ASTM D6305-21

Standard Practice for Calculating Bending Strength Design Adjustment Factors for Fire-Retardant-Treated Plywood Roof Sheathing

SIGNIFICANCE AND USE
5.1 This practice establishes the procedure to determine adjustment factors that account for the isolated effects of fire-retardant treatment on plywood roof sheathing. These effects are established relative to performance of untreated plywood. This practice uses data from reference thermal-load cycles designed to simulate temperatures in sloped roofs of common design to evaluate products for 50 iterations.  
5.2 This practice applies to material installed using construction practices recommended by the fire retardant chemical manufacturers that include avoiding exposure to precipitation, direct wetting, or regular condensation. This practice is not meant to apply to buildings with significantly different designs than those described in 1.3.  
5.3 Test Method D5516 caused thermally induced strength losses in laboratory simulations within a reasonably short period. The environmental conditions used in the laboratory-activated chemical reactions that are considered to be similar to those occurring in the field. This assumption is the fundamental basis of this practice.
SCOPE
1.1 This practice covers procedures for calculating adjustment factors that account for the effects of fire-retardant treatment on bending strength of plywood roof sheathing. The adjustment factors calculated in accordance with this practice are to be applied to design values for untreated plywood in order to determine design values for fire-retardant-treated plywood used as sheathing in roof systems. The methods establish the effect of treatment based upon matched bending strength testing of materials with and without treatment after exposure at elevated temperatures.
Note 1: This analysis focuses on the relative performance of treated and untreated materials tested after equilibrating to ambient conditions following a controlled exposure to specified conditions of high temperature and humidity. Elevated temperature, moisture, load duration, and other factors typically accounted for in the design of untreated plywood must also be considered in the design of fire-retardant-treated plywood roof sheathing, but are outside the scope of the treatment adjustments developed under this practice.  
1.2 It is assumed that the procedures will be used for fire-retardant-treated plywood installed using appropriate construction practices recommended by the fire retardant chemical manufacturers, which include avoiding exposure to precipitation, direct wetting, or regular condensation.  
1.3 This practice uses thermal load profiles reflective of exposures encountered in normal service conditions in a wide variety of continental United States climates. The heat gains, solar loads, roof slopes, ventilation rates, and other parameters used in this practice were chosen to reflect common sloped roof designs. This practice is applicable to roofs of 3 in 12 or steeper slopes, to roofs designed with vent areas and vent locations conforming to national standards of practice, and to designs in which the bottom side of the sheathing is exposed to ventilation air. These conditions may not apply to significantly different designs and therefore this practice may not apply to such designs.  
1.4 Information and a brief discussion supporting the provisions of this practice are in the Commentary in the appendix. A large, more detailed, separate Commentary is also available from ASTM.2  
1.5 The methodology in this practice is not meant to account for all reported instances of fire-retardant plywood undergoing premature heat degradation.  
1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety...

General Information

• Status: Published
• Publication Date: 31-May-2021
• ICS: 91.060.20 - Roofs
• Technical Committee: D07 - Wood
• Drafting Committee: D07.07 - Fire Performance of Wood

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6305 − 21
Standard Practice for
Calculating Bending Strength Design Adjustment Factors
1
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.4 Information and a brief discussion supporting the pro-
visionsofthispracticeareintheCommentaryintheappendix.
1.1 This practice covers procedures for calculating adjust-
Alarge, more detailed, separate Commentary is also available
ment factors that account for the effects of fire-retardant
2
from ASTM.
treatment on bending strength of plywood roof sheathing. The
1.5 Themethodologyinthispracticeisnotmeanttoaccount
adjustment factors calculated in accordance with this practice
for all reported instances of fire-retardant plywood undergoing
are to be applied to design values for untreated plywood in
premature heat degradation.
order to determine design values for fire-retardant-treated
plywood used as sheathing in roof systems. The methods
1.6 Thevaluesstatedininch-poundunitsaretoberegarded
establish the effect of treatment based upon matched bending
as standard. The values given in parentheses are mathematical
strength testing of materials with and without treatment after
conversions to SI units that are provided for information only
exposure at elevated temperatures.
and are not considered standard.
NOTE 1—This analysis focuses on the relative performance of treated
1.7 This standard does not purport to address all of the
and untreated materials tested after equilibrating to ambient conditions
safety concerns, if any, associated with its use. It is the
following a controlled exposure to specified conditions of high tempera-
responsibility of the user of this standard to establish appro-
ture and humidity. Elevated temperature, moisture, load duration, and
other factors typically accounted for in the design of untreated plywood priate safety, health, and environmental practices and deter-
must also be considered in the design of fire-retardant-treated plywood
mine the applicability of regulatory limitations prior to use.
roof sheathing, but are outside the scope of the treatment adjustments
1.8 This international standard was developed in accor-
developed under this practice.
dance with internationally recognized principles on standard-
1.2 It is assumed that the procedures will be used for
ization established in the Decision on Principles for the
fire-retardant-treated plywood installed using appropriate con-
Development of International Standards, Guides and Recom-
structionpracticesrecommendedbythefireretardantchemical mendations issued by the World Trade Organization Technical
manufacturers, which include avoiding exposure to
Barriers to Trade (TBT) Committee.
precipitation, direct wetting, or regular condensation.
2. Referenced Documents
1.3 This practice uses thermal load profiles reflective of
3
2.1 ASTM Standards:
exposures encountered in normal service conditions in a wide
D9Terminology Relating to Wood and Wood-Based Prod-
variety of continental United States climates. The heat gains,
ucts
solar loads, roof slopes, ventilation rates, and other parameters
D5516TestMethodforEvaluatingtheFlexuralPropertiesof
usedinthispracticewerechosentoreflectcommonslopedroof
Fire-Retardant Treated Softwood Plywood Exposed to
designs.Thispracticeisapplicabletoroofsof3in12orsteeper
Elevated Temperatures
slopes, to roofs designed with vent areas and vent locations
conforming to national standards of practice, and to designs in
3. Terminology
whichthebottomsideofthesheathingisexposedtoventilation
3.1 Definitions:
air. These conditions may not apply to significantly different
3.1.1 Definitionsusedinthispracticeareinaccordancewith
designs and therefore this practice may not apply to such
Terminology D9.
designs.
2
Commentary on this practice is available from ASTM Headquarters. Request
1
This practice is under the jurisdiction ofASTM Committee D07 on Wood and File No. D07–1004.
3
is the direct responsibility of Subcommittee D07.07 on Fire Performance of Wood. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedJune1,2021.PublishedJuly2021.Originallyapproved contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
ɛ1
in 1998. Last previous edition approved in 2015 as D6305–08(2015) . DOI: Standards volume information, refer to the standard’s Document
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: D6305 − 08 (Reapproved 2015) D6305 − 21
Standard Practice for
Calculating Bending Strength Design Adjustment Factors
1
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. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1
ε NOTE—Editorial corrections were made to Appendix X1 in October 2015.
1. Scope
1.1 This practice covers procedures for calculating bending strength design adjustment factors for fire-retardant-treated that
account for the effects of fire-retardant treatment on bending strength of plywood roof sheathing. The methods utilize the results
of strength testing after exposure at elevated temperatures and computer-generated thermal load profiles reflective of exposures
encountered in normal service conditions in a wide variety of continental United States climates.adjustment factors calculated in
accordance with this practice are to be applied to design values for untreated plywood in order to determine design values for
fire-retardant-treated plywood used as sheathing in roof systems. The methods establish the effect of treatment based upon matched
bending strength testing of materials with and without treatment after exposure at elevated temperatures.
NOTE 1—This analysis focuses on the relative performance of treated and untreated materials tested after equilibrating to ambient conditions following
a controlled exposure to specified conditions of high temperature and humidity. Elevated temperature, moisture, load duration, and other factors typically
accounted for in the design of untreated plywood must also be considered in the design of fire-retardant-treated plywood roof sheathing, but are outside
the scope of the treatment adjustments developed under this practice.
1.2 Necessarily, common laboratory practices were used to develop the methods herein. It is assumed that the procedures will be
used for fire-retardant-treated plywood installed using appropriate construction practices recommended by the fire retardant
chemical manufacturers, which include avoiding exposure to precipitation, direct wetting, or regular condensation.
1.3 This practice uses thermal load profiles reflective of exposures encountered in normal service conditions in a wide variety of
continental United States climates. The heat gains, solar loads, roof slopes, ventilation rates, and other parameters used in this
practice were chosen to reflect common sloped roof designs. This practice is applicable to roofs of 3 in 12 or steeper slopes, to
roofs designed with vent areas and vent locations conforming to national standards of practice, and to designs in which the bottom
side of the sheathing is exposed to ventilation air. These conditions may not apply to significantly different designs and therefore
this practice may not apply to such designs.
1.4 Information and a brief discussion supporting the provisions of this practice are in the Commentary in the appendix. A large,
2
more detailed, separate Commentary is also available from ASTM.
1.5 The methodology in this practice is not meant to account for all reported instances of fire-retardant plywood undergoing
premature heat degradation.
1
This practice is under the jurisdiction of ASTM Committee D07 on Wood and is the direct responsibility of Subcommittee D07.07 on Fire Performance of Wood.
Current edition approved Sept. 1, 2015June 1, 2021. Published October 2015July 2021. Originally approved in 1998. Last previous edition approved in 20082015 as
ɛ1
D6305 – 08.D6305 – 08(2015) . DOI: 10.1520/D6305-08R15E01.10.1520/D6305-21.
2
Commentary on this practice is available from ASTM Headquarters. Request File No. D07–1004.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6305 − 21
1.6 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthe
...