(; Timber P~~~I~~~ ~?~P.~~X P.O. Box 269

305 South 4th Street Springfield, OR 97477-0055

(541) 747-4577 (800) 547-9520

Fax: (541) 744-4237

October 1, 2011

Subject: Flame Spread of Hardwood Plywood

The American Forest & Paper Association, Inc. has conducted numerous tests on a variety of wood products, all in accordance with test method ASTM E-84. The findings from these tests are published in the Design for Code Acceptance, "Flame Spread Performance of Wood Products. "

The rnost commonly accepted flame spread rating system in use today is set forth by the National Fire Protection Association, Life Safety Code, NFPA 101. The NFPA classifies flame spread in the following manner:

Class A 0 to 25 Flame Spread 0 to 450 Smoke Developed Class B 26 to 75 Flame Spread 0 to 450 Smoke Developed Class C 76 to 200 Flame Spread 0 to 450 Smoke Developed

These ratings for both Flame Spread and Smoke Developed are based on arbitrary values of 0 for asbestos cement board and 100 for solid red oak flooring .

The above referenced Design for Code Acceptance thus concludes, "as can be seen from these examples, most tested wood products have a flame spread index less than 200, making them acceptable under current building codes for a wide range of interior finish uses." As the published values also show, no panel product tested exceeded a flame spread value of 200, which falls within the range for Class C as outlined above.

To view the entire AF & PA document, use this link: http://www.awe.org/Publieations/dca1/DCA 1.pdf

Contact your Timber Products Company Sales Representative if you need information for a specific product.

Flame Spread Performance of Wood Products

Wood and wood-based products are widely used in interior wall, ceiling, and floor surfaces in all types of build ings.

Appearance, acoustical qualities, and interior de­sign versatility have made wood surfaces highly de­sired by architects, designers, and building occupants. This publication briefly describes building code flame spread regulations on products used in interior finish and presents performance data on a range of wood products.

Flame Spread Requirements

Most code requirements for wood interior fini sh materials are expressed in terms of flame spread index numbers. These values are determined in a standard fire test which evaluates the surface burning character­istics of a material. Different maximum flame spread indices are permitted depending upon building occu­pancy, location of the material in the building, and the presence of sprinklers. Flame spread indices in this publication are provided for wood materials that qual­ify for various building design requirements.

Test Method

The standard fire test used to evaluate flame spread characteristics of wood building materials in the United States is ASTM E-84, Standard Test Method f or Swjace Burning Characteristics of Build­ing Materials.

The test procedure exposes candidate materials in a horizontal, rectangular tunnel 17 3/4" wide by 12" in height and 25' long. The tunnel is equipped with two gas burners at one end that direct a flame onto the sur­face of the test material under a controlled air flow . Flame spreads al ong the surface of the material as the test progresses. Distance of the flame travel and the rate at which the flame front advances during a 10

Copyright © 2010 American Wood Council

2 FLAME SPREAD PERFORMANCE OF WOOD PRODUCTS

minute exposure determine the calculated flame spread index.

To provide standard conditions for each test, the tunnel is calibrated to an index of 0 for noncombusti­ble materials and 100 for 23/32" red oak flooring. In­dices for tested materials can range from 0 to over 1000.

Classification in Codes are:

Class Flame Spread Range Example Locations

lor A 0-25 Enclosed vertical exits

1I or B 26-75 Exi l access corridors

III or C 76-200 Other rooms and areas

Wood Products

Lumber, plywood, and other wood-based materials exhibit a relatively narrow range of flame spread. Dif­ferences result from factors such as density, thickness, surface characteristics, and chemical constituents. If the material is homogeneous, flame spread may be considered nearly independent of material thickness at th i cknesses greater than 114".

Flame spread indices for a number of species of lumber, plywood, particleboard, shakes, and shingles are listed in Table L In products such as softwood and hardwood plywood, the arrangement and type of com­ponents may also infl uence surface flame spread . Some such products are described by face species and core composition in Table I.. All ratings are based on the ASTM E-84 test method.

Flame spread indices for a number of commer­cially available wood products with factory applied

overlay fi nishes are listed in Table 2. Factory finished wall panels are ty pically tested and labeled to identify the flame spread classifi cation of the finished product. Fin ish composition, adhesive, and finish thickness may, however. affect fl ame spread.

As can be seen from the listed indices, most tested wood products have a flam e spread index less than 200, making them acceptable under current building codes for a wide range of interior finish uses . Flame spread indices for a range of proprietary wood-based interior finish materials are also available from their manufacturers. Commercially available fire retardant treatments fo r wood and panel products can reduce flam e spread performance to an index of 25 or less. Check with the manufacturer for flame spread index.

A smoke-developed index was also measured for some of the wood products listed in Table I and Table 2. This index also has a value of 100 for red oak. None of the products tested exceeded 450, a limiting value common ly used in building code regulations.

While effort has been made to ensure the accuracy of the information in this publication , the American Wood Council, and the Companies and Associations identified , do not assume re­sponsibility for the accuracy of the indices reported , the app licability or extension of the re­ported flame spread values to specific products, or their acceptance for use in particular appli­cations. Includes updates through June 2008.

American Wood Council

FLAME SPREAD PERFORMANCE OF WOOD PRODUCTS

Table 1 Reported Flame Spread Indices

Material

, Wal nut 3/4"

;ii.Ii'~

Copyright © 1997, ) 998,200 1, 2002, 2008, 20 I0 American Wood Council

HARDWOOD PLYWOOD'

PARTICLEBOARD

NOTE: Table 1 footnotes on next page,

American Wood Council

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4 FLAME SPREAD PERFORMANCE OF WOOD PRODUCTS

Table 1 Footnotes Thickness of material tested is one-inch nominal except where Indicated.

2 The ASTM E-84 test method has been revised a number or times during the years referenced by the source reports. However, the E-84 test apparatus has changed little over this period. Slightly different tlame spread indices, usua ll y lower, result wilen rccent E-84 llame spread calc ul ation techniques are appl ied to older wood product data. These changes in tlame spread ind ices are not suffi cient to change the llame spread class for the wood products described in this re­port.

Sources:

APA - APA-The Engineered Wood Association, Research Reports 128, Revised, August 1979.

APA2 - APA-The Engineered Wood Assoc iat ion Test Results.

CWC - Fire Safety Des ign in Bui ldings, Canad ian Wood Council , 1996.

HPV A - Hardwood Pl ywood and Veneer ASSociation, Test Reports , 202 , 203 , 335, 336, 337, 592, and 596; Special tlame spread performance tests, Aug. 1974; T9234, T9237, T9317, T9344, T9354 , May 1995; T9422, T9430, T943 I , T945 3, T9665 , Feb/J uly 1997.

HPVA2 - Hardwood Plywood and Veneer Assoc iation , March/Apfll 1995 , October/December 2000; June 2008.

NIST - National Institute of Standards and Technology (formerly National Bureau of Standards), Technical Notes 879 and 945.

UL - Underwriter's Laboratory, UL 527, May 197 1, Subject 723, Assignm ent 71 SC509, Mar 15 & 16,1971, Assignment 84NK 1898, Fil e R I 09 17, Mar 9, 1984.

WEY - Weyerhaueser Fire Laboratory, 1973, 1987, January & February 1988.

4 Average of 18 tests was 154 with three va lues over 200.

5 The Hem-Fir Species Group represents SIX spec ies Californian Red Fir, Grand Fir, Nobel Fir, PaciJic Sil ve r Fir, Western Hemlock , and White Fir. The re­ported name spread index represents a product containing a mi xture of these species When lumber is from a s ingle species refer to the spec ific spec ies tl ame spread index.

6 Ex posure I or ex terior. A verage of 22 tests was 128.

7 Flame spread of plywood is affected by the spec ies of the face ve neer but can al so be innuenced by the species of the underlying core venee r. Various panel constructions in volving certain core spec ies show a relati ve ly high degree of variability and potential to yield flame spread va lues above 200. Panel construc ­tions in volving cores of aspen, sumauma, ye ll ow poplar and white tlr have exhibited thi s be havio r with average tlame spread indices ranging from 78 to 259. Other factors, in addition to spec ies, including material and process variabl es related to speC ifiC manufacturers can also affect !l ame spread. Thus, for plywood panels with certain core species, test data from the actua lillanufacturer is paI1icul arl y Imporlantln es tablishing the tlame spread class iticati on of the product.

Copyright © 1997, 1998,200 1,2002, 2007, 2008,20 I 0 Amer ican Wood Council

American Wood Council

FLAME SPREAD PERFORMANCE OF WOOD PRODUCTS

Table 2 Reported Flame Spread Indices of Factory Finished Products

Table 2 Footnotes I Source: Hardwood Plywood and Veneer Association Test Records, except as noted. 2 Canadian Wood Council, Fire Safety Design in Buildings, 1996. 3 APA - The Engineered Wood Association Test Rcsulls. 4 Exposure I or exterior.

For additional information or assistance contact: American Wood Council 803 Sycolin Rd, Suite 20 J

Leesburg, VA 20175 http:// www.awc.orgl 202-46 3-2766

American Wood Council

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