in accordance
with Section 903.3.1.2, use the actual number of building stories above grade plane,
not to exceed four.
Allowable Increases for Frontage
Buildings adjacent to open space adjoining a public way with the exterior wall a minimum of
20 feet from the lot line, or the far edge of the public way for more than 25 percent of the
building perimeter, may increase the allowable floor area from Table 506.2 using Equations 5-1
and 5-2. The area factor increase based on frontage is calculated using Equation 5-5.
If = [F / P – 0.25] W / 30 (Equation 5-5)
where:
If = Area factor increase due to frontage.
F = Building perimeter that fronts on a public way or open space having 20 feet open
minimum width (feet).
P = Perimeter of entire building (feet).
W = Width of public way or open space (feet) in accordance with Section 506.3.2.

A weighted average frontage width (W) is used when W varies along the perimeter. W is the
open space width plus the width of the public way, if applicable, and widths greater than 30 feet
will only receive credit for a value of 30 feet in accordance with Section 506.3.2. The maximum
increase that can be obtained for frontage would occur when 100 percent of the perimeter has
frontage of 30 feet or more and would result in a 75-percent floor area increase.
Weighted Average
Section 506.3.2 allows the use of a weighted average to calculate the frontage width around a
building. Figure 15 illustrates the use of the weighted average equation.
Note that this equation is only used for open space widths greater than or equal to 20 feet.
Open space widths greater than 30 feet are reduced to 30 feet before calculating a weighted
average.
Weighted average W = (L1  w1 + L2  w2 + L3  w3...) / F (Equation 5-4)
where:
Ln = Length of a portion of the exterior perimeter wall (feet).
wn = Width of open space associated with that portion of the exterior perimeter wall
(feet).
F = Building perimeter that
fronts on a public way or
open space having a width of
20 feet or more (feet).
Length of Walls:
L1, L2, L3 and L4 = 200 ft
Frontage Width:
w1 = 22 ft w3 = 55 ft
w2 = 45 ft w4 = 50 ft
F = 200 x 4 = 800 ft
For w2, w3, and w4, use the maximum
30-foot width in the weighted average
equation.
(Equation 5-4)
Interior lot lines
Measurement
at 90° from
building face
W2
W1
W3
W4
Wall 1
Wall 3
Wall2
Wall4
CL Public way
CL Public way
Public ways
Lot lines
Lot lines
Figure 15: Open Space Width
W
L1 w1 L2 w2 L3 w3 L4 w4+++ 
F
---------------------------------------------------------------------------------------------------=
W
200 22 200 30 200 30 200 30+++ 
800
-------------------------------------------------------------------------------------------------------------- 28 ft==

Frontage Increase Calculation:
The frontage calculation determines the additional allowable increase in area due to open
space around the building. Figure 16 illustrates the frontage increase concept for a nonsprin-
klered two-story restaurant of Type IIIA construction.
Given:
– Two-story restaurant
– Type IIIA construction
– Street width of 22 feet
Determine:
– Maximum allowable building area
Solution:
Length of Walls:
L1 = 120 ft L3 = 120 ft
L2 = 180 ft L4 = 180 ft
Frontage Width:
(Note: Public way width is 22 ft)
w1 = 15 ft w3 = 10 + 22 = 32 ft
w2 = 25 ft w4 = 30 + 22 = 52 ft
For w1, the open space width is less
than 20 feet; this side of the building
is not included in the frontage calculations. For w3 and w4, use w = 30 feet (maximum) in the
weighted average in accordance with Section 506.3.2.
Frontage Length:
F = L2 + L3 + L4 = 180 + 120 + 180 = 480 ft
(Equation 5-4)
At = NS = 14,000 sq ft
If = (F/P – 0.25)  W/30 (Equation 5-5)
If = [(480 / 600) – 0.25]  28 / 30 = 0.51
Sa = 2 stories
Aa = [At + (NS × If)] × Sa (Equation 5-2)
Aa = [14,000 + (14,000 × 0.51)] × 2 = 42,280 sq ft maximum building area; the maximum allowable
area per floor is 21,140 square feet.
Interior
Lot Lines
C
L
Public Way
Lot Lines
L1 = 120 ft,
W1 = 15 ft
L3 = 120 ft,
W3 = 10 ft + 22 ft = 32 ft
L4 = 180 ft,
W4 = 30 ft + 22 ft = 52 ft
L2 = 180 ft
W2 = 25 ft
22ft
Street Width
Figure 16: Frontage Increase Calculation
W
L1 w1 L2 w2 L3 w3 L4 w4+++ 
F
------------------------------------------------------------------------------------------------=
W
0 180 25 120 30 180 30+++ 
480
------------------------------------------------------------------------------------------- 28 ft==

No individual story is permitted to exceed the allowable area as determined by Equation 5-2
using the value of Sa = 1. Assuming a smooth rectangular building, both individual story areas
(21,600 ft2
) as well as the total building area (43,200 ft2
) exceed those permitted for a sprinklered
building (21,140 ft2
and 42,280 ft2
, respectively). This example assumed a nonsprinklered build-
ing, but it is worth noting that a Group A-2 above the level of exit discharge, or having a fire area
exceeding 5,000 sq. ft., or having an occupant load of 100 or more, requires sprinklers in accor-
dance with Section 903.2.1.2, as explained in the next section.
The actual areas of the first and second story are larger than the allowed maximum area per
story. Possible solutions for this issue include: changing the construction type, subdividing the
area with fire walls, moving the building on the lot, providing a sprinkler system, or reducing the
building area.
For a building otherwise qualifying as an unlimited area building in accordance with Section
507 that does not have the required 60 feet of fire separation at all perimeter locations but has
at least 30 feet of separation all around, the value of W/30 can be taken up to 2, in accordance
with the exception in Section 506.3.2. The result would be nearly a 150-percent floor area
increase. In this case, the value W is not limited to 30 feet, but 60 feet.
Allowable Increases for Automatic Sprinkler Systems
When a building is equipped throughout with an NFPA 13-compliant automatic sprinkler sys-
tem, the allowable floor area per story is permitted to be increased by 300 percent for a one-
story building and 200 percent for a multistory building, as Table 506.2 shows.
In addition to the area increase, Section 504 also permits the building heights to be increased
by 20 feet and the number of stories above grade plane to be increased by one story, as shown in
Tables 504.3 and 504.4, respectively. This applies to all occupancies addressed in this book,
except Group I-2 and Group I-1 Condition 2 occupancies, which are not allowed the increase of a
story when an automatic sprinkler system is installed.
For Group R buildings, a similar height increase (but no area increase) is given for the use of
NFPA 13R-compliant systems: up to 60 feet and four stories in accordance with Section 504.3.
Figure 17 illustrates the combined effect of front-
age and automatic sprinkler systems on the allow-
able area calculation.
Given: Single-story Type VB grade school
Provided with an NFPA 13-compliant
automatic sprinkler system throughout
and located on lot as shown.
Determine: Maximum allowable building area
Solution:
NS = 9,500 (Table 506.2)
Frontage Increase (Section 506.3)
If = (F/P – 0.25)  W/30 (Equation 5-5)
If = [(350 / 700) – 0.25]30 / 30 = 0.25 (where W > 30, use 30)
Note: The weighted average calculation was not needed in this example.
250′
100′
60′
40′
Figure 17: Allowable Building Area Calculation

At = 38,000 (due to the sprinkler increase) (Table 506.2)
Total Allowable area (Section 506.2.1)
Aa = At + (NS If  (Equation 5-1)
Aa = 38,000 + (9,5000.25) = 40,375 square feet maximum allowable building area
Actual area = 250100 = 25,000 sq ft  OK
Area Limits for Nonsprinklered Buildings in Chapter 9
Many occupancies have floor area limits allowed by Chapter 5 that are greater than fire areas
permitted in Chapter 9 for nonsprinklered buildings. The same thresholds apply to all construc-
tion types, not just wood. The allowable area per story can exceed allowable fire areas and a
sprinkler system may be required.
If sprinklers are provided, allowable area increases for both sprinklers and open frontage, if
applicable, may be taken. Alternatively, fire areas may be kept below sprinkler thresholds by
compartmentalizing floor areas with fire-resistance-rated construction in accordance with the
definition of “Fire Area” and the requirements of Chapter 7. For several occupancies covered in
this book, the requirement for sprinklers can also be triggered by specific use, height above
grade or occupant load.
Sprinklers offer a substantial increase to life safety, which is well documented and merits the
consideration of designers for that reason alone. But their advantages can also be economic. The
code offers considerable trade-offs for providing sprinklers, including:
• Reductions in corridor ratings and corridor opening protection,
• Flexibility in means of egress (travel distance to exits, number and separation of exits,
common path of travel),
• Reductions in dwelling unit separations,
• Alternative to emergency escape openings,
• Alternative to certain fire and smoke damper requirements, and
• Interior finish flexibility.
For these reasons, the addition of sprinklers should always be considered in the overall cost
analysis for any project.
Maximum Building Area Tables
The tables at the end of this book illustrate the allowable area and height increases permitted
for individual occupancies.
• Tables 1, 3, 5, 7, 9, 12 and 17 list nonsprinklered maximum building area per story for each
occupancy.
• Tables 2, 4, 6, 8, 11, 13, 16 and 18 list NFPA 13-compliant sprinklered maximum building area
per story for each occupancy.
• Tables 10 and 15 list NFPA 13R-compliant sprinklered maximum building area per story for
Group I and R occupancies.
• Table 14 lists NFPA 13D-compliant sprinklered maximum building area per story for Group R
occupancies.

Total Building Area Limit
Single Occupancy
Ignoring any frontage increases, a single occupancy building with three or more stories above
grade has a total building area of the allowable building area per story found in Table 506.2 mul-
tiplied by three in accordance with Section 506.2.3. Therefore, buildings with four or more sto-
ries of the same floor area will have smaller maximum areas per floor than a three-story building
of the same type of construction and occupancy. For two-story buildings, the total building area
is the maximum allowable building area per story found in Table 506.2 multiplied by two. The
maximum area of any story above grade cannot exceed the allowable area (Aa) as determined by
Equation 5-2 using the value of Sa = 1. A single basement is not included in the total allowable
building area in accordance with Section 506.1.3.
The actual building area for all stories added
together must not exceed the total allowable
building area.
1-Story Building
Total Allowable Building Area
Aa = At + (NS × If)
2-Story Building
Aa = [At + (NS × If)] × Sa
where Sa = 2
3 and 3+ Story Building
Aa = [At + (NS × If)] × Sa
where Sa = 3
where:
Aa = allowable building area
At = tabular allowable area
Sa = Actual number of building stories above
grade plane, not to exceed three
The maximum allowable building area for resi-
dential buildings provided throughout with an
NFPA 13R-compliant automatic sprinkler sys-
tem is determined by multiplying the allowable
building area per story (At), as determined in
Table 506.2, by the number of stories above
grade plane in accordance with Section 506.2.3
up to four stories in accordance with the scope
of the NFPA 13R standard.
Note that use of NFPA 13R means there is no
automatic sprinkler area increase as shown in
Max. 37,500 sq. ft.
Max. 37,500 sq. ft.
Max. 37,500 sq. ft.
Max. 37,500 sq. ft.
Max. 37,500 sq. ft.
Max. 37,500 sq. ft.
2-story building
1-story building
3-story building
4-story building
Stories of equal area:
- Each story may not exceed 112,500/4 = 28,125 sq. ft.
Stories of unequal area:
- No single story can exceed 37,500 sq. ft.
Max. 37,500 X 2 =
75,000 sq. ft.
Max. 37,500 X 3
= 112,500 sq. ft.
Max. 37,500 X 3
= 112,500 sq. ft.
Figure 18: Maximum Building Area

Table 506.2. A building area increase can only be applied due to the frontage calculations. The
building height increase for Group R structures still applies in accordance with Table 504.3.
Mixed Occupancy
Mixed occupancy buildings are permitted a total allowable building area calculated in accor-
dance with Section 508. But a single-story basement does not need to be included in the total
allowable building area when the basement does not exceed the area permitted for a single story
(see Section 506.1.3).
More than one occupancy in a single building can be accommodated by using the allowable
area of the most restrictive occupancy (referred to as "nonseparated occupancies" in accordance
with Section 508.3). Alternatively, the occupancies can be regulated as a "separated occupan-
cies" (Section 508.4) to allow somewhat larger floor areas. This methodology will often mandate
separation of the occupancies by fire barriers or horizontal assemblies, or both, in accordance
with Table 508.4. The code also accommodates limited area spaces that are accessory to the
function of the main occupancy if the restrictions of Section 508.2 are followed. See Sections
506.2.2 and 506.2.4 for additional limits for single- and multistory mixed occupancy buildings.
Note that "incidental uses" (as opposed to accessory uses) are covered in Section 509 of the code
and always require separation in accordance with Table 509.
Unlimited Area Buildings
Buildings of certain uses that meet frontage requirements are permitted to be unlimited in
area, as explained in the following sections.
One-Story Buildings—Sprinklered
The following unlimited area buildings with a single story above grade plane are permitted if
the building is equipped throughout with an NFPA 13-compliant automatic sprinkler system and
surrounded on all sides by public ways or yards not less than 60 feet wide. The open frontage can
be reduced in some circumstances (Section 507.2.1).
Unlimited area Group B, F, M and S buildings of any construction type are permitted with no
special restrictions in Section 507.4, as long as sprinklers and 60 feet of open frontage are pro-
vided.
Unlimited area Group A-4 buildings of Type IIIA, IIIB and IV construction are permitted by Sec-
tion 507.4. For indoor activities such as tennis, swimming, skating and equestrian venues, the
sprinkler system is not required if exit doors lead directly outside from participant areas and a
fire alarm system with manual fire alarm boxes is installed as required by Section 907.
Unlimited area Group E buildings are permitted by Section 507.11 when of Type IIIA or IV con-
struction and each classroom has two means of egress, with one means of egress a direct exit to
the outside of the building complying with Section 1022.
Unlimited area Group A-3 buildings of Type III or IV construction, used as a place of religious
worship, community hall, dance hall, exhibition hall, gymnasium, lecture hall, indoor swimming
pool or tennis court, are permitted by Section 507.7 provided that the building does not have a
stage other than a platform, the assembly floor is located within 21 inches of street or grade level
and all exits are provided with ramps to the street or grade level.
Group A-1 and A-2 occupancies of Type III or IV construction are permitted by Section 507.4.1
in mixed occupancy buildings containing Group B, F, M or S occupancies of unlimited area pro-
vided that the occupancies are separated as required in Section 508.4.4 with no reduction

allowed in the fire-resistance rating of the separation based on the installation of an automatic
sprinkler system and all exit doors from Group A-1 and A-2 occupancies must discharge directly
to the exterior of the building.
One-Story Buildings—Nonsprinklered
Nonsprinklered unlimited area Group F-2 or S-2 buildings, of any construction type, with a sin-
gle story are permitted by Section 507.3 provided they are surrounded on all sides by public ways
or yards not less than 60 feet wide.
Two-Story Buildings—Sprinklered
Unlimited area Group B, F, M or S buildings up to two stories above grade plane of any con-
struction type are permitted by Section 507.5 provided they are equipped throughout with an
NFPA 13-compliant automatic sprinkler system and are surrounded on all sides by public ways or
yards not less than 60 feet wide.
Section 507.2.1 allows up to 75 percent of the perimeter open space to be less than 60 feet in
width for unlimited area one- and two-story Group B, F, M and S buildings. There must be at least
40 feet provided and the exterior wall and all openings on those portions require 3-hour mini-
mum fire-resistance and fire protection ratings.
Allowable Increases with Fire Walls
A fire wall is a fire-resistance-rated wall with protected openings that restricts the spread of
fire and extends continuously from the foundation to or through the roof. Fire walls built in com-
pliance with Section 706 create separate buildings for the purpose of area limitations and other
code-required features. Fire walls separating Group A, B, E, I, R-1 and R-2 occupancies require a
3-hour minimum fire-resistance rating that can be reduced to a 2-hour minimum for Type V con-
struction. Fire walls separating Group F-1, S-1 and M occupancies require a 3-hour minimum fire-
resistance rating with no reduction allowance while Group F-2, S-2, R-3 and R-4 occupancies
require only a 2-hour minimum fire-resistance rating. Each portion of a building separated by a
fire wall is evaluated individually for allowable heights and areas based on the type of construc-
tion.
Fire walls in Type V construction may be wood frame; in other construction types they must be
of noncombustible materials in accordance with Section 706.3.
Special Provisions for Stacked Buildings
Under specific circumstances, buildings of different types of construction are allowed to be
built on top of each other and are commonly referred to as stacked or pedestal buildings. They
are only permitted when following the provisions of Section 510. Section 510.2 requires a 3-hour
minimum fire-resistance-rated horizontal assembly between the lower and upper buildings. The
lower building must be Type IA construction. The upper building’s type of construction and
building height in stories are determined as if it did not have a building below thus permitting all
types of construction above the Type IA pedestal. The total height in feet, however, is still limited
and measured from grade plane in accordance with Section 510.2, Item 6. Group B, M, R and S
occupancies (including Group S-2 open and enclosed parking garages) are permitted in the upper
building, subject to the building height and area limitations discussed previously. Multiple Group

A occupancies, each with an occupant load of less than 300, are also permitted. The lower build-
ing is permitted to be any occupancy except Group H.
Type IIIA construction in Groups R-1 and R-2
may be increased above the general limitations of
Sections 503 and 504 to six stories and 75 feet
where the first floor assembly has a fire-resistance
rating of not less than 3 hours and the floor area is
subdivided by 2-hour fire-resistance-rated fire
walls into areas of not more than 3,000 square feet
as provided by Section 510.5.
For Group R occupancies, the number of stories
of a building with a single-story Group S-2 parking
garage of Type I construction or open parking
garage of Type IV construction, with grade
entrance, are permitted by Section 510.4 to be
measured from the floor above such a parking
area. The floor assembly between the parking
garage and the Group R above must be the type of construction required for the parking garage,
must provide a fire-resistance rating in accordance with Table 508.4 and must comply with the
requirements for horizontal assemblies in accordance with Section 711.
Section 510.7 contains another alternative with conditions independent of Section 510.2. The
upper building height and area are limited as previously discussed and the open parking garage is
regulated in Section 406.5 and is permitted to be Type IV construction. The height of the upper
building is measured from the grade plane and includes the open parking garage level. See the
other conditions listed in Section 510.7 regarding separate means of egress and other protected
features if this alternative is used.
Lastly, Group S-2 open parking garages above a Group B or M occupancy are allowed in accor-
dance with Section 510.8.
Multiple upper buildings may be positioned on a single parking structure complying with Sec-
tions 510.2, 510.3 or 510.8 and be treated as separate buildings in accordance with Section
510.9.
4. Establishing Fire Resistance
Table 601 establishes the required fire resistance of building elements (primarily the structural
frame, walls, floors and roofs) due to the construction type of the building (e.g., Type IIIA, Type
IIIB, Type IV, etc.). Required ratings are given in hours. The exception is Type IV, where the wood
structural elements are assumed to have inherent fire resistance due to their required minimum
dimensions (no fire-resistance rating is required except for exterior walls).
Fire resistance describes the rate at which a building material degrades due to a fire. Resis-
tance is based on how fast a material will burn, how rapidly the strength of the member or
assembly is affected by the fire and whether the member or assembly can maintain its design
strength. Fire resistance of wood members and assemblies may be established by testing in
accordance with Section 703.2 or by any one of six means listed in Section 703.3. The most com-
mon methods are indicated below.
Figure 19: Pedestal Building

Tested Assemblies
Tested assemblies include wood assemblies that have been tested to the ASTM E119 or UL 263
standard. Using one of these standards, an assembly is typically assigned a 1- or 2-hour fire rating
depending on its performance in the fire test(s). Designers choose listed assemblies from various
fire-resistance publications or directories, such as the UL Fire Resistance Directory or the Gypsum
Association Fire Resistance Design Manual
Prescriptive Assemblies
The fire resistance of certain wood assemblies is
prescribed in Section 721 based on testing using
ASTM E119 or UL 263. Section 703.3 permits the use
of other sources, as well. Often used is the AWC
publication AWC DCA 3, Fire-Rated Wood Floor and
Wall Assemblies, which is available for free to down-
load at
www.awc.org/codes-standards/publications/dca3.
Calculated Fire Resistance
The fire resistance of exposed wood members
may be calculated using the provisions of Chapter 16
of the National Design Specification® (NDS®) (see
Section 722.1). AWC’s Technical Report No. 10
(TR10), Calculating the Fire Resistance of Exposed
Wood Members, contains full details of the NDS
method as well as design examples, and it is available for free to download at
www.awc.org/codes-standards/publications/tr10.
The fire resistance of wood frame assemblies also may be calculated
using the provisions of Section 722.6, which is based on the known fire
resistance of many tested assemblies. This method is limited to fire-resis-
tance ratings of no more than 1-hour. The information in AWC DCA 4, Com-
ponent Additive Method (CAM) for Calculating and Demonstrating
Assembly Fire Endurance, was the basis for these code provisions. It is avail-
able for free to download at
5. Wood Use in “Noncombustible” Construction
Type I and II construction typically require the use of noncombustible materials. Section 603
specifies 26 applications where combustible materials are permitted without reclassifying the
building to a different type of construction. For example, fire-retardant-treated wood walls and
roof construction are permitted under certain conditions. Wood blocking is permitted for hand-
rails, millwork, cabinets and window and door frames. Furring or nailing strips used in connec-
tion with “set-out” construction are also permitted. Show windows, wooden bulkheads below
the window and nailing and furring strips are also permitted to be wood if the window is not
more than 15 feet above grade.
Figure 20: Heavy Timber Member
Exposed to Fire
Figure 21: NDS

Fire-Retardant-Treated Wood
There are many applications for fire-retardant-treated wood (FRTW) in Type I and II construc-
tion. FRTW is permitted in nonbearing partitions where the fire-resistance rating does not
exceed 2 hours, and it may be used in nonbearing exterior walls that do not require a fire-resis-
tance rating. Roof construction, including structural framework, permits FRTW, except for Type
IA construction of three stories or more where the lowest roof member is less than 20 feet mea-
sured vertically from the upper floor.
As mentioned above, FRTW may also be used in exterior walls of Type III and IV construction,
which are required to be noncombustible by definition. Because of this, certain code provisions
that assume noncombustible exterior walls have become difficult to interpret. But usually a prac-
tical solution to these code questions can be achieved by working closely with the code official.
For instance, the addition of solid FRTW wood blocking of a certain thickness in floor cavities that
intersect with the exterior wall in Type III construction is an appropriate precaution to maintain
the fire resistance and material integrity of the exterior wall.
Heavy Timber Members
Heavy timber (HT) construction is permitted in roof con-
struction as an alternative to 1-hour or less fire-resistance-
rated noncombustible construction. This would allow HT use
in all roof construction except Type IA. HT columns and
arches are permitted on the exterior of walls if the fire sepa-
ration distance is 20 feet or more.
6. Wood Features
Wood may be used as an architectural or structural com-
ponent of a building. It is renewable and biodegradable, using less energy to manufacture than
steel, concrete, aluminum or plastic. Wood use in foundations, doors, windows, exterior and
interior finishes, trim and roofing contributes to the aesthetics of the building in an economical
and efficient manner.
Wood Foundations
Wood foundations for buildings are permitted when designed and
installed in accordance with the AF&PA/AWC Permanent Wood Foundation
Design Specification (PWF). Insulated wood foundation systems conserve
energy and easily accommodate installation of wiring, plumbing, ductwork
and interior finishes. Savings in labor, time and material costs may be
achieved when such systems are used.
Wood Walls and Partitions
Wood stud framing is permitted for all load-bearing and nonload-bearing interior walls and
partitions in Type III and V construction. Type IV construction permits wood stud-framed parti-
tions of 1-hour fire-resistance-rated construction (Section 602.4.8.1) or solid wood formed by at
least two layers of 1-inch matched boards or 4-inch-thick laminated construction. In Type I and II
construction, partitions dividing single tenant offices or retail and not creating corridors serving
30 or more occupants are permitted to be FRTW, 1-hour fire-resistance-rated construction or of
wood panels or similar light construction up to 6 feet in height (Section 603.1, Item 11).
Figure 22: Heavy Timber Construction
Figure 23: PWF

Wood Interior Finish
In general, wood materials may be used as interior
finish in almost all occupancies. Table 803.11 places
minimum performance classifications on finish mate-
rials based on their location in the building. The mate-
rial performance classification is determined by
testing in accordance with the ASTM E84 or UL 723
standard and results in a classification as Class A
(flame spread index 0–25); Class B (26–75) or Class C
(76–200). All classifications must have a smoke-devel-
oped index between 0–450 (Section 803.1.1).
Nonsprinklered buildings typically require more
restricted flame spread materials than sprinklered buildings. Figure 25 contains two tables out-
lining the required interior finish minimum classification for exit enclosures and passageways,
corridors and enclosed spaces and rooms.
a. This simplified table is not comprehensive; more exceptions can be found in Table 803.11 footnotes.
b. Except in Group I-3, buildings less than three stories above grade plane permit the reduction of the exit enclo-
sure and exit passageway classifications to Class B.
c. Exit enclosures and exit passageways are permitted to use Class C wainscotting or paneling in the grade
lobby for not more than 1,000 square feet of applied surface when applied to a noncombustible base.
d. Lobby areas in corridors may use Class B interior finishes for Group A occupancies.
e. Places of assembly with an occupant load of 300 persons or less may use Class C interior finishes
a. This simplified table is not comprehensive; more exceptions can be found in Table 803.11 footnotes.
b. Automatic sprinkler system meeting the requirements of NFPA 13 or NFPA 13R as appropriate.
c. Except in Group I-3, buildings less than three stories above grade plane permit the reduction of the exit enclo-
sure and exit passageway classifications to Class C.
d. Exit enclosures and exit passageways are permitted to use Class C wainscotting or paneling in the grade
lobby for not more than 1,000 square feet of applied surface when applied to a noncombustible base.
Figure 25: Summary of Table 803.11 Interior Wall and Finish Requirements by Occupancy
Nonsprinklered Buildings: Minimum Interior Finish Classification by Occupancya
Location
Minimum Interior Finish Classification
Ab
B C
Exit enclosures and exit
passagewaysc
A, B, E, I, M,
R-1, R-4
F, S, R-2 R-3
Corridors Ad
, I-2, I-3, I-4
B, E, M, S, I-1, R-1,
R-2, R-4
F, R-3
Enclosed spaces and rooms I, A-1e
, A-2e
,
R-4
A-3, A-4, A-5, B, E, F,
M, S, R-1, R-2, R-3
Sprinklered Buildings: Minimum Interior Finish Classification by Occupancya, b
Location
Minimum Interior Finish Classification
A Bc
C
Exit enclosures and exit
passagewaysd I-3 A, B, E, M, R-1, R-4, I-1, I-2, I-4 F, R-2, R-3, S
Corridors I-3 A, I-2, I-4 B, E, F, M, R, S, I-1
Enclosed spaces and rooms I-2, I-4 A, B, E, F, M, R, S, I-1, I-3
Figure 24: Wood Interior Finish
(Photo Courtesy of Barbara J Sales)

Most wood species qualify as Class C, while some, such as cedar, west coast hemlock, Idaho
white pine, redwood, and spruce, can qualify as Class B. Wood boards and panels may meet Class
A criteria when pressure treated with a fire-retardant chemical. Flame spread information
according to wood species is provided in AWC DCA 1, Flame Spread Performance of Wood Prod-
ucts, which is available for free to download at
Traditional wood floor covering is exempt from interior floor finish requirements (Section
804.1). Exposed portions of Type IV structural members are also exempt from the interior finish
requirements (Sections 803.3).
Wood Interior Trim
Baseboards, chair rails, picture molding, handrails, guards, win-
dows and doors are permitted to be wood or wood-based materi-
als. Trim is required to meet a Class C classification and
combustible trim, excluding handrails and guards, cannot exceed
10 percent of the wall or ceiling area to which it is attached (Sec-
tion 806.7).
Wood Doors and Windows
Wood doors and windows are often the optimum choice for
buildings due to their aesthetics, energy efficiency and functional-
ity. Exterior openings are generally required to be protected as an
opening protective assembly when the exterior wall is within
given distances of a lot line. Table 602 determines when the exte-
rior walls are required to be fire-resistance rated due to their loca-
tion on the lot, and Table 705.8 defines the allowable percentages
of protected and unprotected openings allowed in those walls.
Unlimited amounts of unprotected openings are permitted by
Table 705.8, provided the exterior walls are 30 feet or more from the lot line, or 20 feet or more
if the building is equipped throughout with an automatic sprinkler system. No unprotected open-
ings are permitted in the exterior wall within 5 feet of the lot line for nonsprinklered buildings or
in any building if the wall is closer than 3 feet from the lot line.
Bay and oriel windows must conform to the type of construction required for the building;
however, FRTW is permitted for these windows in buildings not more than three stories above
grade plane and of Type I, II, III and IV construction (Section 1406.4).
Interior wood door assemblies are required to be fire-protection rated when the wall assembly
they are in requires a fire-resistance rating and opening protection, such as door assemblies in
exit enclosures or exit access corridor walls. The minimum required fire-protection rating of the
fire door assembly is given in Table 716.5 and ranges from 20 minutes to 3 hours based on the
required fire-resistance rating and type of wall assembly.
Figure 26: Wood Trim
Figure 27: Wood Windows

Wood Siding
Wood siding products come in a variety of sizes, shapes and
textures, ranging from wood shingles and shakes to boards and
wood structural panels. Each material brings different charac-
teristics in look and performance. The IBC addresses the mini-
mum expectations of these products in Chapter 14 as exterior
wall components and Chapter 23 as a wood building material.
Wood shingles as a weather covering are required to be a
minimum 3
/8-inch thick and wood siding without sheathing is
required to be 1
/2-inch thick. According to Table 1405.2, wood siding less than 1
/2-inch thick
requires bracing for support in accordance with Section 2304.6.
Wood Veneer
Wood veneer is permitted on buildings of Type I, II, III or
IV construction and allowed up to 40 feet above grade, 60
feet if FRTW is used provided the veneer is 1-inch nominal
thickness, 7
/16-inch exterior hardboard siding or 3
/8-inch exte-
rior-type wood structural panels or particleboard. Open or
spaced veneers without concealed spaces are not permitted
to project more than 24 inches from the building wall (Sec-
tion 1405.5).
Wood Balconies, Open Exterior Exit Stairs and
Ramps
Exterior balconies may be of Type IV construc-
tion or of wood construction that provides a fire-
resistance rating equal to the floor rating
required by Table 601. The aggregate length of
the balcony is limited to 50 percent of the build-
ing perimeter on each floor. Type I or II struc-
tures not more than three stories above grade
plane are permitted to have FRTW in the balcony
as long as the balcony is not a required exit. Type
III, IV and V buildings may have Type V construc-
tion of the balcony without requiring a fire-resis-
tance rating if the balcony is sprinkler protected.
Where sprinkler protection is extended to the
balcony, the length limitation of the balcony is eliminated (Section 1406.3).
Open exterior exit stairs and ramps may be constructed of wood when the building is of Type
IV and V construction (Sections 1011.7 and 1012.7). The IBC limits their use to buildings that do
not exceed six stories above grade and do not have occupied floor levels located more than 75
feet above the lowest level of vehicular access by the fire department (Section 1027.2).
Figure 28: Wood Siding
Figure 29: Wood Veneer
(Photo Courtesy of Jeremy Bittermann)
Figure 30: Wood Balcony

Wood Roof Coverings
Roof assemblies and coverings are divided into
classifications in accordance with testing by the
ASTM E108 or UL 790 standard. FRTW roof cov-
erings are tested in accordance with the ASTM
D2898 standard. Table 1505.1 requires a mini-
mum Class B roof covering for all types of con-
struction except Type IIB, IIIB and VB. These
construction types are permitted a minimum of
Class C materials, and if the buildings are not
more than two stories above grade plane and
have no more than 6,000 square feet of roof
area and 10-foot minimum frontage width on all sides of the roof, they are permitted to use No.
1 cedar or redwood shakes and No. 1 shingles (Table 1505.1).
Fire-retardant-treated wood shingles and shakes can qualify for Class A, B or C classification.
Wood shingles and wood shake installation requirements are located in Sections 1507.8 and
1507.9, respectively, with a comparison of the materials in Table 1507.8.
Wood Projection Limitations
Regardless of the material used or the construction type, Section 705.2 places limits on the
proximity of projections to the line used to calculate fire separation distance (typically the lot
line). According to Table 705.2, in no case may a projection come within 24 inches of a lot line.
When the fire separation distance from the exterior wall is 30 feet or greater, projections cannot
come within 20 feet of the lot line; when the fire separation distance is 2 feet or less, projections
are prohibited altogether.
In Type III, IV, and V construction, projections of any material are permitted subject to the lim-
itation of Section 705.2.3. That section says that combustible projections located within 5 feet of
the lot line (or other line used to determine the fire separation distance) must be one of the fol-
lowing:
• Minimum 1-hour fire-resistance-rated construction;
• Type IV construction; or
• FRTW.
Note that the exception in Section 705.2.3 allows projections in Group R-3 and U occupancies
to be of typical Type VB construction (protection in the form of rated construction, Type IV con-
struction, or FRTW is not required) when the fire separation distance is greater than or equal to 5
feet.
Figure 31: Wood Shakes

Figure 32: Wood Projection Limitations for Other Than Groups R-3 and U
Wood Rooftop Structures
Wood penthouses are limited by the construction classification permitted for the building and
for purposes of height and area are considered a portion of the story below the penthouse as
long as they comply with Section 1510. FRTW is permitted for use on buildings of Type I con-
struction two stories or less above grade plane and in Type II construction when the exterior of
the penthouse is 5 feet or more from lot lines in accordance with Section 1510.2.5. A 1-hour fire-
resistance rating is required when the exterior wall of the penthouse is less than 20 feet from the
lot line.
Type III, IV and VA construction permit the penthouse to be Type IV construction or FRTW if 20
feet or more from the lot line.
Wood penthouses used to enclose tanks or elevators must not exceed 28 feet in height above
the roof. If enclosing other uses, the penthouse height is limited to 18 feet maximum (Section
1510.2.1).
Wood unroofed mechanical equipment screens, fences or enclosures limited to 4 feet in height
are permitted (Section 1510.6.2).
Wood towers, spires, domes and cupolas are permitted on buildings of Type III, IV and V pro-
vided that they do not exceed 85 feet in height above grade plane or 200 square feet in area. The
IBC places further limitations on these structures in Section 1510.5.
Wood in Locations Subject to Decay or Termites
Wood that is located where it will be exposed to weather, moisture or termites is required to
be naturally durable wood species or preservative-treated wood using water-borne preserva-
tives, in accordance with AWPA U1. Naturally durable decay-resistant wood species are heart-
woods of redwood, cedar, black locust and black walnut. Naturally durable termite-resistant
wood species are heartwood of redwood, Alaska yellow-cedar, eastern red cedar and heartwood
and sapwood of all western red cedars (Sections 202 and 2304.12).
No projections
permitted
FRTW, Type IV or
1-hr min fire rating
No protection required unless
projection extends to within 5 feet
of the line used for FSD
Lot Line
Lot Line
Exterior Face of
Exterior Wall
Exterior Face of
Exterior Wall
Edge of
Projection
Edge of
Projection24″ min
24″ plus 8″ for every
foot beyond 3′ min.
> 2′ to ≤3′ (FSD) >3′ to <30′ (FSD)
Lot Line
0′ to 2′(FSD)
Exterior Face of
Exterior Wall
No protection
required
Lot Line
Exterior Face of
Exterior Wall
Edge of
Projection 20′ minimum
≥30′ (FSD)

7. Structural Considerations
The primary focus of Chapter 23 of the IBC is structural considerations for the design of build-
ings and structures that use wood and wood-based products in their framing and fabrication.
Covered are the materials, design, construction and quality of wood members and their fasten-
ers. Alternative methods and materials can be used where engineering analysis and testing jus-
tify their use; however, the general requirements of Section 2304 apply to all elements of wood
frame construction. New products included in the 2015 IBC are Structural Glued Cross-Laminated
Timber and Engineered Wood Rim Board.
Compliance Paths
The IBC permits five paths to design wood structural elements, and com-
pliance with one or more is required (Section 2301.2):
• Allowable Stress Design (ASD)
• Load and Resistance Factor Design (LRFD)
• Conventional Light-Frame Construction
• AWC Wood Frame Construction Manual (WFCM)
• ICC 400 for Log Structures
The first two methods are engineered design. Allowable stress design
(ASD) prescribes the use of load combinations specified in Chapter 16 as well as the general
requirements in Section 2304, the lateral force resistance requirements in Section 2305, and the
ASD requirements of Section 2306. Load and resistance factor design (LRFD), permitted by Sec-
tion 2307, also requires the use of the load combinations in Chapter 16, the general require-
ments in Section 2304, and the lateral force resistance requirements in Section 2305.
The descriptive and prescriptive provisions of the conventional light-frame construction in Sec-
tion 2308 use typical configurations and methods that do not require calculation of loads or anal-
ysis by a design professional. The use of these provisions is limited to buildings of relatively small
volume that do not incorporate unusual configurations, elements, or loading.
The AWC Wood Frame Construction Manual for One- and Two-Family Dwellings (AWC WFCM)
and ICC 400, Standard on the Design and Construction of Log Structures, are also permitted as
design and construction alternatives for buildings within their scopes.
Standards and Quality
Section 2303 references manufacturing standards, necessary specification criteria and use and
application provisions for wood and wood products. The materials that have production and
quality control standards include structural sawn lumber; end-jointed lumber; prefabricated
wood I-joists; structural glued-laminated timber (defined in IBC Chapter 2); structural glued
cross-laminated timber (defined in IBC Chapter 2); wood structural panels (defined in IBC Chap-
ter 2); fiberboard sheathing (when used structurally); hardboard siding (when used structurally);
particleboard; preservative-treated and fire-retardant-treated wood (defined in IBC Chapter 2
under “Treated wood”); structural log members; structural composite lumber; round timber
poles and piles; engineered wood rim board (defined in IBC Chapter 2); wood trusses; joist hang-
ers; nails; and staples.
All lumber used to support loads in a building or structure is required to be properly identified
with a grade mark of a lumber inspection agency complying with DOC PS 20, the American Soft-
wood Lumber Standard (see www.alsc.org for a list of grading agencies and representative grade
Figure 33: WFCM

stamps). A certificate of inspection is an acceptable alternative to a grade mark for precut,
remanufactured or rough-sawn lumber and for sizes larger than 3-inch nominal thickness, since
industry practice does not individually label such products.
Engineered wood products, preservative-treated wood, and fire-retardant-treated wood are
required to meet industry standards specific to their use, as codified within this section.
Framing
The general requirements of Section 2304 govern framing, sheathing, decking and fasteners.
It is worth noting that conventional light-frame construction does not require computations to
determine the size of members or fasteners; however, ASD and LRFD designs assume actual
member sizes rather than nominal sizes. Under the majority of circumstances, the detail and
specifications for framing walls, roofs, and floors in accordance with Section 2308 provide the
necessary resistance to typical loading conditions. Section 2304.3 specifies that bottom plates
are required to have a minimum thickness of a nominal 2-by framing member with a width at
least equal to the stud it is supporting in order to ensure loads are fully transferred.
Structural Panels and Sheathing
Wood structural panels are defined in Chapter 2 as being plywood, oriented strand board
(OSB), and composite panels. Exterior sheathing is required to be manufactured with exterior
glue (Exposure 1 or Exterior) and, when exposed to the weather, to have an exterior exposure
durability classification. In enclosed buildings with a mean roof height not greater than 30 feet,
wood structural panel sheathing, connections, and framing spacing must meet the wind design
requirements of Table 2304.6.1. Tables 2304.8(1) through (5) specify maximum allowable spans,
minimum grade requirements, and maximum loads for floor and roof sheathing.
Lumber Decking
Section 2304.9 provides installation and fastening require-
ments for lumber decking, which is a method of floor con-
struction that employs individual wood members set on edge
and connected. Each piece of lumber is required to be
square-end trimmed and supported in one of five layup pat-
terns: simple span, two-span continuous, combination simple
and two-span continuous, cantilevered pieces intermixed, or
controlled random (Section 2304.9.2). Section 2304.9.3 pre-
scribes nailing requirements for mechanically laminated
decking to ensure a solid wood floor acting as one element.
Connectors and Fasteners
Fastening requirements are prescribed in Table 2304.10.1, which provides the minimum num-
ber and size of fasteners connecting wood members. Additionally, the ASD and LRFD methods
contain design provisions for fasteners, based on design calculations, which must be met in
accordance with Section 2304.10. It is therefore common for designed structures to have
greater fastening requirements than those prescribed in Table 2304.10.1. Where wall framing
members are not continuous from the foundation sill to the roof, sheet metal clamps, ties or
clips must also be corrosion resistant (often galvanized steel) if they are subject to moisture.
Figure 34: Beam-Column Connection

Joist and framing anchors may be used in accordance with the manufacturer’s instructions, and
other fasteners such as clips, staples, and glues are permitted when approved by the building
official. Such approval should be based on evidence of testing by the manufacturer and installa-
tion in accordance with the manufacturer’s specifications.
Fasteners in contact with preservative-treated and fire-retardant-treated wood are required to
be corrosion resistant (often of hot-dipped zinc-coated galvanized steel, stainless steel, silicon
bronze or copper in accordance with Section 2304.10.5) because chemicals used in the treat-
ments quickly erode untreated steel fasteners.
Lateral Force-Resisting Systems
The general design requirements for lateral force-resisting systems in Sec-
tion 2305 are applicable to engineered structures (ASD and LRFD). This sec-
tion applies to structures using wood-framed shear walls or wood-framed
diaphragms to resist wind, seismic, or other lateral loads. When individual
elements within conventionally constructed structures need to be engi-
neered, these provisions may be able to be applied without engineering the
entire structure.
Deflection of wood diaphragms and shear walls fastened with nails is
determined in accordance with AWC Special Design Provisions for Wind and Seismic (AWC
SDPWS). For wood structural diaphragms and shear walls fastened with staples, where the
assemblies are uniformly fastened throughout, the IBC permits the calculation of estimates
through the use of the equations found in Sections 2305.2 and 2305.3.
Engineered Design—Allowable Stress and Load and Resistance Factor
Sections 2306 and 2307 contain a number of specifications that are intended to be the mini-
mum acceptable methods for constructing wood elements in structures. When designed and
built in accordance with the standards listed in these sections, a building or structure is deemed
to comply with the code. The most common and applicable practices for ASD are summarized in
the standards listed in Section 2306.1, and Section 2307.1 refers the code user to AWC National
Design Specification® (NDS®) for Wood Construction and AWC SDPWS for alternate design provi-
sions using LRFD.
Conventional Light Frame
The provisions of Section 2308 are prescriptive in nature and can be used to construct certain
wood structures in limited application—generally building construction having closely spaced
framing (not exceeding 24 inches on center) with studs up to 2 x 6 inches in size and rafters up to
2 x 12 inches in size. Section 2308.2 and its subsections spell out the limitations for the use of
conventional construction provisions without design. These include height limits ranging from
one story in Seismic Design Categories D and E to three stories in Categories A and B; a maximum
floor-to-floor height of 11 feet, 7 inches in all seismic zones; exterior bearing walls and interior
bracing walls limited to a stud height of 10 feet; live loads not exceeding 40 psf; ultimate wind
speeds (Vult) not exceeding 130 mph; and others (see Section 2308.2 for the full list).
Figure 35: SDPWS

Span Tables
Span tables are provided for girders, floor joists, ceiling joists, and
rafters in Tables 2308.4.1.1(1)–(2), 2308.4.2.1(1)–(2), 2308.7.1(1)–(2),
and 2308.7.2(1)–(6), respectively. These spans have been updated to
reflect the recently revised Southern Pine design values. Spans of only
the most common species and grades of wood are shown, and the
tables in the AWC Span Tables for Joists and Rafters (STJR) should be
consulted to determine spans for species and grades not shown. See
Section 2308.7.7 for how the use of purlins and struts allows the reduc-
tion of rafter spans. An excerpt of Table 2308.4.2.1(1) is shown in Fig-
ure 37.
Figure 37: Excerpt of Table 2308.4.2.1(1) Floor Joist Spans for Common Lumber Species
(Residential sleeping areas, live load = 30 psf, L/Δ = 360)
See Sections 2308.4 and 2308.7 for prescriptive framing details for floors and roofs, including
required bearing, lateral support, notches and holes, and framing around openings.
Wind Uplift
Section 2308.7.5 requires compliance with both Table 2304.10.1, which is the fastening sched-
ule, and Table 2308.7.5, which specifies the minimum uplift resistance to be provided between
the roof framing and wall below in conventional construction. For allowable stress design wind
speeds (Vasd) of less than 85 mph ties are not required. When ties are required by the table, a tie
is required on every rafter or truss to the stud below, assuming the roof framing is spaced 24
inches on center, in accordance with Table 2308.7.5, Footnote b.
Joist
Spacing
(inches)
Species and
Grade
DEAD LOAD = 10 psf DEAD LOAD = 20 psf
2 × 6 2 × 8 2 × 10 2 × 12 2 × 6 2 × 8 2 × 10 2 × 12
Maximum floor joist spans
(ft. - in.) (ft. - in.) (ft. - in.) (ft. - in.) (ft. - in.) (ft. - in.) (ft. - in.) (ft. - in.)
16
Douglas Fir-Larch SS 11-4 15-0 19-1 23-3 11-4 15-0 19-1 23-0
Douglas Fir-Larch #1 10-11 14-5 18-5 21-4 10-8 13-6 16-5 19-1
Hem-Fir SS 10-9 14-2 18-0 21-11 10-9 14-2 18-0 21-11
Hem-Fir #1 10-6 13-10 17-8 20-9 10-4 13-1 16-0 18-7
Hem-Fir #2 10-0 13-2 16-10 19-8 9-10 12-5 15-2 17-7
Hem-Fir #3 8-5 10-8 13-0 15-1 7-6 9-6 11-8 13-6
Southern Pine SS 11-2 14-8 18-9 22-10 11-2 14-8 18-9 22-10
Southern Pine #1 10-9 14-2 18-0 21-4 10-9 13-9 16-1 19-1
Southern Pine #2 10-3 13-3 15-8 18-6 9-4 11-10 14-0 16-6
Southern Pine #3 7-11 10-10 12-1 14-4 7-1 8-11 10-10 12-10
Spruce-Pine-Fir SS 10-6 13-10 17-8 21-6 10-6 13-10 17-8 21-4
Spruce-Pine-Fir #1 10-3 13-6 17-2 19-11 9-11 12-7 15-5 17-10
Spruce-Pine-Fir #2 10-3 13-6 17-2 19-11 9-11 12-7 15-5 17-10
Spruce-Pine-Fir #3 8-5 10-8 13-0 15-1 7-6 9-6 11-8 13-6
Figure 36: STJR

Wall Framing
The size, height and spacing of studs are required to be in accordance with Table 2308.5.1.
When stud heights exceed 10 feet or the structure is outside the scope of applicability of the con-
ventional construction requirements, studs must be designed in accordance with accepted engi-
neering practice. Studs in nonload-bearing walls and partitions are permitted to be spaced at 24
inches on center.
Section 2308.5 and subsections contain prescriptive framing provisions for walls. Generally,
bearing and exterior wall studs are required to be capped with overlapping double top plates,
which serves three major functions: the overlapping plates tie the building together, the top
plates serve as support beams for joists and rafters, and they serve as chords for floor and roof
diaphragms. The single bottom plate serves to anchor the wall to the floor and must have a nom-
inal thickness of not less than 2 inches and a width not less than the width of the wall studs.
Openings in exterior bearing walls require headers made of double 2-inch nominal framing lum-
ber.
Wall Bracing
Braced wall panels are portions of walls, as required
by Table 2308.6.1, composed of bracing materials and
methods specified in Table 2308.6.3(1). Section
2308.6.4 stipulates the minimum panel dimensions for
certain bracing methods. A provision exists allowing a
minimum 32-inch wall bracing length in lieu of the 48-
inch length required elsewhere, or a minimum 16-inch
panel length built as a portal, to allow flexibility in con-
structing braced wall panels adjacent to garage doors
and other similar openings (Section 2308.6.5). Cripple
walls with studs exceeding 14 inches in height must
meet the bracing requirements (Section 2308.6.6).
8. Precautions during Construction
Chapter 33 provides minimum safety precautions for fire during construction for all buildings.
The chapter includes provisions for fire extinguishers, standpipes, means of egress and sprinkler
system commissioning. The International Fire Code® (IFC®) also contains detailed requirements
for fire precautions during construction that are required to be implemented by Section 3302.3 of
the IBC.
Fire Extinguishers
During construction one portable fire extinguisher must be placed at each stairway on all floor
levels with combustible materials, in each storage or construction shed, and where special haz-
ards exist in accordance with Section 3309.
Maintaining Means of Egress
During construction, when a building height reaches 50 feet or four stories, a minimum of one
temporary lighted stairway must be provided unless a permanent stairway is available for use at
all times in accordance with Section 3310.
Figure 38: Wall Bracing

Standpipes
In buildings required to have standpipes, a minimum of one must be available during construc-
tion for fire department use. The standpipe is installed before the construction is 40 feet above
fire department access. The standpipe is placed adjacent to usable stairs and has fire department
hose connections. It must be extended during construction to within one floor of the highest
point of construction having flooring in accordance with Section 3311. During demolition, a
standpipe is maintained in working condition. The standpipe may be demolished floor by floor as
demolition proceeds.
Sprinkler System Commissioning
The sprinkler system must be tested and approved before the certificate of occupancy is
awarded in accordance with Section 3312.
Additional requirements in the International Fire Code
Additional requirements for fire safety during construction required by IBC Section 3302.3 but
found in the IFC are as follows:
• Temporary heating equipment must be listed and labeled; installation and mainte-
nance of the equipment must be in accordance with the listing (IFC Section 3303).
• Smoking is prohibited except in approved areas with posted signage (IFC Section
3304.1).
• A fire watch must be maintained with qualified personnel if required by the fire code
official (IFC Section 3304.5).
• Welding operations must comply with IFC Chapter 35. Temporary electrical wiring
must comply with NFPA 70 (IFC Sections 3304.6 and 3304.7).
• The owner must designate a fire prevention superintendent responsible for the fire
prevention program during construction. Requirements for the program are listed in
IFC Section 3308.
• An accessible emergency phone must be provided in an approved location at the con-
struction site. The construction site street address and fire department emergency
phone number must be posted by the phone (IFC Section 3309).
• Fire-fighting vehicle access must be provided within 100 feet of temporary or perma-
nent fire department connections (IFC Section 3310).
• An approved water supply for fire protection must be available (IFC Section 3312).
• Safeguards during roofing operations must be in accordance with IFC Section 3317.

9. Resources
For additional assistance and information, contact the American Wood Council (AWC) at
(202) 463-2766 or info@awc.org. For additional assistance and information from the Interna-
tional Code Council (ICC), see www.iccsafe.org.
American Wood Council Standards
The above standards published by AWC are referenced in the IBC. These standards and related
code publications, design aids, technical reports and guides for wood design and construction
can be purchased or downloaded at www.awc.org.
ANSI/AWC NDS®
2015 National Design Specification®
(NDS®
) for Wood Construction with 2015 Supplement
ANSI/AWC
SDPWS
2015 Special Design Provisions for Wind and Seismic
ANSI/AWC WFCM 2015 Wood Frame Construction Manual for One- and Two-Family Dwellings
ANSI/AWC PWF 2015 Permanent Wood Foundation Design Specification
AWC STJR 2015 Span Tables for Joists and Rafters
AWC WCD No. 4 2003 Wood Construction Data—Plank and Beam Framing for Residential Buildings

Other Associations Publishing Referenced Standards
Standards from additional organizations are referenced in this publication. The following table
lists the standard, its title and the site from which the standard is available.
This publication was developed by the International Code Council in cooperation with the
American Wood Council. While every effort was made to ensure accuracy of the information it
contains, neither organization assumes responsibility for particular designs or plans prepared
from this document.
Standard-Edition Title Website
AAMA/WDMA/CSA
101/I.S.2/A440-11
North American Fenestration Standard/
Specifications for Windows, Doors and Skylights
aamanet.org
wdma.com
APA PDS—12 Panel Design Specification apawood.org
ASCE 7-10 Minimum Design Loads for Buildings and Other Structures asce.org
ASTM D2898-10
Test Methods for Accelerated Weathering of Fire-Retardant-Treated
Wood Fire Testing
astm.orgASTM E84-13a Test Methods for Surface Burning Characteristics of Building Materials
ASTM E108-11 Test Methods for Fire Tests of Roof Coverings
ASTM E119-12 Test Methods for Fire Tests of Building Construction and Materials
AWPA C1-03 All Timber Products—Preservative Treatment by Pressure Processes
awpa.com
AWPA M4-11 Standard for the Care of Preservative-Treated Wood Products
AWPA U1-14
USE CATEGORY SYSTEM: User Specification for Treated Wood
Except Section 6, Commodity Specification H
2015 IBC 2015 International Building Code
iccsafe.org
2015 IRC 2015 International Residential Code
ICC 400-12 Standard on Design and Construction of Log Structures
ICC 600-14 Standard for Residential Construction in High-Wind Regions
NFPA 13-13 Installation of Sprinkler Systems
nfpa.org
NFPA 13D-13
Installation of Sprinkler Systems in One- and Two-Family Dwellings and
Manufactured Homes
NFPA 13R-13 Installation of Sprinkler Systems in Low-Rise Residential Occupancies
NFPA 70-14 National Electrical Code
UL 263-11 Standard for Fire Tests of Building Construction and Materials
ul.com
UL 723-08
Standard for Test for Surface Burning Characteristics of Building
Materials, with revisions through September 2010
UL 790-04
Standard Test Methods for Fire Tests of Roof Coverings with revisions
through October 2008

10. Building Area Tables
These tables are organized by occupancy category. Each category has a nonsprinklered and
sprinklered allowable building area table that contains the maximum number of stories and max-
imum allowable area per floor for Type IIIA and IIIB, IV, VA and VB construction.
Table 1 – Group A Nonsprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
a. Frontage based on open space widths of 30 feet or more.
b. Interpolation permitted.
c. Sprinklers must be provided for Group A-1, A-3 and A-4 occupancies when the fire area exceeds 12,000
square feet in accordance with Section 903.2.1, or by reason of other specific conditions in that section. In
lieu of sprinklers, compartmentalization of the floor area into fire areas not more than 12,000 square feet can
be provided with fire-resistance-rated construction in accordance with Chapter 7.
d. Sprinklers must be provided for Group A-2 occupancies when the fire area exceeds 5,000 square feet in
accordance with Section 903.2.1.2, or by reason of other specific conditions in that section. In lieu of sprin-
klers, compartmentalization of the floor area into fire areas not more than 5,000 square feet can be provided
with fire-resistance-rated construction in accordance with Chapter 7.
e. Sprinklers must be provided for Group A-5 occupancies when the area exceeds 1,000 square feet in accor-
dance with Section 903.2.1.5.
f. Type VB construction does not permit two stories above grade plane.
Group A-1 Nonsprinklered Buildings a, b, c
# of stories % frontage
Maximum floor area per story (sq. ft.)
IIIA IIIB IV VA VB
1, 2f
0-25 14,000 8,500 15,000 11,500 5,500
50 17,500 10,620 18,750 14,370 6,870
100 24,500 14,870 26,250 20,120 9,620
3
0-25 14,000 NP 15,000 NP NP
50 17,500 NP 18,750 NP NP
100 24,500 NP 26,250 NP NP
Groups A-2, A-3, A-4 Nonsprinklered Buildings a, b, c, d
IIIA IIIB IV VA VB
1, 2f
0-25 14,000 9,500 15,000 11,500 6,000
50 17,500 11,870 18,750 14,370 7,500
100 24,500 16,620 26,250 20,120 10,500
3
0-25 14,000 NP 15,000 NP NP
50 17,500 NP 18,750 NP NP
100 24,500 NP 26,250 NP NP
Group A-5 Nonsprinklered Buildings a, e
IIIA IIIB IV VA VB
UL
0-25 UL UL UL UL UL
50 UL UL UL UL UL
100 UL UL UL UL UL

Table 2 – Group A NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
a. The maximum floor area for four stories above grade plane was determined by dividing the maximum total
allowable building area determined in accordance with Section 506.2.3 by the number of stories. The floor
area of the four stories is assumed to be equal.
b. Frontage based on open space widths of 30 feet or more.
c. Interpolation permitted.
d. Type VB construction does not permit three stories above grade plane.
e. Group A-1 and A-2 occupancies may be in unlimited area mixed occupancy buildings when meeting the pro-
visions of Section 507.4.1.
f. Group A-4 may be unlimited in area if the frontage width is at least 60 feet and the building is of Type III or
IV construction in accordance with Section 507.4.
Group A-1 Sprinklered Buildingsa, b, c
IIIA IIIB IV VA VB
1
0-25 56,000 34,000 60,000 46,000 22,000
50 59,500 36,120 63,750 48,870 23,370
100 66,500e
40,370 e
71,250 e
54,620 26,120
2, 3d
0-25 42,000 25,500 45,000 34,500 16,500
50 45,500 27,620 48,750 37,370 17,870
100 52,500 31,870 56,250 43,120 20,620
4
0-25 31,500 NP 33,750 NP NP
50 34,120 NP 36,560 NP NP
100 39,370 NP 42,180 NP NP
Group A-2, A-3, A-4 Sprinklered Buildings a, b, c
IIIA IIIB IV VA VB
1
0-25 56,000 38,000 60,000 46,000 24,000
50 59,500 40,370 63,750 48,870 25,500
100 66,500e,f
45,120e,f
71,250e,f
54,620 28,500
2, 3d
0-25 42,000 28,500 45,000 34,500 18,000
50 45,500 30,870 48,750 37,370 19,500
100 52,500 35,620 56,250 43,120 22,500
4
0-25 31,500 NP 33,750 NP NP
50 34,120 NP 36,560 NP NP
100 39,370 NP 42,180 NP NP
Group A-5 Sprinklered Buildings b
IIIA IIIB IV VA VB
UL
0-25 UL UL UL UL UL
50 UL UL UL UL UL
100 UL UL UL UL UL

Table 3 – Group B Nonsprinklered Buildings – Maximum floor area per story a, b, c, d
NP = Not Permitted
a. The maximum floor area for four or more stories above grade plane was determined by dividing the maxi-
mum total allowable building area determined in accordance with Section 506.2.3 by the number of stories.
The floor area of the stories is assumed to be equal.
d. Sprinklers must be provided for ambulatory care facilities in accordance with Section 903.2.2.
e. Type VB construction does not permit three stories above grade plane.
IIIA IIIB IV VA VB
1, 2 & 3e
0-25 28,500 19,000 36,000 18,000 9,000
50 35,620 23,750 45,000 22,500 11,250
100 49,870 33,250 63,000 31,500 15,750
4
0-25 21,370 NP 27,000 NP NP
50 26,710 NP 33,750 NP NP
100 37,400 NP 47,250 NP NP
5
0-25 17,100 NP 21,600 NP NP
50 21,370 NP 27,000 NP NP
100 29,920 NP 37,800 NP NP

Table 4 – Group B NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story a, b, c
NP = Not Permitted
UL = Unlimited
d. Sprinklered Group B buildings of one or two stories may be unlimited in area if the frontage width is at least
60 feet in accordance with Sections 507.4 and 507.5.
IIIA IIIB IV VA VB
1
0-25 114,000 76,000 144,000 72,000 36,000
50 121,120 80,750 153,000 76,500 38,250
100 135,370 90,250 171,000 85,500 42,750
100 (60’)d
UL UL UL UL UL
2
0-25 85,500 57,000 108,000 54,000 27,000
50 92,620 61,750 117,000 58,500 29,250
100 106,870 71,250 135,000 67,500 33,750
100 (60’) d
UL UL UL UL UL
3
0-25 85,500 57,000 108,000 54,000 27,000
50 92,620 61,750 117,000 58,500 29,250
100 106,870 71,250 135,000 67,500 33,750
4
0-25 64,120 42,750 81,000 40,500 NP
50 69,460 46,310 87,750 43,870 NP
100 80,150 53,430 101,250 50,620 NP
5
0-25 51,300 NP 64,800 NP NP
50 55,570 NP 70,200 NP NP
100 64,120 NP 81,000 NP NP
6
0-25 42,750 NP 54,000 NP NP
50 46,310 NP 58,500 NP NP
100 53,430 NP 67,500 NP NP

Table 5 – Group E Nonsprinklered Buildings – Maximum floor area per story a, b, c
NP = Not Permitted
c. Sprinklers must be provided for Group E occupancies when the fire area exceeds 12,000 square feet in accor-
dance with Section 903.2.3, or by reason of other specific conditions in that section. In lieu of sprinklers,
compartmentalization of the floor area into fire areas not more than 12,000 square feet can be provided with
fire-resistance-rated construction in accordance with Chapter 7.
Table 6 – Group E NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story a, b, c
NP = Not Permitted
area of the stories is assumed to be equal.
d. Types VA and VB construction do not permit three stories above grade plane.
e. Single-story Group E buildings may be of unlimited area when meeting the requirements of Section 507.11.
IIIA IIIB IV VA VB
1
0-25 23,500 14,500 25,500 18,500 9,500
50 29,370 18,120 31,870 23,120 11,870
100 41,120 25,370 44,620 32,370 16,620
2
0-25 23,500 14,500 25,500 NP NP
50 29,370 18,120 31,870 NP NP
100 41,120 25,370 44,620 NP NP
3
0-25 23,500 NP 25,500 NP NP
50 29,370 NP 31,870 NP NP
100 41,120 NP 44,620 NP NP
IIIA IIIB IV VA VB
1
0-25 94,000 58,000 102,000 74,000 38,000
50 99,870 61,620 108,370 78,620 40,370
100 111,620e
68,870 121,120e
87,870 45,120
2, 3d
0-25 70,500 43,500 76,500 55,500 28,500
50 76,370 47,120 82,870 60,120 30,870
100 88,120 54,370 95,620 69,370 35,620
4
0-25 52,870 NP 57,370 NP NP
50 57,280 NP 62,150 NP NP
100 66,090 NP 71,710 NP NP

Table 7 – Group F Nonsprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
d. Sprinklers must be provided in woodworking areas in Group F-1 occupancies when the fire area exceeds
2,500 square feet in accordance with Section 903.2.4.1 and when areas manufacturing upholstered furniture
or mattresses exceed 2,500 square feet in accordance with Section 903.2.4.
e. Sprinklers must be provided for Group F-1 occupancies when the fire area exceeds 12,000 square feet, or the
combined area of all Group F-1 occupancies exceeds 24,000 square feet, in accordance with Section 903.2.4,
or by reason of other specific conditions in that section. In lieu of sprinklers, compartmentalization of the
floor area into fire areas not more than 12,000 square feet per compartment and not more than 24,000 square
feet total can be provided with fire-resistance-rated construction in accordance with Chapter 7.
f. Type VB construction does not permit two stories above grade plane.
g. Type VB construction does not permit three stories above grade plane.
h. Single-story Group F-2 occupancies may be unlimited in area if the frontage width is at least 60 feet in accor-
Group F-1 Nonsprinklered Buildings a, b, c, d, e
# of stories % frontage IIIA IIIB IV VA VB
1, 2f
0-25 19,000 12,000 33,500 14,000 8,500
50 23,750 15,000 41,870 17,500 10,620
100 33,250 21,000 58,620 24,500 14,870
3
0-25 19,000 NP 33,500 NP NP
50 23,750 NP 41,870 NP NP
100 33,250 NP 58,620 NP NP
4
0-25 NP NP 25,120 NP NP
50 NP NP 31,400 NP NP
100 NP NP 43,960 NP NP
Group F-2 Nonsprinklered Buildings a, b, c
IIIA IIIB IV VA VB
1
0-25 28,500 18,000 50,500 21,000 13,000
50 35,620 22,500 63,120 26,250 16,250
100 49,870 31,500 88,370 36,750 22,750
100 (60’)h
UL UL UL UL UL
2 & 3g
0-25 28,500 18,000 50,500 21,000 13,000
50 35,620 22,500 63,120 26,250 16,250
100 49,870 31,500 88,370 36,750 22,750
4
0-25 21,370 NP 37,870 NP NP
50 26,710 NP 47,340 NP NP
100 37,400 NP 66,280 NP NP
5
0-25 NP NP 30,300 NP NP
50 NP NP 37,870 NP NP
100 NP NP 53,020 NP NP

Table 8 – Group F NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
d. Sprinklered Group F buildings of one or two stories may be unlimited in area if the frontage width is at least
Group F-1 Sprinklered Buildings a, b, c
IIIA IIIB IV VA VB
1
0-25 76,000 48,000 134,000 56,000 34,000
50 80,750 51,000 142,370 59,500 36,120
100 90,250 57,000 159,120 66,500 40,370
100(60’)d
UL UL UL UL UL
2
0-25 57,000 36,000 100,500 42,000 25,500
50 61,750 39,000 108,870 45,500 27,620
100 71,250 45,000 125,620 52,500 31,870
100(60’)d
UL UL UL UL UL
3
0-25 57,000 36,000 100,500 42,000 NP
50 61,750 39,000 108,870 45,500 NP
100 71,250 45,000 125,620 52,500 NP
4
0-25 42,750 NP 75,370 NP NP
50 46,310 NP 81,650 NP NP
100 53,430 NP 94,210 NP NP
5
0-25 NP NP 60,300 NP NP
50 NP NP 65,320 NP NP
100 NP NP 75,370 NP NP

Table 8 cont. – Group F NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
d. Sprinklered Group F buildings of one or two stories may be unlimited in area if the frontage width is at least
Group F-2 Sprinklered Buildings a, b, c
IIIA IIIB IV VA VB
1
0-25 114,000 72,000 202,000 84,000 52,000
50 121,120 76,500 214,620 89,250 55,250
100 135,370 85,500 239,870 99,750 61,750
100(60’)d
UL UL UL UL UL
2
0-25 85,500 54,000 151,500 63,000 39,000
50 92,620 58,500 164,120 68,250 42,250
100 106,870 67,500 189,370 78,750 48,750
100(60’)d
UL UL UL UL UL
3
0-25 85,500 54,000 151,500 63,000 39,000
50 92,620 58,500 164,120 68,250 42,250
100 106,870 67,500 189,370 78,750 48,750
4
0-25 64,120 40,500 113,620 47,250 NP
50 69,460 43,870 123,090 51,180 NP
100 80,150 50,620 142,030 59,060 NP
5
0-25 51,300 NP 90,900 NP NP
50 55,570 NP 98,470 NP NP
100 64,120 NP 113,620 NP NP
6
0-25 NP NP 75,750 NP NP
50 NP NP 82,060 NP NP
100 NP NP 94,680 NP NP

Group I Sprinklered Buildings
Section 903.2.6 requires all Group I buildings to have automatic sprinkler systems. Therefore,
there are no maximum building heights and areas for nonsprinklered Group I buildings, with a
single exception: Exception 2 of Section 903.2.6 allows Group I-4 day care facilities on the ground
floor (level of exit discharge) to be nonsprinklered when there is an exterior exit door in every
room where care is provided.
Additionally, Section 903.2.6 allows Group I-1 Condition 1 buildings to use NFPA 13R-compli-
ant sprinkler systems. In this case, there is no increase in area for having a sprinkler, rather only
an increase in area for frontage is allowed. NFPA 13R-compliant maximum floor areas are shown
in Table 10.
Table 9 – Group I-4 Nonsprinklered Buildings – Maximum floor area per story
NP = Not Permitted
c. Section 903.2.6 Exception 2 permits Group I-4 day care facilities to be nonsprinklered when the facility is at
the level of exit discharge and has at least one exterior exit door from each room where care is provided.
d. Types VA and VB construction do not permit two stories above grade plane.
e. Maximum floor areas for nonsprinklered buildings above one story apply to existing construction only.
Table 10 – Group I-1 Condition 1, NFPA 13R-Compliant Sprinklered Buildings – Maximum floor area
per story
NP = Not Permitted
a. NFPA 13R-compliant sprinklered buildings do not receive an increase of area for sprinklers. There is an
increase in building area for open frontage, if applicable. The maximum floor area for four stories above
grade plane was determined in accordance with Section 506.2.3, taking Sa = 4 as permitted for buildings
equipped with an NFPA 13R sprinkler system.
d. Section 903.2.6 permits Group I-1 occupancies to be sprinklered with an NFPA 13R-compliant system. The
occupancies do not qualify for area increases due to sprinklers.
Group I-4 Nonsprinklered Buildings a,b,c
IIIA IIIB IV VA VB
1 & 2d
0-25 23,500 13,000 25,500 18,500 9,000
50 29,370 16,250 31,870 23,120 11,250
100 41,120 22,750 44,620 32,370 15,750
3e
0-25 23,500 NP 25,500 NP NP
50 29,370 NP 31,870 NP NP
100 41,120 NP 44,620 NP NP
Group I-1 Condition 1 Sprinklered Buildings - NFPA 13R Compliant a, b, c, d
IIIA IIIB IV VA VB
1, 2 & 3e
0-25 16,500 10,000 18,000 10,500 4,500
50 20,620 12,500 22,500 13,120 5,620
100 28,870 17,500 31,500 18,370 7,870
4
0-25 16,500 NP 18,000 NP NP
50 20,620 NP 22,500 NP NP
100 28,870 NP 31,500 NP NP

Table 11 – Group I NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story
NP = Not Permitted
mum total allowable building area by the number of stories in accordance with Section 506.2.3. The floor
d. Section 903.2.6 permits Group I-1 Condition 1 occupancies to be sprinklered with an NFPA 13R system that
does not qualify for area increases due to sprinklers. See Table 10 for area limits.
Group I-1 Condition 1 Sprinklered Buildings a, b, c, d
IIIA IIIB IV VA VB
1
0-25 66,000 40,000 72,000 42,000 18,000
50 70,120 42,500 76,500 44,620 19,120
100 78,370 47,500 85,500 49,870 21,370
2, 3
0-25 49,500 30,000 54,000 31,500 13,500
50 53,620 32,500 58,500 34,120 14,620
100 61,870 37,500 67,500 39,370 16,870
4
0-25 37,120 22,500 40,500 23,620 NP
50 40,210 24,370 43,870 25,590 NP
100 46,400 28,120 50,620 29,530 NP
5
0-25 29,700 NP 32,400 NP NP
50 32,170 NP 35,100 NP NP
100 37,120 NP 40,500 NP NP
Group I-1 Condition 2 Sprinklered Buildings a, b, c
IIIA IIIB IV VA VB
1
0-25 66,000 40,000 72,000 42,000 18,000
50 70,120 42,500 76,500 44,620 19,120
100 78,370 47,500 85,500 49,870 21,370
2, 3e
0-25 49,500 30,000 54,000 31,500 13,500
50 53,620 32,500 58,500 34,120 14,620
100 61,870 37,500 67,500 39,370 16,870
4
0-25 37,120 NP 40,500 NP NP
50 40,210 NP 43,870 NP NP
100 46,400 NP 50,620 NP NP

Table 11 cont. – Group I NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story
NP = Not Permitted
e. Note that Tables 504.3 and 504.4 do not allow an increase in building height or stories with automatic sprin-
klers in new or existing Group I-1 Condition 1 and Group I-2 buildings; a building area increase is allowed.
Group I-2 Sprinklered Buildings b, c
IIIA IIIB IV VA VB
1
0-25 48,000 NP 48,000 38,000 NP
50 51,000 NP 51,000 40,370 NP
100 57,000 NP 57,000 45,120 NP
2d, e
0-25 NP NP NP NP NP
50 NP NP NP NP NP
100 NP NP NP NP NP
Group I-3 Sprinklered Buildings b, c
IIIA IIIB IV VA VB
1
0-25 42,000 30,000 48,000 30,000 20,000
50 44,620 31,870 51,000 31,870 21,250
100 49,870 35,620 57,000 35,620 23,750
2
0-25 31,500 22,500 36,000 22,500 15,000
50 34,120 24,370 39,000 24,370 16,250
100 39,370 28,120 45,000 28,120 18,750
3
0-25 31,500 NP 36,000 22,500 NP
50 34,120 NP 39,000 24,370 NP
100 39,370 NP 45,000 28,120 NP
Group I-4 Sprinklered Buildings a, b, c
IIIA IIIB IV VA VB
1
0-25 94,000 52,000 102,000 74,000 36,000
50 99,870 55,250 108,370 78,620 38,250
100 111,620 61,750 121,120 87,870 42,750
2
0-25 70,500 39,000 76,500 55,500 27,000
50 76,370 42,250 82,870 60,120 29,250
100 88,120 48,750 95,620 69,370 33,750
3
0-25 70,500 39,000 76,500 NP NP
50 76,370 42,250 82,870 NP NP
100 88,120 48,750 95,620 NP NP
4
0-25 52,870 NP 57,370 NP NP
50 57,280 NP 62,150 NP NP
100 66,090 NP 71,710 NP NP

Table 12 – Group M Nonsprinklered Buildings – Maximum floor area per story a, b, c, d
NP = Not Permitted
d. Sprinklers must be provided for Group M occupancies when the fire area exceeds 12,000 square feet, or the
combined area of all Group M occupancies exceeds 24,000 square feet, in accordance with Section 903.2.7,
or by reason of other specific conditions in that section. In lieu of sprinklers, compartmentalization of the
floor area into fire areas not more than 12,000 square feet per compartment and not more than 24,000 square
feet total can be provided with fire-resistance-rated construction in accordance with Chapter 7.
e. Type VB construction does not permit two stories above grade plane.
IIIA IIIB IV VA VB
1, 2e
0-25 18,500 12,500 20,500 14,000 9,000
50 23,120 15,620 25,620 17,500 11,250
100 32,370 21,870 35,870 24,500 15,750
3
0-25 18,500 NP 20,500 14,000 NP
50 23,120 NP 25,620 17,500 NP
100 32,370 NP 35,870 24,500 NP
4
0-25 13,870 NP 15,370 NP NP
50 17,340 NP 19,210 NP NP
100 24,280 NP 26,900 NP NP

Table 13 – Group M NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story a, b, c
NP = Not Permitted
UL = Unlimited
d. Sprinklered Group M buildings of one or two stories may be unlimited in area if the frontage width is at least
IIIA IIIB IV VA VB
1
0-25 74,000 50,000 82,000 56,000 36,000
50 78,620 53,120 87,120 59,500 38,250
100 87,870 59,370 97,370 66,500 42,750
100 (60’)d
UL UL UL UL UL
2
0-25 55,500 37,500 61,500 42,000 27,000
50 60,120 40,620 66,620 45,500 29,250
100 69,370 46,870 76,870 52,500 33,750
100 (60’)d
UL UL UL UL UL
3
0-25 55,500 37,500 61,500 42,000 NP
50 60,120 40,620 66,620 45,500 NP
100 69,370 46,870 76,870 52,500 NP
4
0-25 41,620 NP 46,120 31,500 NP
50 45,090 NP 49,960 34,120 NP
100 52,030 NP 57,650 39,370 NP
5
0-25 33,300 NP 36,900 NP NP
50 36,070 NP 39,970 NP NP
100 41,620 NP 46,120 NP NP

Group R Sprinklered Buildings
Section 903.2.8 requires all Group R buildings to have automatic sprinkler systems; therefore,
there are no maximum building heights and areas for nonsprinklered Group R buildings. When
using NFPA 13R- or 13D-compliant sprinkler systems, there is no increase in area for having a
sprinkler system, rather only an increase in area for frontage is allowed. NFPA 13D- and NFPA
13R-compliant maximum floor area tables are below.
Use of NFPA 13D-compliant sprinkler systems is allowed for one- and two-family dwellings,
townhouses, and certain congregate living facilities (Group R-3 and Group R-4 Condition 1) in
accordance with Sections 903.2.8 and 903.3.1.3. NFPA 13D-compliant sprinkler systems are also
allowed in single-family dwellings with care facilities for five or fewer individuals receiving care.
Table 14 – Group R-3 and R-4 Condition 1, NFPA 13D-Compliant Sprinklered Buildings – Maximum
floor area per story
NP = Not Permitted
UL = Unlimited
e. NFPA 13D-compliant sprinkler systems are allowed in Group R-3 and Group R-4 Condition 1 residences
only in accordance with Section 903.3.1.3. Group R-4 Condition 2 buildings require NFPA 13R-compliant
sprinkler systems.
Group R-3 Sprinklered Buildings – NFPA 13D Complianta, b, c, e
IIIA IIIB IV VA VB
1, 2 & 3 0-100 UL UL UL UL UL
4 0-100 UL UL UL NP NP
Group R-4 Condition 1 Sprinklered Buildings – NFPA 13D Complianta, b, c, e
IIIA IIIB IV VA VB
1, 2 & 3d
0-25 24,000 16,000 20,500 12,000 7,000
50 30,000 20,000 25,620 15,000 8,750
100 42,000 28,000 35,870 21,000 12,250
4
0-25 18,000 12,000 15,370 NP NP
50 22,500 15,000 19,210 NP NP
100 31,500 21,000 26,900 NP NP

Table 15 – Group R, NFPA 13R-Compliant Sprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
a. NFPA 13R-compliant sprinklered buildings do not receive an increase of area for sprinkler. There is an
increase in building area for open frontage, if applicable.
d. The maximum building height is 60 feet and four stories in accordance with Sections 504 and 903.3.1.2.
e. The maximum floor area for four stories above grade plane was determined in accordance with Section
506.2.3, taking Sa = 4 as permitted for buildings equipped with an NFPA 13R sprinkler system. The floor area
of the four stories is assumed to be equal.
Group R-1, R-2, R-4 Sprinklered Buildings – NFPA 13R Compliant a, b, c
IIIA IIIB IV VA VB
1, 2 & 3d
0-25 24,000 16,000 20,500 12,000 7,000
50 30,000 20,000 25,620 15,000 8,750
100 42,000 28,000 35,870 21,000 12,250
4e
0-25 24,000 16,000 20,500 12,000 NP
50 30,000 20,000 25,620 15,000 NP
100 42,000 28,000 35,870 21,000 NP
Group R-3 Sprinklered Buildings- NFPA 13R Compliant a, b, c
IIIA IIIB IV VA VB
1, 2 & 3
0-25 UL UL UL UL UL
50 UL UL UL UL UL
100 UL UL UL UL UL
4d
0-25 UL UL UL UL UL
50 UL UL UL UL UL
100 UL UL UL UL UL

Table 16 – Group R, NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
a. The maximum floor area for four or more stories above grade plane shown was determined by dividing the
maximum total allowable building area determined in accordance with Section 506.2.3 by the number of sto-
ries. The floor area of the stories is assumed to be equal.
b. Frontage is based on open space widths of 30 feet or more.
d. Group R occupancies must have a NFPA 13 sprinkler system unless specifically allowed an NFPA 13R or
13D sprinkler system in accordance with Section 903.3.1. If NFPA 13R is used, the building must meet
height limits of four stories and 60 feet in accordance with Tables 504.3 and 504.4 and there is no increase in
area per floor for sprinklers. Using NFPA 13D, there is no increase in building height or area due to use of the
automatic sprinkler system in accordance with Tables 504.3 and 504.4, use the rows for nonsprinklered build-
ings to determine maximum building area. See Tables 14 and 15 for area increases due to frontage.
Group R-1, R-2, R-4 Sprinklered Buildings a, b, c, d
IIIA IIIB IV VA VB
1
0-25 96,000 64,000 82,000 48,000 28,000
50 102,000 68,000 87,120 51,000 29,750
100 114,000 76,000 97,370 57,000 33,250
2, 3
0-25 72,000 48,000 61,500 36,000 21,000
50 78,000 52,000 66,620 39,000 22,750
100 90,000 60,000 76,870 45,000 26,250
4
0-25 54,000 36,000 46,120 27,000 NP
50 58,500 39,000 49,960 29,250 NP
100 67,500 45,000 57,650 33,750 NP
5
0-25 43,200 28,800 36,900 NP NP
50 46,800 31,200 39,970 NP NP
100 54,000 36,000 46,120 NP NP
Group R-3 Sprinklered Buildings a, b, c, d
IIIA IIIB IV VA VB
1, 2, 3 & 4
0-25 UL UL UL UL UL
50 UL UL UL UL UL
100 UL UL UL UL UL
5
0-25 UL UL UL NP NP
50 UL UL UL NP NP
100 UL UL UL NP NP

Table 17 – Group S Nonsprinklered Buildings – Maximum floor area per story
NP = Not Permitted
d. Group S-1 occupancies with storage of commercial motor vehicles must have sprinklers when the fire area
exceeds 5,000 square feet in accordance with Section 903.2.10.1. Group S-1 occupancies used to store mat-
tresses or upholstered furniture must be sprinklered when the fire area exceeds 2,500 square feet in accor-
dance with Section 903.2.9. Sprinklers must be provided for Group S-1 occupancies when the fire area
exceeds 12,000 square feet per compartment, or the combined area of all Group S-1 occupancies exceeds
24,000 square feet total, in accordance with Section 903.2.9, or by reason of other specific conditions in that
section. In lieu of sprinklers, compartmentalization of the floor area can be provided with fire-resistance-
rated construction in accordance with Chapter 7.
e. Repair garages in Group S-1 occupancies with more than one story, including basements, must have sprin-
klers when a fire area exceeds 10,000 square feet in accordance with Section 903.2.9.1.
f. Group S-1 occupancies storing tires must be sprinklered when the fire area exceeds 20,000 cubic feet in
accordance with Section 903.2.9.2.
g. Type VB construction does not permit two stories above grade plane.
Group S-1 Nonsprinklered Buildings a, b, c, d, e, f
IIIA IIIB IV VA VB
1, 2g
0-25 26,000 17,500 25,500 14,000 9,000
50 32,500 21,870 31,870 17,500 11,250
100 45,500 30,620 44,620 24,500 15,750
3
0-25 26,000 NP 25,500 14,000 NP
50 32,500 NP 31,870 17,500 NP
100 45,500 NP 44,620 24,500 NP
4
0-25 NP NP 19,120 NP NP
50 NP NP 23,900 NP NP
100 NP NP 33,460 NP NP

Table 17 cont. – Group S Nonsprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
d. Group S-2 occupancies with enclosed parking garages must have sprinklers when the fire area exceeds
12,000 square feet per compartment, in accordance with Section 903.2.10, or by reason of other specific con-
ditions in that section. Buildings with parking garages for commercial motor vehicles must be sprinklered
when the fire area exceeds 5,000 square feet.
f. Single-story Group S-2 occupancies may be unlimited in area if the frontage width is at least 60 feet in accor-
Group S-2 Nonsprinklered Buildingsa, b, c, d
IIIA IIIB IV VA VB
1
0-25 39,000 26,000 38,500 21,000 13,500
50 48,750 32,500 48,120 26,250 16,870
100 68,250 45,500 67,370 36,750 23,620
100 (60’)f
UL UL UL UL UL
2 & 3e
0-25 39,000 26,000 38,500 21,000 13,500
50 48,750 32,500 48,120 26,250 16,870
100 68,250 45,500 67,370 36,750 23,620
4
0-25 29,250 NP 28,870 15,750 NP
50 36,560 NP 36,090 19,680 NP
100 51,180 NP 50,530 27,560 NP
5
0-25 NP NP 23,100 NP NP
50 NP NP 28,870 NP NP
100 NP NP 40,420 NP NP

Table 18 – Group S NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
d. Sprinklered Group S buildings of one or two stories may be unlimited in area if the frontage width is at least
Group S-1 Sprinklered Buildingsa, b, c
IIIA IIIB IV VA VB
1
0-25 104,000 70,000 102,000 56,000 36,000
50 110,500 74,370 108,370 59,500 38,250
100 123,500 83,120 121,120 66,500 42,750
100(60’)d
UL UL UL UL UL
2
0-25 78,000 52,500 76,500 42,000 27,000
50 84,500 56,870 82,870 45,500 29,250
100 97,500 65,620 95,620 52,500 33,750
100(60’)d
UL UL UL UL UL
3
0-25 78,000 52,500 76,500 42,000 NP
50 84,500 56,870 82,870 45,500 NP
100 97,500 65,620 95,620 52,500 NP
4
0-25 58,500 NP 57,370 31,500 NP
50 63,370 NP 62,150 34,120 NP
100 73,120 NP 71,710 39,370 NP
5
0-25 NP NP 45,900 NP NP
50 NP NP 49,720 NP NP
100 NP NP 57,370 NP NP

Table 18 cont. – Group S NFPA 13-Compliant Sprinklered Buildings – Maximum floor area per story
NP = Not Permitted
UL = Unlimited
The floor area of each of the stories is assumed to be equal.
d. Sprinklered Group S buildings of one or two stories may be unlimited in area if the frontage width is at least
Group S-2 Sprinklered Buildings a, b, c
IIIA IIIB IV VA VB
1
0-25 156,000 104,000 154,000 84,000 54,000
50 165,750 110,500 163,620 89,250 57,370
100 185,250 123,500 182,870 99,750 64,120
100(60’)d
UL UL UL UL UL
2
0-25 117,000 78,000 115,500 63,000 40,500
50 126,750 84,500 125,120 68,250 43,870
100 146,250 97,500 144,370 78,750 50,620
100(60’)d
UL UL UL UL UL
3
0-25 117,000 78,000 115,500 63,000 40,500
50 126,750 84,500 125,120 68,250 43,870
100 146,250 97,500 144,370 78,750 50,620
4
0-25 87,750 58,500 86,620 47,250 NP
50 95,060 63,370 93,840 51,180 NP
100 109,680 73,120 108,280 59,060 NP
5
0-25 70,200 NP 69,300 37,800 NP
50 76,050 NP 75,070 40,950 NP
100 87,750 NP 86,620 47,250 NP
6
0-25 NP NP 57,750 NP NP
50 NP NP 62,560 NP NP
100 NP NP 72,180 NP NP

Cover Photo Credit (photos on right):
One North, East Building,
Holst Architecture, Froelich Engineers,
photo Josh Partee
American Wood Council
info@awc.org
www.awc.org
International Code Council
eCodes@iccsafe.org
www.iccsafe.org

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