ASTM D6305-02e1

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Designation: D 6305 – 02
Standard Practice for
Calculating Bending Strength Design Adjustment Factors
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for Fire-Retardant-Treated Plywood Roof Sheathing
This standard is issued under the fixed designation D6305; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
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e NOTE—The title for Table 6 was corrected from “One” to “Three Exposure Temperatures” in October 2002.
1. Scope responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
1.1 This practice covers procedures for calculating bending
bility of regulatory limitations prior to use.
strength design adjustment factors for fire-retardant-treated
plywood roof sheathing. The methods utilize the results of
2. Referenced Documents
strength testing after exposure at elevated temperatures and
2.1 ASTM Standards:
computer-generated thermal load profiles reflective of expo-
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D9 Terminology Relating to Wood
sures encountered in normal service conditions in a wide
D5516 Test Method for Evaluating the Flexural Properties
variety of climates.
of Fire-Retardant Treated Softwood Plywood Exposed to
1.2 Necessarily, common laboratory practices were used to
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Elevated Temperatures
develop the methods herein. It is assumed that the procedures
will be used for fire-retardant-treated plywood installed using
3. Terminology
appropriate construction practices recommended by the fire
3.1 Definitions:
retardant chemical manufacturers, which include avoiding
3.1.1 Definitionsusedinthispracticeareinaccordancewith
exposure to precipitation, direct wetting, or regular condensa-
Terminology D9.
tion.
3.2 Definitions of Terms Specific to This Standard:
1.3 Theheatgains,solarloads,roofslopes,ventilationrates,
3.2.1 bin mean temperature—10°F (5.5°C) temperature
and other parameters used in this practice were chosen to
ranges having mean temperatures of 105 (41), 115 (46), 125
reflectcommonslopedroofdesigns.Thispracticeisapplicable
(52),135(57),145(63),155(68),165(74),and175°F(79°C).
toroofsof3in12orsteeperslopes,toroofsdesignedwithvent
areas and vent locations conforming to national standards of
4. Summary of Practice
practice and to designs in which the bottom side of the
4.1 The test data determined by Test Method D5516 are
sheathing is exposed to ventilation air. These conditions may
usedtodevelopadjustmentfactorsforfire-retardanttreatments
not apply to significantly different designs and therefore this
to apply to untreated-plywood design values. The test data are
practice may not apply to such designs.
used in conjunction with climate models and other factors and
1.4 Information and a brief discussion supporting the pro-
the practice thus extends laboratory strength data measured
visionsofthispracticeareintheCommentaryintheappendix.
after accelerated aging to design value recommendations.
Alarge, more detailed, separate Commentary is also available
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from ASTM.
5. Significance and Use
1.5 Themethodologyinthispracticeisnotmeanttoaccount
5.1 This practice develops treatment factors that shall be
for all reported instances of fire-retardant plywood undergoing
usedbyfireretardantchemicalmanufacturerstoadjustbending
premature heat degradation.
strengthdesignvaluesforuntreatedplywoodtoaccountforthe
1.6 Thispracticeiswrittenininch-poundunitswithSIunits
fire-retardant treatment effects. This practice uses data from
provided in parentheses for information only.
reference thermal-load cycles designed to simulate tempera-
1.7 This standard does not purport to address all of the
tures in sloped roofs of common design to evaluate products
safety concerns, if any, associated with its use. It is the
for 50 iterations.
5.2 This practice applies to material installed using con-
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This practice is under the jurisdiction ofASTM Committee D07 on Wood and structionpracticesrecommendedbythefireretardantchemical
is the direct responsibility of Subcommittee D07.07 on Fire Performance of Wood.
manufacturers that include avoiding exposure to precipitation,
Current edition approved April 10, 2002. Published June 2002. Originally
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published as D6305-98. Last previous edition D6305-98 .
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Commentary on this practice is available from ASTM Headquarters. Request
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File No. D07–1004. Annual Book of ASTM Standards, Vol 04.10.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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e1
D6305–02
direct wetting, or regular condensation. This practice is not 6.2.2 The intercept of the regression obtained in 6.2.1 for
meant to apply to buildi
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