ASTM D7746-11(2016)

Standard Practice for Calculating the Superimposed Load on Wood-frame Floor-Ceiling Assemblies for Standard Fire-Resistance Tests

SIGNIFICANCE AND USE
4.1 Test Methods E119, E1529, and other standard fire resistance test methods specify that throughout the fire-resistance test, a constant superimposed load shall be applied to a load-bearing test specimen to simulate a maximum load condition. This superimposed load shall be the maximum load allowed by design under nationally recognized structural design criteria for the tested floor configuration (that is, joist selection, spacing, and span).  
4.1.1 For this Practice, the nationally recognized structural design criteria to be used to determine the maximum load condition are those for allowable stress design in the NDS (National Design Specification for Wood Construction).  
4.1.2 Alternatively, the standard fire resistance test methods shall be permitted to be conducted by applying a load less than the maximum allowable load in 4.1.1 for the tested configuration; however, these tests shall be identified in the test report as being conducted under restricted loading conditions.  
4.2 This practice describes procedures for calculating the superimposed load to be applied in standard fire resistance tests of wood floor-ceiling assemblies. Practice D6513 provides a similar methodology for calculating the superimposed load on wood-frame walls.  
4.3 Statements in either the fire resistance test method standard or the nationally recognized structural design standard supersede any procedures described by this practice.  
4.4 The NDS shall be reviewed to ensure calculations are in compliance with all applicable provisions of that standard.
SCOPE
1.1 This practice covers procedures for calculating the superimposed load required to be applied to load-bearing wood-frame floor-ceiling assemblies throughout standard fire-resistance tests.  
1.2 These calculations determine the maximum superimposed load to be applied to the floor-ceiling assembly during the fire resistance test. The maximum superimposed load, calculated in accordance with nationally-recognized structural design criteria, shall be designed to induce the maximum allowable stress in the wood floor-ceiling fire test configuration being tested.  
1.3 This practice is only applicable to those wood-frame floor-ceiling assemblies for which the nationally recognized structural design criteria are the NDS (National Design Specification for Wood Construction).  
1.4 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.  
1.5 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this 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: 31-Jul-2016
• ICS: 13.220.50 - Fire-resistance of building materials and elements
• ICS: 79.080 - Semi-manufactures of timber
• Technical Committee: D07 - Wood
• Drafting Committee: D07.05 - Wood Assemblies

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: D7746 − 11 (Reapproved 2016)
Standard Practice for
Calculating the Superimposed Load on Wood-frame Floor-
Ceiling Assemblies for Standard Fire-Resistance Tests
This standard is issued under the fixed designation D7746; 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 D9Terminology Relating to Wood and Wood-Based Prod-
ucts
1.1 This practice covers procedures for calculating the
D6513Practice for Calculating the Superimposed Load on
superimposed load required to be applied to load-bearing
Wood-frame Walls for Standard Fire-Resistance Tests
wood-frame floor-ceiling assemblies throughout standard fire-
E119Test Methods for Fire Tests of Building Construction
resistance tests.
and Materials
1.2 These calculations determine the maximum superim-
E176Terminology of Fire Standards
posed load to be applied to the floor-ceiling assembly during
E1529Test Methods for Determining Effects of Large Hy-
the fire resistance test. The maximum superimposed load,
drocarbon Pool Fires on Structural Members and Assem-
calculated in accordance with nationally-recognized structural
blies
design criteria, shall be designed to induce the maximum
2.2 Other Standards:
allowablestressinthewoodfloor-ceilingfiretestconfiguration
NDSNational Design Specification for Wood Construction
being tested.
NDS SupplementDesign Values for Wood Construction
1.3 This practice is only applicable to those wood-frame
floor-ceiling assemblies for which the nationally recognized
3. Terminology
structural design criteria are the NDS (National Design Speci-
3.1 Definitions—Definitions used in this practice are in
fication for Wood Construction).
accordance with Terminology D9 and Terminology E176,
1.4 The text of this standard references notes and footnotes
unless otherwise indicated.
whichprovideexplanatorymaterial.Thesenotesandfootnotes
3.2 Definitions of Terms Specific to This Standard:
(excluding those in tables and figures) shall not be considered
3.2.1 gross area, n—section area calculated from overall
as requirements of the standard.
actual dimensions of member.
1.5 Thevaluesstatedininch-poundunitsaretoberegarded
3.2.2 net section area, n—sectionareacalculatedbydeduct-
asstandard.Nootherunitsofmeasurementareincludedinthis
ing from the gross section area the projected area of all
standard.
materials removed by boring, grooving, dapping, notching, or
1.6 This standard does not purport to address all of the
other means.
safety concerns, if any, associated with its use. It is the
3.2.3 superimposed load, n—the additional external load
responsibility of the user of this standard to establish appro-
needed to be applied to the assembly to result in the calculated
priate safety and health practices and determine the applica-
stresses within the assembly when any dead load of the
bility of regulatory limitations prior to use.
assembly itself is accounted for in the calculations.
2. Referenced Documents
4. Significance and Use
2.1 ASTM Standards:
4.1 Test Methods E119, E1529, and other standard fire
resistance test methods specify that throughout the fire-
resistancetest,aconstantsuperimposedloadshallbeappliedto
This practice is under the jurisdiction ofASTM Committee D07 on Wood and
a load-bearing test specimen to simulate a maximum load
is the direct responsibility of Subcommittee D07.05 on Wood Assemblies.
condition. This superimposed load shall be the maximum load
Current edition approved Aug. 1, 2016. Published August 2016. Original
allowed by design under nationally recognized structural
approved in 2011. Last previous edition approved in 2011 as D7746–11. DOI:
10.1520/D7746–11R16.
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 Available fromAmericanWood Council (AWC), 803 Sycolin Road, Suite 201,
the ASTM website. Leesburg, VA 20175, http://www.awc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7746 − 11 (2016)
design criteria for the tested floor configuration (that is, joist Supplement, product literature, or code evaluation report.
selection, spacing, and span). Reference design values: M, V, R , E, EI , and K for I-joists
r I min
4.1.1 For this Practice, the nationally recognized structural are given in the product literature, or code evaluation report.
design criteria to be used to determine the maximum load
6.2 Design Value Adjustments—Reference design values
condition are those for allowable stress design in the NDS
shall be multiplied by all applicable adjustment factors to
(National Design Specification for Wood Construction).
determine the adjusted design values. Additional adjustments
4.1.2 Alternatively,thestandardfireresistancetestmethods
may be required to address special design considerations for
shallbepermittedtobeconductedbyapplyingaloadlessthan
the specific member type. Not all factors may be applicable to
the maximum allowable load in 4.1.1 for the tested configura-
all product types.
tion;however,thesetestsshallbeidentifiedinthetestreportas
6.2.1 Bending—F for rectangular sections and M for
b
being conducted under restricted loading conditions.
I-joists shall be multiplied by all applicable NDS adjustment
4.2 This practice describes procedures for calculating the
factors including: C , C , C, C , C , C , C , C, C , C .
D M t L F V fu i r c
superimposedloadtobeappliedinstandardfireresistancetests
6.2.2 Compression parallel to the grain, F , shall be multi-
c
of wood floor-ceiling assemblies. Practice D6513 provides a
plied by all applicable NDS adjustment factors including: C ,
D
similar methodology for calculating the superimposed load on
C , C, C , C, and C .
M t F i P
wood-frame walls.
6.2.3 Shear parallel to grain—F for rectangular sections
v
4.3 Statements in either the fire resistance test method and V for I-joists shall be multiplied by all applicable NDS
standardorthenationallyrecognizedstructuraldesignstandard
adjustment factors including: C , C , C, C.
D M t i
supersede any procedures described by this practice.
6.2.4 Tension parallel to grain, F, shall be multiplied by all
t
applicable NDS adjustment factors including: C , C , C, C ,
4.4 TheNDSshallbereviewedtoensurecalculationsarein D M t F
C.
i
compliance with all applicable provisions of that standard.
6.2.5 Bearing:
5. Test Assumptions
6.2.5.1 Compression perpendicular-to-grain—F for rect-
c'
5.1 Floor Assembly—For design considerations, wood-
angular sections shall be multiplied by all applicable NDS
frame floor-ceiling assemblies consist of horizontal structural
adjustment factors including: C , C, C, C .
M t i b
members(thatis,joists),thefloordeckingorsheathing,andthe
6.2.5.2 I-joist Reference Design Reaction—R ,shallbemul-
r
perimeter rim boards.
tipliedbyallapplicableNDSadjustmentfactorsincluding: C ,
D
C , C.
5.2 Loading Conditions—Horizontal framing members sup- M t
6.2.6 Modulus of elasticity—E or E for rectangular sec-
port a vertical load that is uniformly distributed on the floor
min
tions and E and EI for I-joists shall be multiplied by all
assembly.Itisassumedthatloadapplicationsystemforthetest
I min
applicable NDS adjustment factors including: C , C, C, C .
distributes load between and along framing members in a
M t i T
manner consistent with a uniform load assumption and pro-
6.3 Adjustment Factors for Design Values—The following
vides load distribution to members that is representative of the
adjustment factors are to be assumed by default. If values less
end-use application.
thanthoselistedbelowareemployed,thentheappropriateload
NOTE 1—The calculation procedure in this standard is not appropriate restrictionshallbereportedinthetestreportandusedtoadjust
for a test that uses a load application system that incorporates discrete
the design bending and shear capacity in application:
point load distribution beams or frames with spanning capabilities that
6.3.1 Load duration factor, C , is 1.0.
D
servetoartificiallyre-distributeloadfromafailingmembertotheadjacent
6.3.2 Wet service factor, C , is 1.0.
framing. Such a system would require a higher load to be applied that
M
considers the enhanced load-sharing between members provided by the
6.3.3 Temperature factor, C, is 1.0.
t
load frame and the departure from a uniform load condition.An example
6.3.4 Beam stability factor, C , is 1.0 for a single span,
L
of a system that conforms to the calculation assumption would be one in
sheathed fire test assembly.
which each discrete load element (that is, dead weight pack, water barrel,
hydraulic cylinder, pneumatic cylinder, etc.) is applied to the floor at not 6.3.5 Size factor, C , is the value taken from tables in the
F
more than two locations along the length of the framing by distribution
NDS Supplement for the sawn lumber joist material in the test
beams that span across not more than three framing members.
assembly.
5.3 Lateral or torsional end support, including but not
6.3.6 Volume factor, C , per NDS provisions for glued-
V
limited to bridging, blocking, or bracing, shall be provided at
laminated timber members. The value of C for structural
v
pointsofbearingtopreventrotation.Whenadditionallateralor
composite lumber shall be defined by the product literature or
torsional support is used away from the ends to enhance
code evaluation report.The value o
...

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: D7746 − 11 D7746 − 11 (Reapproved 2016)
Standard Practice for
Calculating the Superimposed Load on Wood-frame Floor-
Ceiling Assemblies for Standard Fire-Resistance Tests
This standard is issued under the fixed designation D7746; 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 the superimposed load required to be applied to load-bearing wood-frame
floor-ceiling assemblies throughout standard fire-resistance tests.
1.2 These calculations determine the maximum superimposed load to be applied to the floor-ceiling assembly during the fire
resistance test. The maximum superimposed load, calculated in accordance with nationally-recognized structural design criteria,
shall be designed to induce the maximum allowable stress in the wood floor-ceiling fire test configuration being tested.
1.3 This practice is only applicable to those wood-frame floor-ceiling assemblies for which the nationally recognized structural
design criteria are the NDS (National Design Specification for Wood Construction).
1.4 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the standard.
1.5 The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this
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
2.1 ASTM Standards:
D9 Terminology Relating to Wood and Wood-Based Products
D6513 Practice for Calculating the Superimposed Load on Wood-frame Walls for Standard Fire-Resistance Tests
E119 Test Methods for Fire Tests of Building Construction and Materials
E176 Terminology of Fire Standards
E1529 Test Methods for Determining Effects of Large Hydrocarbon Pool Fires on Structural Members and Assemblies
2.2 Other Standards:
NDS National Design Specification for Wood Construction
NDS Supplement Design Values for Wood Construction
3. Terminology
3.1 Definitions—Definitions used in this practice are in accordance with Terminology D9 and Terminology E176, unless
otherwise indicated.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 gross area, n—section area calculated from overall actual dimensions of member.
3.2.2 net section area, n—section area calculated by deducting from the gross section area the projected area of all materials
removed by boring, grooving, dapping, notching, or other means.
This practice is under the jurisdiction of ASTM Committee D07 on Wood and is the direct responsibility of Subcommittee D07.05 on Wood Assemblies.
Current edition approved Nov. 15, 2011Aug. 1, 2016. Published March 2012August 2016. Original approved in 2011. Last previous edition approved in 2011 as D7746–11.
DOI: 10.1520/D7746–11.10.1520/D7746–11R16.
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.
Available from American Wood Council (AWC), 803 Sycolin Road, Suite 201, Leesburg, VA 20175, http://www.awc.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7746 − 11 (2016)
3.2.3 superimposed load, n—the additional external load needed to be applied to the assembly to result in the calculated stresses
within the assembly when any dead load of the assembly itself is accounted for in the calculations.
4. Significance and Use
4.1 Test Methods E119, E1529, and other standard fire resistance test methods specify that throughout the fire-resistance test,
a constant superimposed load shall be applied to a load-bearing test specimen to simulate a maximum load condition. This
superimposed load shall be the maximum load allowed by design under nationally recognized structural design criteria for the
tested floor configuration (that is, joist selection, spacing, and span).
4.1.1 For this Practice, the nationally recognized structural design criteria to be used to determine the maximum load condition
are those for allowable stress design in the NDS (National Design Specification for Wood Construction).
4.1.2 Alternatively, the standard fire resistance test methods shall be permitted to be conducted by applying a load less than
the maximum allowable load in 4.1.1 for the tested configuration; however, these tests shall be identified in the test report as being
conducted under restricted loading conditions.
4.2 This practice describes procedures for calculating the superimposed load to be applied in standard fire resistance tests of
wood floor-ceiling assemblies. Practice D6513 provides a similar methodology for calculating the superimposed load on
wood-frame walls.
4.3 Statements in either the fire resistance test method standard or the nationally recognized structural design standard supersede
any procedures described by this practice.
4.4 The NDS shall be reviewed to ensure calculations are in compliance with all applicable provisions of that standard.
5. Test Assumptions
5.1 Floor Assembly—For design considerations, wood-frame floor-ceiling assemblies consist of horizontal structural members
(that is, joists), the floor decking or sheathing, and the perimeter rim boards.
5.2 Loading Conditions—Horizontal framing members support a vertical load that is uniformly distributed on the floor
assembly. It is assumed that load application system for the test distributes load between and along framing members in a manner
consistent with a uniform load assumption and provides load distribution to members that is representative of the end-use
application.
NOTE 1—The calculation procedure in this standard is not appropriate for a test that uses a load application system that incorporates discrete point load
distribution beams or frames with spanning capabilities that serve to artificially re-distribute load from a failing member to the adjacent framing. Such
a system would require a higher load to be applied that considers the enhanced load-sharing between members provided by the load frame and the
departure from a uniform load condition. An example of a system that conforms to the calculation assumption would be one in which each discrete load
element (that is, dead weight pack, water barrel, hydraulic cylinder, pneumatic cylinder, etc.) is applied to the floor at not more than two locations along
the length of the framing by distribution beams that span across not more than three framing members.
5.3 Lateral or torsional end support, including but not limited to bridging, blocking, or bracing, shall be provided at points of
bearing to prevent rotation. When additional lateral or torsional support is used away from the ends to enhance performance of
the floor-ceiling assembly, description and locations of the support shall be reported
5.4 Where required to ensure that bearing capacity does not limit the test load, stiffeners or an increased bearing length shall
be permitted at the bearing locations to increase capacity.
6. Design Load Calculations
6.1 Design Values—-Reference design values: F ,F ,F ,E and E for rectangular sections are given in the NDS Supplement,
b v c' min
product literature, or code evaluation report. Reference design values: M,V,R ,E ,EI , and K for I-joists are given in the product
r I min
literature, or code evaluation report.
6.2 Design Value Adjustments—Reference design values shall be multiplied by all applicable adjustment factors to determine
the adjusted design values. Additional adjustments may be required to address special design considerations for the specific
member type. Not all factors may be applicable to all product types.
6.2.1 Bending—F for rectangular sections and M for I-joists shall be multiplied by all applicable NDS adjustment factors
b
including: C ,C ,C ,C ,C ,C ,C ,C ,C ,C .
D M t L F V fu i r c
6.2.2 Compression parallel to the grain, F , shall be multiplied by all applicable NDS adjustment factors including:
c
C ,C ,C ,C ,C , and C .
D M t F i P
6.2.3 Shear parallel to grain—F for rectangular sections and V for I-joists shall be multiplied by all applicable NDS adjustment
v
factors including: C ,C ,C ,C .
D M t i
6.2.4 Tension parallel to grain, F , shall be multiplied by all applicable NDS adjustment factors including: C ,C ,C ,C ,C .
t D M t F i
6.2.5 Bearing:
6.2.5.1 Compression perpendicular-to-grain—F for rectangular sections shall be multiplied by all applicable NDS adjustment
c'
factors including: C ,C ,C ,C .
M t i b
D7746 − 11 (2016)
6.2.5.2 I-joist Reference Design Reaction—R , shall be multiplied by all applicable NDS adjustment factors including:
r
C ,C ,C .
D M t
6.2.6 Modulus of elasticity—E or E for rectangular sections and E and EI for I-joists shall be multiplied by all applicable
min I min
NDS adjustment factors including: C ,C ,C ,C .
M t i T
6.3 Adjustment Factors for Design Values—The following adjustment factors are to be assumed by default. If values less than
those listed below are employed, then the appropriate load restriction shall be reported in th
...