ASTM D6841-15

Standard Practice for Calculating Design Value Treatment Adjustment Factors for Fire-Retardant-Treated Lumber

SIGNIFICANCE AND USE
5.1 Fire-retardant-treatments are used to reduce the flame-spread characteristics of wood. Chemicals and redrying conditions employed in treatments are known to modify the strength properties of the wood product being treated. This practice gives procedures for fire-retardant chemical manufacturers to use to calculate the effects of their treatment on lumber used in normal and elevated temperature service conditions.  
5.2 The effect of fire-retardant treatments on the strength of lumber used in roof framing applications is time related. In this practice, the cumulative effect on strength of annual thermal loads from all temperature bins is increased 50 times to establish treatment adjustment factors for fire-retardant treated lumber roof framing.  
5.3 The procedures of Test Method D5664 employ an elevated temperature intended to produce strength losses in a short period of time. Although the exposure is much more severe than that which occurs in an actual roof system, the chemical reactions that occur in the laboratory test are considered to be the same as those occurring over long periods of time in the field.  
5.4 Treatment adjustment factors developed under this practice apply to lumber installed in accordance with construction practices recommended by the fire-retardant chemical manufacturer which include avoidance of direct wetting, precipitation or frequent condensation. Application of this practice is limited to roof applications with design consistent with 1.3.
SCOPE
1.1 This practice covers procedures for calculating treatment adjustment factors to be applied to design values for fire-retardant-treated lumber used at ambient temperatures [service temperatures up to 100°F (38°C)] and as framing in roof systems.  
1.2 These design value treatment adjustment factors for the properties of extreme fiber in bending, tension parallel to grain, compression parallel to grain, horizontal shear, and modulus of elasticity are based on the results of strength tests of matched treated and untreated small clear wood specimens after conditioning at nominal room temperatures [72°F (22°C)] and of other similar specimens after exposure at 150°F (66°C). The test data are developed in accordance with Test Method D5664. Guidelines are provided for establishing adjustment factors for the property of compression perpendicular to grain and for connection design values.  
1.3 Treatment adjustment factors for roof framing applications are based on computer generated thermal load profiles for normal wood roof construction used in a variety of climates as defined by weather tapes of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE).2 The solar loads, moisture conditions, ventilation rates, and other parameters used in the computer model were selected to represent typical sloped roof designs. The thermal loads in this practice are applicable to roof slopes of 3 in 12 or steeper, 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 roof sheathing is exposed to ventilation air. For designs that do not have one or more of these base-line features, the applicability of this practice needs to be documented by the user.  
1.4 The procedures of this practice parallel those given in Practice D6305. General references and commentary in Practice D6305 are also applicable to this practice.  
1.5 The values stated in inch-pound units are to be regarded as standard. The SI units listed in parentheses are provided for information only and are not considered standard.  
1.6 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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 30-Nov-2015
• ICS: 13.220.50 - Fire-resistance of building materials and elements
• ICS: 79.040 - Wood, sawlogs and sawn timber
• Technical Committee: D07 - Wood
• Drafting Committee: D07.07 - Fire Performance of Wood

Relations

• Replaces: ASTM D6841-08 - Standard Practice for Calculating Design Value Treatment Adjustment Factors for Fire-Retardant-Treated Lumber
• Effective Date: 01-Dec-2015
• Referred By: ASTM D8223-19 - Standard Practice for Evaluation of Fire-Retardant Treated Laminated Veneer Lumber
• Effective Date: 01-Dec-2015
• Referred By: ASTM D5664-17 - Standard Test Method for Evaluating the Effects of Fire-Retardant Treatments and Elevated Temperatures on Strength Properties of Fire-Retardant Treated Lumber
• Effective Date: 01-Dec-2015

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6841 − 15
StandardPractice for
Calculating Design Value Treatment Adjustment Factors for
1
Fire-Retardant-Treated Lumber
This standard is issued under the fixed designation D6841; 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 The procedures of this practice parallel those given in
Practice D6305. General references and commentary in Prac-
1.1 This practice covers procedures for calculating treat-
tice D6305 are also applicable to this practice.
ment adjustment factors to be applied to design values for
1.5 Thevaluesstatedininch-poundunitsaretoberegarded
fire-retardant-treated lumber used at ambient temperatures
as standard. The SI units listed in parentheses are provided for
[service temperatures up to 100°F (38°C)] and as framing in
information only and are not considered standard.
roof systems.
1.6 This standard does not purport to address all of the
1.2 These design value treatment adjustment factors for the
safety concerns, if any, associated with its use. It is the
propertiesofextremefiberinbending,tensionparalleltograin,
responsibility of the user of this standard to establish appro-
compressionparalleltograin,horizontalshear,andmodulusof
priate safety and health practices and determine the applica-
elasticity are based on the results of strength tests of matched
bility of regulatory limitations prior to use.
treated and untreated small clear wood specimens after condi-
tioning at nominal room temperatures [72°F (22°C)] and of
2. Referenced Documents
other similar specimens after exposure at 150°F (66°C). The
3
testdataaredevelopedinaccordancewithTestMethodD5664.
2.1 ASTM Standards:
Guidelines are provided for establishing adjustment factors for
D9Terminology Relating to Wood and Wood-Based Prod-
the property of compression perpendicular to grain and for
ucts
connection design values.
D5664Test Method for Evaluating the Effects of Fire-
Retardant Treatments and Elevated Temperatures on
1.3 Treatment adjustment factors for roof framing applica-
Strength Properties of Fire-Retardant Treated Lumber
tionsarebasedoncomputergeneratedthermalloadprofilesfor
D6305Practice for Calculating Bending Strength Design
normal wood roof construction used in a variety of climates as
Adjustment Factors for Fire-Retardant-Treated Plywood
defined by weather tapes of the American Society of Heating,
Roof Sheathing
Refrigerating and Air-Conditioning Engineers, Inc.
2
(ASHRAE). The solar loads, moisture conditions, ventilation
3. Terminology
rates, and other parameters used in the computer model were
selected to represent typical sloped roof designs. The thermal
3.1 Definitions:
loads in this practice are applicable to roof slopes of 3 in 12 or
3.1.1 Definitionsusedinthispracticeareinaccordancewith
steeper, to roofs designed with vent areas and vent locations
Terminology D9.
conforming to national standards of practice and to designs in
3.2 Definitions of Terms Specific to This Standard:
which the bottom side of the roof sheathing is exposed to
3.2.1 bin mean temperature—10°F (5.5°C) temperature
ventilation air. For designs that do not have one or more of
ranges having mean temperatures of 105 (41), 115 (46), 125
these base-line features, the applicability of this practice needs
(52), 135 (57), 145 (63), 155 (68), 165 (74), 175 (79), and
to be documented by the user.
185°F (85°C).
3.2.2 thermal load profile—the cumulative time per year in
each 10°F (5.5°C) temperature bin.
1
This practice is under the jurisdiction ofASTM Committee D07 on Wood and
is the direct responsibility of Subcommittee D07.07 on Fire Performance of Wood.
Current edition approved Dec. 1, 2015. Published February 2016. Originally
approved in 2002. Last previous edition approved in 2008 as D6841–08. DOI:
3
10.1520/D6841-15. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
2
Available from American Society of Heating, Refrigerating, and Air- contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA Standards volume information, refer to the standard’s Document Summary page on
30329, http://www.ashrae.org. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D6841 − 15
4. Summary of Practice controlled environment of 150 64°F (66 62°C) and ≥50%
relative humidity (RH). Durations of exposure are 36, 72, and
4.1 Test results developed in accordance with Test Method
108 days.
D5664 are
...

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.
Designation: D6841 − 08 D6841 − 15
Standard Practice for
Calculating Design Value Treatment Adjustment Factors for
1
Fire-Retardant-Treated Lumber
This standard is issued under the fixed designation D6841; 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. Scope
1.1 This practice covers procedures for calculating treatment adjustment factors to be applied to design values for
fire-retardant-treated lumber used at ambient temperatures [service temperatures up to 100°F (38°C)] and as framing in roof
systems.
1.2 These design value treatment adjustment factors for the properties of extreme fiber in bending, tension parallel to grain,
compression parallel to grain, horizontal shear, and modulus of elasticity are based on the results of strength tests of matched
treated and untreated small clear wood specimens after conditioning at nominal room temperatures [72°F (22°C)] and of other
similar specimens after exposure at 150°F (66°C). The test data are developed in accordance with Test Method D5664. Guidelines
are provided for establishing adjustment factors for the property of compression perpendicular to grain and for connection design
values.
1.3 Treatment adjustment factors for roof framing applications are based on computer generated thermal load profiles for normal
wood roof construction used in a variety of climates as defined by weather tapes of the American Society of Heating, Refrigerating
2
and Air-Conditioning Engineers, Inc. (ASHRAE). The solar loads, moisture conditions, ventilation rates, and other parameters
used in the computer model were selected to represent typical sloped roof designs. The thermal loads in this practice are applicable
to roof slopes of 3 in 12 or steeper, 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 roof sheathing is exposed to ventilation air. For designs that do not have one or
more of these base-line features, the applicability of this practice needs to be documented by the user.
1.4 The procedures of this practice parallel those given in Practice D6305. General references and commentary in Practice
D6305 are also applicable to this practice.
1.5 The values stated in inch-pound units are to be regarded as standard. The SI units listed in parentheses are provided for
information only and are not considered standard.
1.6 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
3
2.1 ASTM Standards:
D9 Terminology Relating to Wood and Wood-Based Products
D5664 Test Method for Evaluating the Effects of Fire-Retardant Treatments and Elevated Temperatures on Strength Properties
of Fire-Retardant Treated Lumber
D6305 Practice for Calculating Bending Strength Design Adjustment Factors for Fire-Retardant-Treated Plywood Roof
Sheathing
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, 2008Dec. 1, 2015. Published September 2008February 2016. Originally approved in 2002. Last previous edition approved in 20032008
as D6841 – 03.D6841 – 08. DOI: 10.1520/D6841-08.10.1520/D6841-15.
2
Available from American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE), 1791 Tullie Circle, NE, Atlanta, GA 30329,
http://www.ashrae.org.
3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
D6841 − 15
3. Terminology
3.1 Definitions:
3.1.1 Definitions used in this practice are in accordance with Terminology D9.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 bin mean temperature—10°F (5.5°C) temperature ranges having mean temperatures of 105 (41), 115
...