Fire Requirements For Foam Plastic Insulation and WRBs in

Exterior WallsPresented to

ByJesse J. Beitel

July 31, 2012

Learning Objectives

Code requirements for foam plastic in exterior walls

History of NFPA 285 Fire test Other Fire tests required Code requirements for Water-Resistive

Barriers Applicability and Use of NFPA 285

3

Continuous Insulation (CI)Concept

ASHRE 90.1 – Commercial IECC (Energy Code) – Commercial &

Residential Concept – Wrap building w/ insulation

outboard of studs Helps with thermal conduction, dew point,

etc. Creates high R-value walls

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Insulation In Exterior Walls Location in walls – CI / Cavity / Both Can use noncombustible or combustible non-foam plastic

insulation Fiberglass, Mineral wool Cellulose, others Minimal fire requirements

Can use combustible foam plastic insulation Many types – XPS, EPS, Polyiso, SPF, etc. Characteristics different Regulated the same Fire requirements for walls and foam plastics vary based on Type

of Construction, etc.

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Fire Requirements Vary

One & Two Family Dwellings – Exterior walls - IRC regulates

Type V – Exterior walls - combustible – IBC regulates

Types I, II, III, IV – Exterior walls to be noncombustible unless allowed – IBC regulates

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IRC (2012) Fire Requirements

Non-foam plastic insulation Noncombustible or if combustible then FSI ≤25 &

SDI ≤450 Foam plastic insulation

Labeled FSI ≤75 & SDI ≤450 Protected by 15-minute Thermal Barrier Gable ends in attics – Protect with ignition barrier

Fire Resistance of exterior walls

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IBC (2012) – Type V Fire Requirements

Non-foam plastic insulation Noncombustible or if combustible then FSI ≤25 &

SDI ≤450 Foam plastic insulation (Chapter 26)

Labeled FSI ≤75 & SDI ≤450 Protected by 15-minute Thermal Barrier Gable ends in attics – Protect with ignition barrier

Fire Resistance of exterior walls

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IBC (2012) - Fire Requirements For Type I, II, III or IV – Part 1

Noncombustible Insulation - OK Fiberglass Mineral wool

Non-foam plastic combustible insulation Cellulose Insulation, etc. FSI ≤25 & SDI ≤450

Fire Resistance of exterior walls

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IBC - Fire Requirements For Type I, II, III or IV – Part 2

Foam Plastic Insulation Regulated by §2603.5 Applies to exterior walls of Type I – IV

construction Applies to buildings of any height Exceptions:

• Type V buildings• Cold Storage – 1 story & meets other reqm’ts

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IBC - Fire Requirements For Type I, II, III or IV – Foam Plastic

Meet the requirements of NFPA 285 For each combustible component - FSI ≤25 &

SDI ≤450 (ASTM E84) Maintain fire resistance rating (ASTM E119) Foam separated from interior of building by a

Thermal Barrier Gable ends in attics – Protect with ignition barrier

Limits on amount of foam (btu/ft2) (mJ/m2) No ignition when tested via NFPA 268

(Radiant heat exposure test)

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History - Fire Test/Code Development

In mid 1970’s – use of foam plastic on or in noncombustible exterior walls was proposed. EIFS & Steel/Foam/Steel Panels

Problems with use: Exterior walls of Type I, II, III or IV Construction

must be noncombustible construction. Foam plastic is combustible Issues raised over potential for vertical and

horizontal fire spread due to the combustible foam plastic insulation

History (continued)

SPI began work in Codes and testing. Discussions w/ Code & Fire Officials. Drafting of Code language. Testing program

Testing was to determine efficacy of proposed wall systems to resist flame spread.

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Multi-Story Fire Test

Can the wall covering, insulation & assembly resist: Flame propagation over face of the wall covering Vertical flame propagation within the combustible

core or components Flame propagation over interior surface from one

floor to the next Lateral Flame propagation to adjacent

compartments Does not address floor-line joint per se.

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UBC 17-6 /UBC 26-4Test InProgress

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Fire Test/Code Development

Test program completed in late 1980 Code change to Plastics Section adopted in

1988 UBC Versions adopted by NBC and SBC Full-scale test was also adopted as UBC 17-6.

Used by all ESs. In 1994 edition of UBC – reorganization moved

plastics to Chapter 26 and test method became UBC 26-4.

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Fire Test/Code Development (Cont’d)

In early 1990’s a “reduced-scale” fire test was developed.

New test adopted as UBC 26-9 in 1997 edition. Test submitted to NFPA Committee on Fire Tests and

it was adopted as NFPA 285 in 1998. NFPA 285 “Standard Fire Test Method for Evaluation

of Fire Propagation Characteristics of Exterior Non-load-bearing Wall Assemblies Containing Combustible Components”

ICC IBC specifies NFPA 285 Code requirements basically the same since 1988

UBC

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NFPA 285 Test In Progress

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IBC - Fire Requirements For Type I, II, III or IV – Foam Plastic

Meet the requirements of NFPA 285 For each combustible component - FSI ≤25 &

SDI ≤450 (ASTM E84) Maintain fire resistance rating (ASTM E119) Foam separated from interior of building by a

Thermal Barrier Gable ends in attics – Protect with ignition barrier

Limits on amount of foam (Btu/ft2) (MJ/m2) No ignition when tested via NFPA 268

(Radiant heat exposure test)

19ASTM E84 Test Apparatus

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ASTM E119Wall after fire test

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Thermal Barrier Requirement Code requires that foam plastic must be

separated from the interior of the building by a 15-minute thermal barrier.

Applies to any foam plastic application. Thermal barrier is typically 0.5 in. (12.7 mm)

thick gypsum wallboard or meets NFPA 275. Thermal barrier retards heat transmission to

the foam and delays its ignition.

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Ignition Barrier Requirement

Applies to foam plastic insulation in attics & crawl spaces

Only where entrance is made to service utilities

Prescriptive ignition barriers provided in Code: wood, mineral fiber, gypsum wallboard or steel

Not a thermal barrier Alternative assemblies by special testing

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NFPA 259Potential Heat Test

Code requires that the “potential heat” (calculated on areal basis) of the foam plastic not exceed that which is tested via NFPA 285

Uses NFPA 259 – Measures amount of heat released when burned in pure O2

Data from test expressed in Btu/lb (MJ/kg) Convert this to Btu/ft2 (MJ/m2) using thickness and

density of foam plastic. Allows calculation for different densities/thickness

combinations

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NFPA 268 Test

WRB Definitions

My definition = Weather-resistive barriers include: Air barriers Vapor barriers Water barriers ???? Barriers

IBC: Water-resistive barrier

WRB Code Requirement2012 IBC

1403.5 Vertical and lateral flamepropagation. Exterior walls on buildings ofType I, II, III or IV construction that aregreater than 40 feet (12 192 mm) in height above grade plane and contain combustiblewater-resistive barrier shall be tested inaccordance with and comply with theacceptance criteria of NFPA 285.

Exterior veneer

Cavi

ty a

ir sp

ace

Interior wall membrane

Steel stud

Sheathing

Foam insulation

WRB

Insulation instud cavity

Potential Variations of Wall Systems

How Do WRBs Meet NFPA 285?

There is no one test or test assembly to qualify a WRB for use in all assemblies

Perform NFPA 285 test – WRB is one of several materials in assembly

Limited engineering analysis based on NFPA 285 tests in conjunction w/ small-scale tests.

Engineering Analysis

Use WRB X in a successful NFPA 285 test Develop fire performance parameters for

WRB X (ASTM E1354 Cone Calorimeter) Develop fire performance parameters for

WRB Y Compare fire performance parameters – if

same or better, then maybe substitute Y for X in tested assembly

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Applicability of NFPA 285

285 is a test of a complete wall assembly 285 test results apply only to the tested

construction – similar to ASTM E119 Substitutions of one material for another

can cause different test results Addition of combustibles (insulation,

WRBs, etc.) can cause different test results

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Applicability of NFPA 285 (Continued)

Changes in configurations (air gaps, attachment systems, etc.) can cause different results

Wall systems made of a number of previously NFPA 285 tested materials does not ensure a successful NFPA 285 test

Tests are required for many various veneers and other combustible wall components – insulation, WRBs

Applicability of NFPA 285 WRBs

Use of WRBs can cause different results

Substitution of WRBs can cause different results

Even tested WRBs cannot necessarily be applied to other foams, veneers, etc.

Same issues as with other NFPA 285 tests – materials, configuration., etc.

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Summary

Insulation in exterior walls is regulated. Amount of regulation / tests for exterior

insulation and/or insulated exterior walls depends on: Code Type of Construction Type of insulation WRBs

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Summary - Continued

NFPA 285 provides a determination of vertical fire performance of exterior wall assemblies.

NFPA 285 tested systems reduce the potential for vertical flame spread by exterior walls.

NFPA 285 data/results must be used in an appropriate manner.

Thank Youand

Questions?

Jesse J. BeitelSenior Scientist/PrincipalHughes Associates, Inc.

410/737-8677jbeitel@haifire.com