Fire Resistance Design for WoodFire-Resistance Design for Wood Construction - BCD 220-1James B. Smith, P.E.Midwest Regional ManagerAmerican Wood Council

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DescriptionDetermining the proper code application for wood-framefi bli b h ll i d i ft f thfire assemblies can be challenging and is often furthercomplicated with increases in a project’s size and scale.In a building environment where the ability to maximizeheight and area is key to cost effectiveness, designersmust understand the gamut of fire protectiong pconsiderations applicable to mid- and low-rise woodstructures. This presentation will include coderequirements, compliance options and nuances relatedto assembly selection for required fire-resistance-ratedfloor/ceiling assemblies exterior walls fire barriers firefloor/ceiling assemblies, exterior walls, fire barriers, firepartitions, and fire walls. Topics will include distinctionsbetween fire-resistive elements for separation vs. classof construction. 3

Learning Objectives

1. Apply code requirements and intent for wood-f fi i d bliframe fire-resistance rated assemblies.

2. Discuss the differences in exterior walls, fire walls, fire barriers, and fire partitions considering performance expectations, code requirements and appropriate applicationrequirements, and appropriate application.

3. Understand the paths to achieving code-compliant, fire-resistance rated wood-frame assemblies as outlined by the 2015 IBC.

4. Recognize important nuances in the various methods for demonstrating fire-resistance including: tested assemblies, prescriptive designs, calculations, and engineering analysis. 4

Outline

• Code Overview• Code Overview• Background• Fire-resistance

building elementsbuilding elements• Achieving Fire-

Resistance

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International Building Code

The IBC• Controls building size• Regulates types of

materialsmaterials• Stipulates fire-

resistance

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International Building Code

Allowable heights & areas determined by

• Tabular values• Factors allowing• Factors allowing

increases• Frontage• Sprinkler Systems

Special Provisions IBC• Special Provisions IBC 510

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Allowable Heights & AreasAllowable area is based uponupon

• Use of building• Type of construction• Frontage• Existence of sprinkler

systemsTabular areas establishminimum allowable building areas that can be increased byareas that can be increased by added fire safety features -frontage and/or frontage.

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Allowable Heights & Areas

Each occupancy groupEach occupancy group presents a different level of fire and life safety risk:

N b f t• Number of occupants• Capability of occupants• Fuel load

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Allowable Heights & AreasAllowable heights and areas are based on a concept of equivalent risk, involving three p q , ginterdependent considerations

• level of fire hazard likely to be associated with the occupancy

• nature of contents associated with the use• nature of contents associated with the use• level of overall fire protection provided by the

• Type of construction• Setbacks of the building from other structures

(exposure)• Sprinklers and life safety systems• Other code trade-offs 10

Table 601 Fire-Resistance Rating Requirements For Building Elements (hours)

Building Elements

Building Elements (hours)

BUILDING ELEMENTTYPE I TYPE II TYPE III

TYPE

IVTYPE V

A B Ad B Ad B HT Ad B

Primary structural frameg

( )(see Section 202)

3a 2a 1 0 1 0 HT 1 0

Bearing walls, Exteriorf, g

Interior 3

3a2

2a1

1

0

0

2

1

2

0

2

1/HT

1

1

0

0

11

Nonbearing walls and

partitions, ExteriorSee Table 602

Nonbearing walls and

partitions, Interiore

0 0 0 0 0 0See

Section 0 0

Exterior Walls

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• Define separate buildings for allowable building size (706)

Fire Walls (706)

size (706)• Not fire barriers (707)• Not fire partitions (708)• Not smoke barriers, smoke partitions or horizontal

assembliesassemblies• Table 706.4 gives required ratings based on occupancy

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• Type V construction

Fire Walls (706.3)

• Fire walls may be wood frame

• Types I, II, III and IV construction• Fire walls must be of noncombustible materials

in accordance with Section 706.3

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• A fire-resistance-rated wall assembly of materials

Fire Barrier (707)

designed to restrict the spread of fire in which continuity is maintained

• Of materials permitted by the building type of construction

• Fire-resistance rating 707.3 - specific ratings as indicated for shaft enclosures, interior exit stairways and ramp, enclosed exit access stairways, exit passageway, horizontal exit, atriums, incidental uses, control areas, separated occupancies fire areasseparated occupancies, fire areas

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Fire-resistance rating for separation of fire

Fire Barrier (707)

areas per table 707.3.10

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Separation of Occupancies

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• A vertical assembly of materials designed to restrict the spread of fire in which openings are

Fire Partition (708)

restrict the spread of fire in which openings are protected.

• Wall assemblies for:• Separation walls for Group I-1, R-1, R-2 and R-3 per section

420 2420.2• Walls separating tenant spaces in covered and open mall

buildings per section 402.4.2.1• Corridor walls per section 1020.1

El t l bb ti ti 3006 2• Elevator lobby separation per section 3006.2• Egress balconies per section 1019.2

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• A vertical assembly of materials designed to restrict the spread of fire in which openings are

Fire Partition (708)

restrict the spread of fire in which openings are protected. cont.

• Of materials permitted by the building type of construction

• Fire-resistance rating 708.3 not less than 1 hour.

• See exceptions for corridor walls, dwelling unit separations, and sleeping unit separations

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• A continuous membrane, either vertical or

Smoke Barriers (709)

horizontal, such as a wall, floor or ceiling assembly, that is designed and constructed to restrict the movement of smoke.

• Vertical and horizontal smoke barrierse t ca a d o o ta s o e ba e s• Of materials permitted by the building type of

construction• 1 hour fire-resistance rating Exception: Smoke barriers

constructed of minimum 0.10- inch-thick (2.5 mm) steel in b ld ( )Group I-3 buildings. (709.3)

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• A fire-resistance-rated floor or roof assembly of

Horizontal Assemblies (711)

materials designed to restrict the spread of fire in which continuity is maintained.

• Of materials permitted by the building type of construction

• Fire-resistance rating - specific ratings as indicated 711.2.4 but not less than that for building type of construction : separating mixed occupancies, fire areas, dwelling units and sleeping units,

k t t i id t l th tismoke compartments, incidental uses, other separations.

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Outline

• Code Overview• Code Overview• Background• Fire-resistance

building elementsbuilding elements• Achieving Fire-

Resistance

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1 Tested fire assembly (ASTM E 119 or UL 263)

Methods for Determining Fire-Resistance (703)

1. Tested fire assembly (ASTM E 119 or UL 263)2. Fire-resistance designs documented in approved

sources 3. Prescriptive assemblies using of fire-resistance-rated

designs in Section 721designs in Section 7214. Calculation of fire-resistance per Section 7225. Engineering analysis based on a comparison of

building element, component or assembly designs that have been tested

6. Alternative protection methods per Section 104.117. Fire-resistance designs certified by an approved

agency23

Fire TestsTested fire assembly (ASTM E 119)

http://www.awc.org/Code-Officials/2012-IBC-Challenges/# 24

Fire TestAmerican Wood CouncilASTM E119 Fire Endurance Half-lapped –Test• 5-Ply CLT (approx. 7” thick)• 5/8” Type X GWB each side• Sought 2 hour rating• RESULTS: 3 hours 6 minutes

ppmiddle of panel

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• Based on testing to the ASTM E 119 or UL 263 d d

Documented in Approved Source

standard• Choose listed assemblies from fire-resistance

publications or directories

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Documented in Approved SourceFire-resistance designs - AWC Design for Code Acceptance Pubs -Acceptance Pubs

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Documented in Approved Source

DCA 3DCA 3Fire-Resistive Wood Wall and Floor/Ceiling Assemblies• ASTM E 119 or UL 263• NFPA 251

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Documented in Approved Source

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Documented in Approved Source

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Documented in Approved Source

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Fire-resistance of certain wood assemblies is prescribed in Section 721 based on testing using ASTM E 119 or UL 263

Prescriptive Fire-Resistance Rated Assemblies

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Prescriptive Fire-Resistance-Rated Assemblies

Fire-resistance of certain wood assemblies is ib d i S ti 721 b d t ti iprescribed in Section 721 based on testing using

ASTM E 119 or UL 263

• Fire-resistance of wood frame assemblies

Calculated Resistance (703.3)

also may be calculated based on the known fire-resistance of the components, using the provisions of Section 722.6

• 1.0 hour maximum0 ou a u

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Calculated Fire Resistance (722.6)

DCA 4DCA 4 Component Additive Method (CAM) for Calculating and Demonstrating AssemblyDemonstrating Assembly Fire Endurance

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CAM

Calculated Fire Resistance (722.6)

Membrane Table

Time AssignedTime Assigned to Protective Membranes

•IBC Table 722 6 2(1)722.6.2(1)

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CAM Wood Component Table

Calculated Fire Resistance (722.6)

CAM Wood Component TableAssigned Times for Wood ComponentsIBC Table 722.6.2(2)

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CAM Wall Membranes

Calculated Fire Resistance (722.6)

Membranes on Exterior Face of WallsIBC Table 722.6.2(3)

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CAM Cavity Insulation Table

Calculated Fire Resistance (722.6)

yAssigned Times for Insulation of Cavity

•IBC Table 722.6.2(5)

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Interior Wall

CAM Example 1

Interior Wall

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Floor/Ceiling with Wood Joists

CAM Example 2

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Floor/Ceiling with I-joists

CAM Example 3

/ g j

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Columns within Wall Assembly

IBC 704.2 and 704.3 No addition

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al fireproofing required for the co

lumnin the assembly

• 704.2 Column protection (IBC 2018 text)

Columns within Wall Assembly

• “Exception: Columns that meet the limitations of Section 704.4.1”

• 704.4.1 Light-frame construction (IBC 2018 text)• “Studs columns and boundary elements that• Studs, columns, and boundary elements that

are integral elements in walls of light-frame construction, and are located entirely between the top and bottom plates or tracks shall be permitted to have required fire-resistance ratings provided by the membrane protection provided for the wall.”

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Structural Stability 705.6

2 hour wall

1 hour floor

2 hour wall

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Calculated Fire-Resistance

Fire-resistance up to two hours

• Columns

• Beams

• Tension Members…

e s o e be s

• ASD only

Products

• Lumber

Gl l

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• Glulam

• SCL

• Decking

• CLT

Fire Design of Exposed Wood Members

Beam Fire Test ASTM E 119

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Calculated Fire-Resistance (722)

Chapter 16 of the National Design Specification® (NDS®)

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Effective char rate

Fire Design of Exposed Wood Members

lid l l d l i d f d l i dsolid sawn, structural glued laminated softwood, laminated veneer lumber, parallel strand lumber, and laminated strand lumber

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Effective char depth

Fire Design of Exposed Wood Members

C16.2.1.2 Using Equation 16.2-1 and assuming nominal char rate, n or 1.5 inches/hr:

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Fire Design of Exposed Wood Members

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CLT manufactured with laminations of equal thickness

Fire Design of Exposed Wood Members

CLT manufactured with laminations of equal thickness

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Technical Report No. 10 (TR10)

Calculated Resistance (722)

(TR10)• contains background and

examples for the method

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TR-10 Design Example

TR10 containsTR10 contains:• decking• beam

l• column• CLT• etc

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Fire-Resistance of Exposed Wood

16 3 Wood Connections16.3 Wood Connections• Where fire endurance is required,

connectors and fasteners shall be protected from fire exposure

• Wood• Fire-rated gypsum board

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Connections

Beam-to-column(Protection provide(Protection provided by membrane)

Source: AWC TR-10 56

Connections

Concealed

Source: AWC TR-10

Concealedbeam-to-column

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Connections

Source: AWC TR-10

Beam supporting one hour rated ceiling58

Connections

Covered column connection

Source: AWC TR-10 59

Connections

Concealed beam-to-

girder connection

Source: AWC TR-10 60

Fire Design of Exposed Wood Members

722.6.3 deleted

Limited to 1-Hour – IBC 722.6.1.1Si lifi d h

722.6.3 deleted NOT INCLUDED IN 2015 IBC

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Simplified approachOnly Beams/Columns

Fire Design of Exposed Wood Members

DCA 2Design of Fire-Resistive Exposed Wood Members• Glued-laminated

timber, sawn lumber, & timber decking

• 1 1 5 & 2 hours• 1, 1.5 & 2 hours

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May be used in almost all occupancies.

Wood Interior Finish (Chapter 8)

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Wood Interior Finish Classification System

Nonsprinklered Buildings: Minimum Interior FinishNonsprinklered Buildings: Minimum Interior Finish Classification by Occupancy

Location Minimum Interior Finish Classification

Ab B CAb B C

Exit enclosures and exit

passagewaysc

A, B, E, I, M, R-1, R-4

F, S, R-2 R-3

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Corridors Ad, I-2, I-3,

I-4

B, E, M, S,I-1, R-1, R-2, R-4

F, R-3

(Table 803.11)

Wood Interior Finish Classification System

Sprinklered Buildings: Minimum Interior FinishSprinklered Buildings: Minimum Interior Finish Classification by Occupancya, b

Location Minimum Interior Finish Classification

A B CA 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

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Corridors I-3 A, I-2, I-4B, E, F, M,R, S, I-1

A

(Table 803.11)

Wood Interior Finish (803)• Most wood species

lif Cl Cqualify as Class C or Class B.

• Wood boards and panels may meet Class A criteria whenA criteria when pressure treated with a fire-retardant chemical.

• AWC’s DCA-1

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• AWC s DCA-1 documents the performance.

Flame Spread

Class I or A 0 ‐ 25

Class II or B 26 ‐ 75

fire retardant treated wood

redwoodcedard l f

pine (other than lodge pole, ponderosa & red)

most other wood speciessoftwood plywood

Class III or C 76 ‐ 200

douglas‐firhem‐fir

spruce

softwood plywoodhardwood plywoodparticleboard

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Flame Spread

E84 T l• E84 Tunnel Apparatus

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Smoke Developed Index

A smoke-developed pindex was also measured for some of the wood products listed in DCA 1. None of the products testedof the products tested exceeded the limiting value of 450 commonly used in building code regulationsregulations.

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Wood Interior Finish – Exceptions

• Traditional wood floor covering is exempt from interior floor finish requirements (804.1).

• Exposed portions of Type IV structural members also

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members also exempt (803.3).

Design for Code Acceptance Pubs.

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Available for free download www.awc.org

• Special occupancies

2015 Code Conforming Wood Design

• Fire-resistance• Building features• Wood in noncombustible

construction types• Structural considerations• Precautions during

construction• Also available for 2009 and

2012 IBC2012 IBC• http://awc.org/codes-

standards/buildingcodes/ccwd 72

• This concludes The American Institute of Architects Continuing Education Systems Course

Questions?

Education Systems Course

American Wood Councilinfo@awc.orgwww.awc.org

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Questions

J B S i h P EJames B. Smith, P.E.Midwest Regional Manager

jsmith@awc.org608-635-6635608 635 6635