ASTM D7032-21

Standard Specification for Establishing Performance Ratings for Wood-Plastic Composite and Plastic Lumber Deck Boards, Stair Treads, Guards, and Handrails

ABSTRACT
This specification presents the standard procedures for establishing the performance rating of wood-plastic composite (WPC) deck boards and guardrail systems (guards or handrails). The purpose of this specification is to establish the basis for code recognition of these products or systems in exterior applications where combustible construction is allowed. The general requirements foe these products shall be dictated by their performance in the following test methods: flesural tests; temperature and moisture effects; ultraviolet resistance test; freeze-thaw resistance test; biodeterioration tests; and fire performance tests. Deck boards shall additionally examined by: creep-recovery test; determination of unadjusted allowable load; mechanical fastener holding tests; and slip resistance test. In the same manner, guards and handrails shall additionally be analyzed through concentrated load tests, and one- and two-family dwelling requirements.
SCOPE
1.1 This specification covers procedures to establish a performance rating for wood-plastic composite and plastic lumber for use as exterior deck boards, stair treads, guards, and handrails. The purpose of this specification is to establish a basis for code recognition of these products or systems in exterior applications.
Note 1: While wood-plastic composites contain wood or other cellulosic materials, the presence of wood or other cellulosic materials in plastic lumber is not required by this specification. Due to non-wood materials in wood-plastic composites and plastic lumber the structural, physical, fire, and other attributes may not be similar to those of wood.
Note 2: The products addressed in this standard are considered combustible. No fire response characteristic is required in this specification except for flame spread index as determined in accordance with Test Method E84.  
1.1.1 The plastic component of wood-plastic composites and plastic lumber covered by this specification shall consist primarily of thermoplastics.  
1.2 Deck boards, stair treads, guards, and handrails covered by this specification are permitted to be of any code compliant shape and thickness (solid or non-solid).  
1.3 Wood-plastic composites and plastic lumber are produced in a broad range of fiber and/or resin formulations. It is recognized that the performance requirements in this specification are valid for any material or combination of materials used as deck boards, stair treads, guards, or handrails.  
1.4 Details of manufacturing processes are beyond the scope of this specification.  
1.5 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.  
1.6 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 Table of Contents:    
Section  
Scope  
1  
Referenced Documents  
2  
Terminology  
3  
General Requirements  
4  
Sampling  
4.1  
Sample Size  
4.2  
Conditioning  
4.3  
Flexural Tests  
4.4  
Temperature and Moisture Effects  
4.5  
Ultraviolet (UV) Resistance Test  
4.6  
Freeze-Thaw Resistance Test  
4.7  
Biodeterioration Tests  
4.8  
Fire Performance Tests  
4.9  
Deck Board Performance Requirements  
5  
General  
5.1  
Flexural Performance Tests  
5.2  
Determination of the Unadjusted Allowable Load  
5.3  
Creep-Recovery Test  
5.4  
Mechanical Fastener Holding Tests  
5.5  
Slip Resistance Test  
5.6  
Guard and Handrail Performance Requirements  
6  
General  
6.1  
Guardrail System Test Requirements  
6.2  
One- and Two-Family Dwelling Requirements...

General Information

• Status: Published
• Publication Date: 31-Oct-2021
• ICS: 79.080 - Semi-manufactures of timber
• Technical Committee: D07 - Wood
• Drafting Committee: D07.02 - Lumber and Engineered Wood Products

Relations

• Refers: ASTM D883-24 - Standard Terminology Relating to Plastics
• Effective Date: 01-Feb-2024
• Refers: ASTM D6109-24 - Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastic Lumber and Related Products
• Effective Date: 01-Feb-2024
• Refers: ASTM E84-23d - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Dec-2023
• Refers: ASTM D883-23 - Standard Terminology Relating to Plastics
• Effective Date: 01-Nov-2023
• Refers: ASTM D2565-23 - Standard Practice for Xenon-Arc Exposure of Plastics Intended for Outdoor Applications
• Effective Date: 01-Oct-2023
• Refers: ASTM E84-23c - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Sep-2023
• Refers: ASTM D1761-20 - Standard Test Methods for Mechanical Fasteners in Wood and Wood-Based Materials
• Effective Date: 15-Apr-2020
• Refers: ASTM D883-20 - Standard Terminology Relating to Plastics
• Effective Date: 01-Jan-2020
• Refers: ASTM D1929-19 - Standard Test Method for Determining Ignition Temperature of Plastics
• Effective Date: 01-Dec-2019
• Refers: ASTM D883-19c - Standard Terminology Relating to Plastics
• Effective Date: 01-Aug-2019
• Refers: ASTM E84-19b - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 01-Jul-2019
• Refers: ASTM E84-19a - Standard Test Method for Surface Burning Characteristics of Building Materials
• Effective Date: 15-Apr-2019
• Refers: ASTM D883-19a - Standard Terminology Relating to Plastics
• Effective Date: 15-Apr-2019
• Refers: ASTM D4761-19 - Standard Test Methods for Mechanical Properties of Lumber and Wood-Based Structural Materials
• Effective Date: 01-Apr-2019
• Refers: ASTM D6109-19 - Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastic Lumber and Related Products
• Effective Date: 01-Apr-2019

Overview

ASTM D7032-21 is a key standard by ASTM International for establishing performance ratings of wood-plastic composite (WPC) and plastic lumber deck boards, stair treads, guards, and handrails used in exterior applications. By outlining standardized testing and evaluation procedures, the standard provides the framework necessary for code recognition and ensures that WPC and plastic lumber products are safe and reliable for use in residential and commercial outdoor structures. It also addresses the diverse compositions and properties of WPC and plastic lumber, differentiating them from traditional wood products.

Key Topics

ASTM D7032-21 covers a comprehensive set of requirements and test methods to assess the suitability and durability of WPC and plastic lumber in exterior structural applications. The standard emphasizes:

• Flexural Testing: Determining strength and stiffness for deck boards, guards, and handrails.
• Environmental Stability: Assessing performance under temperature and moisture variations, ultraviolet (UV) exposure, and freeze-thaw cycles.
• Biodeterioration Resistance: Evaluating resistance to fungal decay and termite attack for products containing wood or other biodegradable content.
• Fire Performance: Ensuring flame spread index meets minimum criteria.
• Mechanical Performance: Including creep-recovery behavior, mechanical fastener holding, and slip resistance for deck boards.
• Structural Integrity: Additional concentrated load and dwelling-specific criteria for guards and handrails.
• Quality Assurance: Emphasizing regular product sampling, third-party inspection, and tailored manufacturing standards.

Applications

ASTM D7032-21 is directly relevant to manufacturers, designers, and builders involved in specifying and using wood-plastic composite and plastic lumber for outdoor decks, stairways, and safety barriers. Its practical applications include:

• Decking: Establishes structural and safety benchmarks for WPC/plastic deck boards, ensuring proper flexural strength and resistance to weathering and decay.
• Stair Treads: Addresses essential load capacity and slip resistance, contributing to stairway safety.
• Guards and Handrails: Sets out test protocols to ensure these critical safety features can withstand both uniform and concentrated loads, providing peace of mind in residential and commercial installations.
• Product Evaluation and Code Compliance: Enables manufacturers to demonstrate compliance with local building codes and regulatory requirements, supporting the acceptance of innovative composite products.
• Quality Control and Certification: Facilitates third-party certification and ongoing quality assurance through independent inspection, fostering consistent product performance.

Related Standards

ASTM D7032-21 references and aligns with a range of related standards for comprehensive product evaluation. Key related ASTM standards include:

• ASTM D4761 and ASTM D6109: Test methods for flexural properties of wood and plastics.
• ASTM D2915: Sampling and data analysis in structural wood products.
• ASTM D1761: Mechanical fasteners in wood-based materials.
• ASTM E84: Surface burning characteristics, critical for assessing flame spread index.
• ASTM D2394: Slip resistance testing for flooring surfaces.
• AWPA Standards E1/E10: Termite and fungal resistance evaluations.
• 2009 International Building Code (IBC) and International Residential Code (IRC): Referenced for specific structural performance and safety criteria.

Incorporating ASTM D7032-21 into project specifications helps ensure that structures using WPC and plastic lumber components meet necessary safety, durability, and code compliance requirements for exterior applications. This standard plays a vital role in expanding the use of advanced composite materials in decking and safety rail systems, supporting innovation while prioritizing public safety.

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: D7032 −21
Standard Specification for
Establishing Performance Ratings for Wood-Plastic
Composite and Plastic Lumber Deck Boards, Stair Treads,
Guards, and Handrails
This standard is issued under the fixed designation D7032; 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 1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This specification covers procedures to establish a
responsibility of the user of this standard to establish appro-
performance rating for wood-plastic composite and plastic
priate safety, health, and environmental practices and deter-
lumberforuseasexteriordeckboards,stairtreads,guards,and
mine the applicability of regulatory limitations prior to use.
handrails. The purpose of this specification is to establish a
1.7 Table of Contents:
basis for code recognition of these products or systems in
Section
exterior applications.
Scope 1
Referenced Documents 2
NOTE 1—While wood-plastic composites contain wood or other cellu-
Terminology 3
losic materials, the presence of wood or other cellulosic materials in
General Requirements 4
plastic lumber is not required by this specification. Due to non-wood
Sampling 4.1
materials in wood-plastic composites and plastic lumber the structural,
Sample Size 4.2
physical, fire, and other attributes may not be similar to those of wood.
Conditioning 4.3
NOTE 2—The products addressed in this standard are considered
Flexural Tests 4.4
combustible. No fire response characteristic is required in this specifica-
Temperature and Moisture Effects 4.5
tion except for flame spread index as determined in accordance with Test
Ultraviolet (UV) Resistance Test 4.6
Method E84. Freeze-Thaw Resistance Test 4.7
Biodeterioration Tests 4.8
1.1.1 The plastic component of wood-plastic composites
Fire Performance Tests 4.9
and plastic lumber covered by this specification shall consist Deck Board Performance Requirements 5
General 5.1
primarily of thermoplastics.
Flexural Performance Tests 5.2
Determination of the Unadjusted Allowable 5.3
1.2 Deck boards, stair treads, guards, and handrails covered
Load
by this specification are permitted to be of any code compliant
Creep-Recovery Test 5.4
shape and thickness (solid or non-solid).
Mechanical Fastener Holding Tests 5.5
Slip Resistance Test 5.6
1.3 Wood-plastic composites and plastic lumber are pro-
Guard and Handrail Performance 6
duced in a broad range of fiber and/or resin formulations. It is Requirements
General 6.1
recognized that the performance requirements in this specifi-
Guardrail System Test Requirements 6.2
cation are valid for any material or combination of materials
One- and Two-Family Dwelling 6.2.1.1
used as deck boards, stair treads, guards, or handrails. Requirements
Handrail Test Requirements (Concentrated 6.3
1.4 Details of manufacturing processes are beyond the
Load)
Report 7
scope of this specification.
Independent Inspection 8
1.5 The values stated in inch-pound units are to be regarded Manufacturing Standard 9
Precision and Bias 10
as standard. The values given in parentheses are mathematical
Keywords 11
conversions to SI units that are provided for information only
Two-Span Test Method Annex A1
and are not considered standard. Commentary Appendix X1
1.8 This international standard was developed in accor-
dance with internationally recognized principles on standard-
This specification is under the jurisdiction ofASTM Committee D07 on Wood
andisthedirectresponsibilityofSubcommitteeD07.02onLumberandEngineered
ization established in the Decision on Principles for the
Wood Products.
Development of International Standards, Guides and Recom-
Current edition approved Nov. 1, 2021. Published December 2021. Originally
mendations issued by the World Trade Organization Technical
approved in 2004. Last previous edition approved in 2017 as D7032–17. DOI:
10.1520/D7032-21. Barriers to Trade (TBT) Committee.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7032 − 21
2. Referenced Documents G154Practice for Operating Fluorescent Ultraviolet (UV)
2 Lamp Apparatus for Exposure of Nonmetallic Materials
2.1 ASTM Standards:
D9Terminology Relating to Wood and Wood-Based Prod- 2.2 Other References:
AWPAStandard E1Standard Method for Laboratory Evalu-
ucts
D790Test Methods for Flexural Properties of Unreinforced ation for Determination of Resistance to Subterranean
Termites
and Reinforced Plastics and Electrical Insulating Materi-
AWPA Standard E10Standard Method of Testing Wood
als
Preservatives by Laboratory Soil-Block Cultures
D883Terminology Relating to Plastics
2009 International Building Code International Code
D1037Test Methods for Evaluating Properties of Wood-
Council, Inc.
Base Fiber and Particle Panel Materials
2009 International Residential Code International Code
D1413Test Method for Wood Preservatives by Laboratory
3 5
Council, Inc.
Soil-Block Cultures (Withdrawn 2016)
D1554Terminology Relating to Wood-Base Fiber and Par-
3. Terminology
ticle Panel Materials
D1761Test Methods for Mechanical Fasteners in Wood and
3.1 Definitions—Terminology used to describe WPCs are
Wood-Based Materials
defined in Terminologies D9, D883, D1554, and D4092,
D1929Test Method for Determining Ignition Temperature
Practice D1972, and Classification D4000.
of Plastics
3.2 Definitions of Terms Specific to This Standard:
D1972Practice for Generic Marking of Plastic Products
3 3.2.1 center-point load—aflexuretestwheretheloadcomes
(Withdrawn 2014)
incontactwiththetestspecimenatalocationthatis ⁄2thetest
D2017TestMethodofAcceleratedLaboratoryTestofNatu-
3 span.
ral Decay Resistance of Woods (Withdrawn 2014)
3.2.2 guard—a building component or a system of building
D2047Test Method for Static Coefficient of Friction of
components located at or near the open sides of elevated
Polish-Coated Flooring Surfaces as Measured by the
walking surfaces that minimizes the possibility of a fall from
James Machine
the walking surface to a lower level.
D2394Test Methods for Simulated ServiceTesting ofWood
and Wood-Based Finish Flooring
3.2.3 handrail—a rail intended for grasping by the hand for
D2565Practice for Xenon-Arc Exposure of Plastics In-
guidance or support.
tended for Outdoor Applications
3.2.4 plastic lumber—amanufacturedproductmadeprimar-
D2915Practice for Sampling and Data-Analysis for Struc-
ily from plastic materials (filled or unfilled), typically used as
tural Wood and Wood-Based Products
a building material, which is usually rectangular in cross-
D3345Test Method for Laboratory Evaluation of Solid
section.
Wood for Resistance to Termites
3.2.5 quarter-point loading—a flexure test where the load
D4000Classification System for Specifying Plastic Materi-
comes in contact with the test specimen at two locations, each
als
of which is located at ⁄4 the span from the specimen load
D4092 Terminology for Plastics: Dynamic Mechanical
support.
Properties
3.2.5.1 Discussion—For example, quarter-point loading for
D4761Test Methods for Mechanical Properties of Lumber
a test specimen on a 24-in. (610-mm) span would have two
and Wood-Based Structural Materials
equalloadscontactthetestspecimeneachlocated6in.infrom
D5764Test Method for Evaluating Dowel-Bearing Strength
the test specimen load support. The distance between the two
of Wood and Wood-Based Products
points of load would be 12 in. (305 mm).
D6109TestMethodsforFlexuralPropertiesofUnreinforced
3.2.6 span rating—an index number that identifies the test
and Reinforced Plastic Lumber and Related Products
span used in all structural load testing, which is the maximum
D6662Specification for Polyolefin-Based Plastic Lumber
center-to-center support spacing for the specified end use, and
Decking Boards
allowable design capacity, in pounds per square foot (lbf/
E84Test Method for Surface Burning Characteristics of
2 2
ft (kN⁄m )), determined in accordance with this specification.
Building Materials
3.2.6.1 Discussion—For example, a deck span rating of
E1354Test Method for Heat and Visible Smoke Release
⁄100 recognizes the deck board for installation perpendicular
Rates for Materials and Products Using an Oxygen Con-
to the floor joists spaced a maximum of 16 in. (406 mm) on
sumption Calorimeter
center, and for supporting the load combinations required by
F1679Test Method for Using a Variable Incidence Tribom-
the applicable code, which in this case cannot exceed 100
eter (VIT) (Withdrawn 2006)
2 2
lbf/ft (4.79 kN/m ).
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 from American Wood-Preservers’ Association (AWPA), P.O. Box
the ASTM website. 361784, Birmingham, AL 35236-1784, http://www.awpa.com.
3 5
The last approved version of this historical standard is referenced on Available from International Code Council (ICC), 5203 Leesburg Pike, Suite
www.astm.org. 600, Falls Church, VA 22041-3401, http://www.intlcode.org.
D7032 − 21
3.2.7 third-point loading—a flexure test where the load R 50.00185 3L /d (1)
comes in contact with the test specimen at two locations, each
Formemberswherethedepth(verticaldimension)isvarying
of which is located at ⁄3 the span from the specimen load
along the member length, the depth (d) shall be taken as the
support.
gross member depth at the point of maximum moment.
3.2.7.1 Discussion—For example, third-point loading for a
NOTE3—Eq1isbasedonthemaximumextremefiberstrainatmidspan
testspecimenona24-in.(610-mm)spanwouldhavetwoequal
of a horizontally symmetric simple span member. For a product that is
loads contact the test specimen each located 8 in. in from the
symmetric about its horizontal axis, Eq 1 yields the target strain rate at
test specimen load support. The distance between the two
boththeextremetensileandextremecompressivefaces.Foraproductthat
points of load would also be 8 in. (205 mm).
is not symmetric about its horizontal axis, the Eq 1 strain rate is the
average of the strains at these faces. See Commentary for additional
3.2.8 wood-plastic composite (WPC)—a composite made
information.
primarily from wood- or cellulose-based materials and plas-
NOTE 4—Some wood-plastic composites and plastic lumber exhibit
tic(s).
exceptionally large deformations prior to failure in bending. Users are
cautioned to take particular care in test machine set-up to accommodate
large deflections, both in terms of deflection-measuring devices and
4. General Requirements
support conditions.
4.1 Sampling—Samplesfortestingshallberepresentativeof
4.4.1 Flexural Strength—Modulus of rupture (MOR)or
the population being evaluated. Sampling shall be representa-
momentcapacityshallbereportedforeachspecimen.Flexural
tive of the possible variations due to changes in raw materials
strength shall be calculated from the maximum load achieved
and process variables over time. It is essential to consider
or the load at 3% strain, whichever occurs first.
batch-to-batch and shift-to-shift variability when sampling
4.4.2 Flexural Stiffness—Apparent modulus of elasticity
actual production. Test specimens shall be selected from
(MOE)or EI shall be reported for each specimen. Flexural
several production runs of a given item. Products shall be
stiffnessshallbecalculatedfromalinearleastsquaresfitofthe
sampled at the manufacturing site by an accredited third party
stress-strain curve over the range of 10 to 40% of ultimate
inspectionagencyortestinglaboratory.Exceptionstosampling
stress.
atthemanufacturingsite,suchasatawarehouseordistribution
4.4.3 The flexural strength and stiffness for deck board,
center, shall be documented in the test report.
guard, and handrail materials shall be determined in accor-
4.2 Sample Size—Selection of a sample size depends upon
dance with 4.4 and shall be used to establish a standard
thepropertytobeestimated,theactualvariationintheproperty
baseline performance level for comparison with future produc-
occurring in the population, and the precision with which the
tion during the required quality control audits.
property is to be estimated. The principles of Practice D2915
4.5 Temperature and Moisture Effects:
shall be followed. The minimum sample size shall provide
4.5.1 Temperature Effect—Testing shall be conducted to
estimationofmeanvalueswithin5%inaccordancewith3.4.2
verify that allowable span and load ratings are applicable at a
of Practice D2915.
range of temperatures expected in service. For purposes of this
4.3 Conditioning—Prior to testing, all specimens shall be
specification, the lower and upper temperatures shall be -20 6
conditioned to environmental conditions appropriate for the
4°F (-29 6 2°C) and 125 6 4°F (52 6 2°C), respectively.
intended end use of the product. Alternatively, test specimens
Flexure tests shall be conducted to failure at the desired span.
shall be conditioned for a minimum of 40 h at 68°F 6 4°F
A minimum of 10 specimens shall be tested at each tempera-
(20°C 6 2°C) and 50 6 5% RH. If data show that product
ture. The flexural strength and stiffness shall be determined in
properties are not affected by extreme moisture conditions,
accordance with 4.4 and the average change in properties
suchassubmersion,thematerialshallbepermittedtobetested
between the flexural strength and stiffness of the control
without special conditioning. When the product is to be
flexural specimens and the specimens tested at low and high
subjectedtoawatersoakenvironment,thetestspecimensshall
temperatures shall be calculated as a percentage and reported.
be tested within 30 min upon removal from the treatment.
Theaveragechangeinflexuralstrengthandstiffnessproperties
4.4 Flexural Tests—Flexural strength and stiffness shall be shall be calculated by determining the difference between the
control and conditioned values and dividing that difference by
determined in accordance with principles of Test Methods
D4761 or D6109. Alternatively, to assess compliance with the control value.
performance requirements in its intended installed 4.5.2 Moisture Effect—Testing shall be conducted to verify
configuration, the deck boards shall be tested according to the that allowable span and load ratings are applicable at moisture
two-span method defined in Annex A1. The test specimen conditionsexpectedinservice.Flexuretestsshallbeconducted
cross section shall be the minimum anticipated structural size tofailureatthedesiredspan.Aminimumof10specimensshall
for the intended end use. The test span shall be that for which be tested at moisture conditions anticipated in service (for
coderecognitionisdesired.Thespecimensshallbeloadedata example, high humidity, submerged). The average maximum
constant strain rate of 1% per minute (610%).Average time flexural strength and stiffness shall be determined in accor-
to failure for each test configuration shall be recorded (see dance with 4.4. The average change in properties between the
Commentary,X1.2).Aconstantstrainrateof1%perminuteis control specimens and those tested at the in-service moisture
achieved by using a constant rate of test machine crosshead condition of interest shall be calculated as a percentage and
motion, R, (inches/minute) computed in terms of the test span, reported. The average change in flexural strength and stiffness
L, and the member depth, d, by the following equation: properties shall be calculated by determining the difference
D7032 − 21
between the control and conditioned values and dividing that 4.7.1 Aminimumoffive(5)exposedandfive(5)unexposed
difference by the control value. specimens shall be tested in accordance with 4.4. If more than
one component is being evaluated (for example, deck boards
4.5.3 Criteria—The most restrictive effect (either tempera-
and guard rail components) and all materials are manufactured
tureormoisture)shallbeusedtoadjusttheperformancerating
from the same materials, then freeze-thaw testing of only one
of deck boards, guardrails, and handrails. For deck boards, the
component is required.
deck board span (or load rating) shall be reduced by the most
4.7.2 Acceptance Criteria—The average change in proper-
restrictive effect determined from 4.5.1 or 4.5.2. For guards
ties between the exposed and unexposed specimens shall be
and handrails, if the most restrictive effect exceeds 25%, the
calculatedasapercentageandreported.Theaveragechangein
test loads for the guards or handrails shall be increased by the
flexural strength and stiffness properties shall be calculated by
amount in excess of 25%.
determiningthedifferencebetweenthecontrolandconditioned
4.6 Ultraviolet (UV) Resistance Test—To determine the
values and dividing that difference by the control value.
mechanicalpropertydegradeafterUVexposure,aminimumof
Condition of acceptance is the average flexural strength of
five (5) full-size or full-thickness specimens shall be exposed
exposedtestspecimensandshallbewithin10%oftheaverage
to a minimum of 2000 h accelerated weathering in accordance
flexural strength of unexposed specimens. For deck boards, if
with Specification D6662 using Practice G154 or D2565.
thedecreaseexceeds10%,thedeckboardspan(orloadrating)
4.6.1 Whentestingequipmentdoesnotalloweitherfull-size
shall be reduced by the amount in excess of 10%. For guards
or full-thickness test specimens, coupon specimens removed
orhandrails,ifthedecreaseexceeds10%,thetestloadsforthe
from the surface of the full-size cross section shall be used.
guards or handrails shall be increased by the amount in excess
However, when using data generated from coupon specimens,
of 10% (see X1.3).
the user must justify the estimation of the impact on the
4.8 Biodeterioration Tests—Termite and decay testing shall
full-size product (see X1.2).
be required for deck board, guard, and handrail products
4.6.2 Aminimumoffive(5)exposedandfive(5)unexposed
containing wood, cellulosic, or other biodegradable materials.
test specimens shall be tested in accordance with 4.4. The
4.8.1 Fungal Decay Resistance Test—Resistance to fungal
surface expected to receive UV exposure in service shall be
decay shall be determined in accordance with Test Methods
exposed to the UV light source. The flexure test shall be
D2017, D1413, or AWPA Standard E10.
conducted with the exposed surface in tension. If more than
4.8.1.1 Criteria—Examination of test blocks shall reveal
one component is being evaluated (for example, deck boards
decay resistance equivalent to that of preservative-treated or
and guard rail components) and all materials are manufactured
the heartwood of naturally durable wood used in identical
from the same materials, then UV testing of only one compo-
applications, as measured by visual inspection, and average
nent is required.
weight loss.
4.6.3 Acceptance Criteria—The average change in proper-
NOTE 5—This is an accelerated laboratory decay test. Results are
ties between the exposed and unexposed specimens shall be
subjective and comparisons between tests and materials should be used
calculatedasapercentageandreported.Theaveragechangein
withcaution.However,meanspecimenweightlossesgreaterthan5%,or
flexural strength and stiffness properties shall be calculated by
significantly greater than controls, should be cause for concern.
determiningthedifferencebetweenthecontrolandconditioned
4.8.2 Termites—Test Method D3345 orAWPAStandard E1
values and dividing that difference by the control value.
shall be used for evaluation of resistance to termite attack.
Condition of acceptance is the average flexural strength of
4.8.2.1 Criteria—Visual inspection of the test specimens
exposedtestspecimensandshallbewithin10%oftheaverage
shalldemonstrateresistancetotermiteattackequivalenttothat
flexural strength of unexposed specimens. For deck boards, if
of preservative-treated or the heartwood of naturally durable
thedecreaseexceeds10%,thedeckboardspan(orloadrating)
wood used in identical applications.
shall be reduced by the amount in excess of 10%. For guards
orhandrails,ifthedecreaseexceeds10%,thetestloadsforthe 4.9 Surface Burning Characteristics—The flame-spread in-
guards or handrails shall be increased by the amount in excess dex of materials used to fabricate deck boards, guards, and
of 10% (see X1.3). handrails shall be determined by testing in accordance with
Test Method E84.
4.7 Freeze-Thaw Resistance Test—To determine the me-
4.9.1 Criterion—Materials shall have a flame-spread index
chanical property degrade after freeze-thaw exposure, a mini-
no greater than 200 when tested in accordance with Test
mum of five (5) specimens shall be subjected to the following
Method E84.
exposure cycle. Whenever possible the test specimens shall be
prepared using the full cross section of the as-manufactured
5. Deck Board Performance Requirements
product.Test specimens shall be submerged underwater (using
weights to hold them down, if necessary) for a period of 24 h. 5.1 General—Deckboardsareastructuralelementandshall
The specimens shall then be placed in a freezer at −20 6 4°F be tested in flexure to establish a deck board span rating.
(−29 6 2°C) for 24 h. After being subjected to freezing, the Because deck board products are often subject to a variety of
specimensshallbereturnedtoroomtemperatureforaperiodof outdoor environments, the effect of moisture and temperature
24 h. This process comprises one hygrothermal cycle. The shall be determined and used in the determination of the span
above procedure shall be repeated two more times, for a total (or load) rating. In addition to the structural assessments,
of three cycles of water submersion, freezing, and thawing. several other performance measures shall be evaluated, which
D7032 − 21
based on engineering mechanics for a continuous beam over two spans,
include tests to determine creep-recovery (5.4), mechanical
where the support conditions are assumed to be pinned connections.
fastener capacity (5.5), and slip resistance (5.6).
Therefore, for these increases to apply, the actual installation of the stair
5.1.1 The unadjusted load derived in 5.3.1 shall be reduced
tread should be such that the deck board remains in contact with its
by the adjustment factors derived in 4.5, 4.6, and 4.7.
supports throughout its intended lifetime.
5.1.2 The test loads specified in 5.3.2 shall be increased by
5.4 Creep-Recovery Test—A minimum of three (3) speci-
the end-use adjustment factors derived in 4.5, 4.6, and 4.7.
mens representative of the population being sampled shall be
When the adjustment factors from 4.5 are required, the
loaded in flexure in accordance with 4.4 to twice the design
adjustmentfactorforMOR(ormomentcapacity)shallbeused
load for which approval is desired. Prior to loading, the test
forstrengthcriteria,andtheadjustmentfactorforMOE(orEI)
specimens shall be allowed to equilibrate to the test tempera-
shall be used for deflection criteria.
ture conditions (for example, 68 6 4°F (20 6 2 °C)) and be
5.2 Flexural Performance Tests—Flexural strength can be
maintained throughout the experiment. The load is applied for
recorded as either modulus of rupture ( MOR) or moment
24 h and the specimens are then allowed to recover with no
capacity. Flexural stiffness can be recorded either as apparent
superimposed load for 24 h. Deflection at mid-span is mea-
modulus of elasticity (MOE) or flexural stiffness (EI).
sured a minimum of four times: (1) prior to the application of
5.2.1 Flexural tests to failure at the span desired shall be
load, (2) at 24 h with load on, (3) immediately after the load is
conducted in accordance with 4.4. Sample size shall be a
removed, and (4) after the 24-h recovery period. Total deflec-
minimumof28specimensrepresentativeofnormalproduction
tionisthedeflectionthatoccursbetweentimezeroandtheend
andbeoftheactualcross-sectionsizefortheintendedenduse.
of the first 24-h loading period.The recovered deflection is the
Whenastairtreadperformanceratingisdesired,acenter-point
deflectionattheendofthe24-hrecoveryperiodminusthetotal
load test shall be also performed.
deflection.Thepercentrecoveryforeachtestspecimenshallbe
defined as the recovered deflection divided by the total
NOTE 6—Multiple-supportconditionsmaybeusedfortheflexuraltests
deflectiontimes100.Theaveragepercentrecovery,roundedto
(for example, two-span continuous).
th the nearest percent, shall be 75% or greater and reported. For
5.2.2 Themaximumload,theloadatthedeflectionat ⁄180
products where the total deflection is less than ⁄8 in. (3.2 mm),
of the test span, and a description of the failure mode for each
the unrecovered deflection shall be less than ⁄16 in. (1.6 mm).
test specimen shall be recorded. The average flexural strength
and average apparent stiffness shall be calculated and reported
5.5 Mechanical Fastener Holding Tests—Conditioning of
in accordance with 4.4. the deck boards prior to test specimen preparation shall be
conducted in accordance with 4.3. Testing of a minimum of
NOTE7—Whendeterminingthedesiredspan,itisimportanttoconsider
five (5) test specimens with each fastener and load direction
whether the boards will be installed perpendicular to or at an angle to the
that the connection must resist, such as lateral, withdrawal, or
supports (joists).
pull-through, when used to fasten deck boards to the support-
5.3 Determination of the Unadjusted Allowable Load:
ing structure, shall be conducted according to Test Methods
5.3.1 The unadjusted allowable load for the test span
D1761 or D1037 with nails, screws, or staples, and in accor-
selectedshallbecalculatedfromthelesserofthefollowing:(1)
dance with Test Method D5764 for bolts. Connections using
the average ultimate flexural strength (from 4.4) divided by a
proprietary fasteners, which include hidden fastener systems,
factorofsafetyof2.5,and (2)theaverageflexuralstrengththat
shall be tested in accordance with Test Methods D1761,
th
results in a deflection of ⁄180 of the test span.
D5764, D1037, or any other test procedure approved by the
5.3.2 Additionally, when deck boards are to be recognized
specifying authority that is appropriate for determining the
as stair treads, the boards shall also sustain a minimum
allowable capacity of the connection.The allowable capaciti
...

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: D7032 − 17 D7032 − 21
Standard Specification for
Establishing Performance Ratings for Wood-Plastic
Composite and Plastic Lumber Deck Boards, Stair Treads,
Guards, and Handrails
This standard is issued under the fixed designation D7032; 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 specification covers procedures to establish a performance rating for wood-plastic composite and plastic lumber for use
as exterior deck boards, stair treads, guards, and handrails. The purpose of this specification is to establish a basis for code
recognition of these products or systems in exterior applications. The products addressed in this specification are considered
combustible.
NOTE 1—While wood-plastic composites contain wood or other cellulosic materials, the presence of wood or other cellulosic materials in plastic lumber
is not required by this specification. Due to non-wood materials in wood-plastic composites and plastic lumber the structural, physical, fire, and other
attributes may not be similar to those of wood.
NOTE 2—The products addressed in this standard are considered combustible. No fire response characteristic is required in this specification except for
flame spread index as determined in accordance with Test Method E84.
1.1.1 The plastic component of wood-plastic composites and plastic lumber covered by this specification shall consist primarily
of thermoplastics.
1.2 Deck boards, stair treads, guards, and handrails covered by this specification are permitted to be of any code compliant shape
and thickness (solid or non-solid).
1.3 Wood-plastic composites and plastic lumber are produced in a broad range of fiber and/or resin formulations. It is recognized
that the performance requirements in this specification are valid for any material or combination of materials used as deck boards,
stair treads, guards, or handrails.
1.4 Details of manufacturing processes are beyond the scope of this specification.
1.5 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.
1.6 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory requirementslimitations prior to use.
This specification is under the jurisdiction of ASTM Committee D07 on Wood and is the direct responsibility of Subcommittee D07.02 on Lumber and Engineered Wood
Products.
Current edition approved March 1, 2017Nov. 1, 2021. Published April 2017December 2021. Originally approved in 2004. Last previous edition approved in 20152017
as D7032 – 15.D7032 – 17. DOI: 10.1520/D7032-17.10.1520/D7032-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7032 − 21
1.7 Table of Contents:
Section
Scope 1
Referenced Documents 2
Terminology 3
General Requirements 4
Sampling 4.1
Sample Size 4.2
Conditioning 4.3
Flexural Tests 4.4
Temperature and Moisture Effects 4.5
Ultraviolet (UV) Resistance Test 4.6
Freeze-Thaw Resistance Test 4.7
Biodeterioration Tests 4.8
Fire Performance Tests 4.9
Deck Board Performance Requirements 5
General 5.1
Flexural Performance Tests 5.2
Determination of the Unadjusted Allowable 5.3
Load
Creep-Recovery Test 5.4
Mechanical Fastener Holding Tests 5.5
Slip Resistance Test 5.6
Guard and Handrail Performance 6
Requirements
General 6.1
Guardrail System Test Requirements 6.2
One- and Two-Family Dwelling 6.2.1.1
Requirements
Handrail Test Requirements (Concentrated 6.3
Load)
Report 7
Independent Inspection 8
Manufacturing Standard 9
Precision and Bias 10
Keywords 11
Two-Span Test Method Annex A1
Commentary Appendix X1
1.8 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.
2. Referenced Documents
2.1 ASTM Standards:
D9 Terminology Relating to Wood and Wood-Based Products
D198 Test Methods of Static Tests of Lumber in Structural Sizes
D790 Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials
D883 Terminology Relating to Plastics
D1037 Test Methods for Evaluating Properties of Wood-Base Fiber and Particle Panel Materials
D1413 Test Method for Wood Preservatives by Laboratory Soil-Block Cultures (Withdrawn 2016)
D1554 Terminology Relating to Wood-Base Fiber and Particle Panel Materials
D1761 Test Methods for Mechanical Fasteners in Wood and Wood-Based Materials
D1929 Test Method for Determining Ignition Temperature of Plastics
D1972 Practice for Generic Marking of Plastic Products (Withdrawn 2014)
D2017 Test Method of Accelerated Laboratory Test of Natural Decay Resistance of Woods (Withdrawn 2014)
D2047 Test Method for Static Coefficient of Friction of Polish-Coated Flooring Surfaces as Measured by the James Machine
D2394 Test Methods for Simulated Service Testing of Wood and Wood-Based Finish Flooring
D2565 Practice for Xenon-Arc Exposure of Plastics Intended for Outdoor Applications
D2915 Practice for Sampling and Data-Analysis for Structural Wood and Wood-Based Products
D3345 Test Method for Laboratory Evaluation of Solid Wood for Resistance to Termites
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.
The last approved version of this historical standard is referenced on www.astm.org.
D7032 − 21
D4000 Classification System for Specifying Plastic Materials
D4092 Terminology for Plastics: Dynamic Mechanical Properties
D4761 Test Methods for Mechanical Properties of Lumber and Wood-Based Structural Materials
D5764 Test Method for Evaluating Dowel-Bearing Strength of Wood and Wood-Based Products
D6109 Test Methods for Flexural Properties of Unreinforced and Reinforced Plastic Lumber and Related Products
D6662 Specification for Polyolefin-Based Plastic Lumber Decking Boards
E84 Test Method for Surface Burning Characteristics of Building Materials
E108 Test Methods for Fire Tests of Roof Coverings
E1354 Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen Consumption
Calorimeter
F1679 Test Method for Using a Variable Incidence Tribometer (VIT) (Withdrawn 2006)
G154 Practice for Operating Fluorescent Ultraviolet (UV) Lamp Apparatus for Exposure of Nonmetallic Materials
2.2 Other References:
AWPA Standard E1 Standard Method for Laboratory Evaluation for Determination of Resistance to Subterranean Termites
AWPA Standard E10 Standard Method of Testing Wood Preservatives by Laboratory Soil-Block Cultures
2009 International Building Code International Code Council, Inc.
2009 International Residential Code International Code Council, Inc.
3. Terminology
3.1 Definitions—Terminology used to describe WPCs are defined in Terminologies D9, D883, D1554, and D4092, Practice D1972,
and Classification D4000.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 center-point load—a flexure test where the load comes in contact with the test specimen at a location that is ⁄2 the test span.
3.2.2 guard—a building component or a system of building components located at or near the open sides of elevated walking
surfaces that minimizes the possibility of a fall from the walking surface to a lower level.
3.2.3 handrail—a rail intended for grasping by the hand for guidance or support.
3.2.4 plastic lumber—a manufactured product made primarily from plastic materials (filled or unfilled), typically used as a
building material, which is usually rectangular in cross-section.
3.2.5 quarter-point loading—a flexure test where the load comes in contact with the test specimen at two locations, each of which
is located at ⁄4 the span from the specimen load support.
3.2.5.1 Discussion—
For example, quarter-point loading for a test specimen on a 24-in. (610-mm) span would have two equal loads contact the test
specimen each located 6 in. in from the test specimen load support. The distance between the two points of load would be 12 in.
(305 mm).
3.2.6 span rating—an index number that identifies the test span used in all structural load testing, which is the maximum
center-to-center support spacing for the specified end use, and allowable design capacity, in pounds per square foot
2 2
(lbf/ft (kN ⁄m )), determined in accordance with this specification.
3.2.6.1 Discussion—
For example, a deck span rating of ⁄100 recognizes the deck board for installation perpendicular to the floor joists spaced a
maximum of 16 in. (406 mm) on center, and for supporting the load combinations required by the applicable code, which in this
2 2
case cannot exceed 100 lbf/ft (4.79 kN/m ).
3.2.7 third-point loading—a flexure test where the load comes in contact with the test specimen at two locations, each of which
is located at ⁄3 the span from the specimen load support.
3.2.7.1 Discussion—
Available from American Wood-Preservers’ Association (AWPA), P.O. Box 361784, Birmingham, AL 35236-1784, http://www.awpa.com.
Available from International Code Council (ICC), 5203 Leesburg Pike, Suite 600, Falls Church, VA 22041-3401, http://www.intlcode.org.
D7032 − 21
For example, third-point loading for a test specimen on a 24-in. (610-mm) span would have two equal loads contact the test
specimen each located 8 in. in from the test specimen load support. The distance between the two points of load would also be
8 in. (205 mm).
3.2.8 wood-plastic composite (WPC)—a composite made primarily from wood- or cellulose-based materials and plastic(s).
4. General Requirements
4.1 Sampling—Samples for testing shall be representative of the population being evaluated. Sampling shall be representative of
the possible variations due to changes in raw materials and process variables over time. It is essential to consider batch-to-batch
and shift-to-shift variability when sampling actual production. Test specimens shall be selected from several production runs of a
given item. Products shall be sampled at the manufacturing site by an accredited third party inspection agency or testing laboratory.
Exceptions to sampling at the manufacturing site, such as at a warehouse or distribution center, shall be documented in the test
report.
4.2 Sample Size—Selection of a sample size depends upon the property to be estimated, the actual variation in the property
occurring in the population, and the precision with which the property is to be estimated. The principles of Practice D2915 shall
be followed. The minimum sample size shall provide estimation of mean values within 5 % in accordance with 3.4.2 of Practice
D2915.
4.3 Conditioning—Prior to testing, all specimens shall be conditioned to environmental conditions appropriate for the intended end
use of the product. Alternatively, test specimens shall be conditioned for a minimum of 40 h at 68°F 6 4°F (20°C 6 2°C) and
50 6 5 % RH. If data show that product properties are not affected by extreme moisture conditions, such as submersion, the
material shall be permitted to be tested without special conditioning. When the product is to be subjected to a water soak
environment, the test specimens shall be tested within 30 min upon removal from the treatment.
4.4 Flexural Tests—Flexural strength and stiffness shall be determined in accordance with principles of Test Methods D4761 or
D6109. Alternatively, to assess compliance with performance requirements in its intended installed configuration, the deck boards
shall be tested according to the two-span method defined in Annex A1. The test specimen cross section shall be the minimum
anticipated structural size for the intended end use. The test span shall be that for which code recognition is desired. The specimens
shall be loaded at a constant strain rate of 1 % per minute (610 %). Average time to failure for each test configuration shall be
recorded (see Commentary, X1.2). A constant strain rate of 1 % per minute is achieved by using a constant rate of test machine
crosshead motion, R, (inches/minute) computed in terms of the test span, L, and the member depth, d, by the following equation:
R 5 0.00185 3L /d (1)
For members where the depth (vertical dimension) is varying along the member length, the depth (d) shall be taken as the gross
member depth at the point of maximum moment.
NOTE 3—Eq 1 is based on the maximum extreme fiber strain at midspan of a horizontally symmetric simple span member. For a product that is symmetric
about its horizontal axis, Eq 1 yields the target strain rate at both the extreme tensile and extreme compressive faces. For a product that is not symmetric
about its horizontal axis, the Eq 1 strain rate is the average of the strains at these faces. See Commentary for additional information.
NOTE 4—Some wood-plastic composites and plastic lumber exhibit exceptionally large deformations prior to failure in bending. Users are cautioned to
take particular care in test machine set-up to accommodate large deflections, both in terms of deflection-measuring devices and support conditions.
4.4.1 Flexural Strength—Modulus of rupture (MOR) or moment capacity shall be reported for each specimen. Flexural strength
shall be calculated from the maximum load achieved or the load at 3 % strain, whichever occurs first.
4.4.2 Flexural Stiffness—Apparent modulus of elasticity (MOE) or EI shall be reported for each specimen. Flexural stiffness shall
be calculated from a linear least squares fit of the stress-strain curve over the range of 10 to 40 % of ultimate stress.
4.4.3 The flexural strength and stiffness for deck board, guard, and handrail materials shall be determined in accordance with 4.4
and shall be used to establish a standard baseline performance level for comparison with future production during the required
quality control audits.
4.5 Temperature and Moisture Effects:
D7032 − 21
4.5.1 Temperature Effect—Testing shall be conducted to verify that allowable span and load ratings are applicable at a range of
temperatures expected in service. For purposes of this specification, the lower and upper temperatures shall be -20 6 4°F (-29 6
2°C) and 125 6 4°F (52 6 2°C), respectively. Flexure tests shall be conducted to failure at the desired span. A minimum of 10
specimens shall be tested at each temperature. The flexural strength and stiffness shall be determined in accordance with 4.4 and
the average change in properties between the flexural strength and stiffness of the control flexural specimens and the specimens
tested at low and high temperatures shall be calculated as a percentage and reported. The average change in flexural strength and
stiffness properties shall be calculated by determining the difference between the control and conditioned values and dividing that
difference by the control value.
4.5.2 Moisture Effect—Testing shall be conducted to verify that allowable span and load ratings are applicable at moisture
conditions expected in service. Flexure tests shall be conducted to failure at the desired span. A minimum of 10 specimens shall
be tested at moisture conditions anticipated in service (for example, high humidity, submerged). The average maximum flexural
strength and stiffness shall be determined in accordance with 4.4. The average change in properties between the control specimens
and those tested at the in-service moisture condition of interest shall be calculated as a percentage and reported. The average
change in flexural strength and stiffness properties shall be calculated by determining the difference between the control and
conditioned values and dividing that difference by the control value.
4.5.3 Criteria—The most restrictive effect (either temperature or moisture) shall be used to adjust the performance rating of deck
boards, guardrails, and handrails. For deck boards, the deck board span (or load rating) shall be reduced by the most restrictive
effect determined from 4.5.1 or 4.5.2. For guards and handrails, if the most restrictive effect exceeds 25 %, the test loads for the
guards or handrails shall be increased by the amount in excess of 25 %.
4.6 Ultraviolet (UV) Resistance Test—To determine the mechanical property degrade after UV exposure, a minimum of five (5)
full-size or full-thickness specimens shall be exposed to a minimum of 2000 h accelerated weathering in accordance with
Specification D6662 using Practice G154 or D2565.
4.6.1 When testing equipment does not allow either full-size or full-thickness test specimens, coupon specimens removed from
the surface of the full-size cross section shall be used. However, when using data generated from coupon specimens, the user must
justify the estimation of the impact on the full-size product (see X1.2).
4.6.2 A minimum of five (5) exposed and five (5) unexposed test specimens shall be tested in accordance with 4.4. The surface
expected to receive UV exposure in service shall be exposed to the UV light source. The flexure test shall be conducted with the
exposed surface in tension. If more than one component is being evaluated (for example, deck boards and guard rail components)
and all materials are manufactured from the same materials, then UV testing of only one component is required.
4.6.3 Acceptance Criteria—The average change in properties between the exposed and unexposed specimens shall be calculated
as a percentage and reported. The average change in flexural strength and stiffness properties shall be calculated by determining
the difference between the control and conditioned values and dividing that difference by the control value. Condition of
acceptance is the average flexural strength of exposed test specimens and shall be within 10 % of the average flexural strength of
unexposed specimens. For deck boards, if the decrease exceeds 10 %, the deck board span (or load rating) shall be reduced by the
amount in excess of 10 %. For guards or handrails, if the decrease exceeds 10 %, the test loads for the guards or handrails shall
be increased by the amount in excess of 10 % (see X1.3).
4.7 Freeze-Thaw Resistance Test—To determine the mechanical property degrade after freeze-thaw exposure, a minimum of five
(5) specimens shall be subjected to the following exposure cycle. Whenever possible the test specimens shall be prepared using
the full cross section of the as-manufactured product. Test specimens shall be submerged underwater (using weights to hold them
down, if necessary) for a period of 24 h. The specimens shall then be placed in a freezer at −20 6 4°F (−29 6 2°C) for 24 h. After
being subjected to freezing, the specimens shall be returned to room temperature for a period of 24 h. This process comprises one
hygrothermal cycle. The above procedure shall be repeated two more times, for a total of three cycles of water submersion,
freezing, and thawing.
4.7.1 A minimum of five (5) exposed and five (5) unexposed specimens shall be tested in accordance with 4.4. If more than one
component is being evaluated (for example, deck boards and guard rail components) and all materials are manufactured from the
same materials, then freeze-thaw testing of only one component is required.
4.7.2 Acceptance Criteria—The average change in properties between the exposed and unexposed specimens shall be calculated
as a percentage and reported. The average change in flexural strength and stiffness properties shall be calculated by determining
D7032 − 21
the difference between the control and conditioned values and dividing that difference by the control value. Condition of
acceptance is the average flexural strength of exposed test specimens and shall be within 10 % of the average flexural strength of
unexposed specimens. For deck boards, if the decrease exceeds 10 %, the deck board span (or load rating) shall be reduced by the
amount in excess of 10 %. For guards or handrails, if the decrease exceeds 10 %, the test loads for the guards or handrails shall
be increased by the amount in excess of 10 % (see X1.3).
4.8 Biodeterioration Tests—Termite and decay testing shall be required for deck board, guard, and handrail products containing
wood, cellulosic, or other biodegradable materials.
4.8.1 Fungal Decay Resistance Test—Resistance to fungal decay shall be determined in accordance with Test Methods D2017,
D1413, or AWPA Standard E10.
4.8.1.1 Criteria—Examination of test blocks shall reveal decay resistance equivalent to that of preservative-treated or the
heartwood of naturally durable wood used in identical applications, as measured by visual inspection, and average weight loss.
NOTE 5—This is an accelerated laboratory decay test. Results are subjective and comparisons between tests and materials should be used with caution.
However, mean specimen weight losses greater than 5 %, or significantly greater than controls, should be cause for concern.
4.8.2 Termites—Test Method D3345 or AWPA Standard E1 shall be used for evaluation of resistance to termite attack.
4.8.2.1 Criteria—Visual inspection of the test specimens shall demonstrate resistance to termite attack equivalent to that of
preservative-treated or the heartwood of naturally durable wood used in identical applications.
4.9 Surface Burning Characteristics—The flame-spread index of materials used to fabricate deck boards, guards, and handrails
shall be determined by testing in accordance with Test Method E84.
4.9.1 Criterion—Materials shall have a flame-spread index no greater than 200 when tested in accordance with Test Method E84.
NOTE 5—Other test procedures may be permitted for determining a flame-spread rating for the material. Depending upon material formulation, other fire
performance tests may be required. Additionally, fire performance properties other than flame spread may be important. Test Methods E1354 or D1929
may be used to provide an assessment of one or more of the following properties: smoke release rate, mass loss rate, heat release rate, ignition
temperatures, and spread of flame.
5. Deck Board Performance Requirements
5.1 General—Deck boards are a structural element and shall be tested in flexure to establish a deck board span rating. Because
deck board products are often subject to a variety of outdoor environments, the effect of moisture and temperature shall be
determined and used in the determination of the span (or load) rating. In addition to the structural assessments, several other
performance measures shall be evaluated, which include tests to determine creep-recovery (5.4), mechanical fastener capacity
(5.5), and slip resistance (5.6).
5.1.1 The unadjusted load derived in 5.3.1 shall be reduced by the adjustment factors derived in 4.5, 4.6, and 4.7.
5.1.2 The test loads specified in 5.3.2 shall be increased by the end-use adjustment factors derived in 4.5, 4.6, and 4.7. When the
adjustment factors from 4.5 are required, the adjustment factor for MOR (or moment capacity) shall be used for strength criteria,
and the adjustment factor for MOE (or EI) shall be used for deflection criteria.
5.2 Flexural Performance Tests—Flexural strength can be recorded as either modulus of rupture ( MOR) or moment capacity.
Flexural stiffness can be recorded either as apparent modulus of elasticity (MOE) or flexural stiffness (EI).
5.2.1 Flexural tests to failure at the span desired shall be conducted in accordance with 4.4. Sample size shall be a minimum of
28 specimens representative of normal production and be of the actual cross-section size for the intended end use. When a stair
tread performance rating is desired, a center-point load test shall be also performed.
NOTE 6—Multiple-support conditions may be used for the flexural tests (for example, two-span continuous).
D7032 − 21
th
5.2.2 The maximum load, the load at the deflection at ⁄180 of the test span, and a description of the failure mode for each test
specimen shall be recorded. The average flexural strength and average apparent stiffness shall be calculated and reported in
accordance with 4.4.
NOTE 7—When determining the desired span, it is important to consider whether the boards will be installed perpendicular to or at an angle to the supports
(joists).
5.3 Determination of the Unadjusted Allowable Load:
5.3.1 The unadjusted allowable load for the test span selected shall be calculated from the lesser of the following: (1) the average
ultimate flexural strength (from 4.4) divided by a factor of safety of 2.5, and (2) the average flexural strength that results in a
th
deflection of ⁄180 of the test span.
5.3.2 Additionally, when deck boards are to be recognized as stair treads, the boards shall also sustain a minimum concentrated
2 2
load of 750 lbf (3338 N) applied over a 4 6 0.08 in. (2580 6 50 mm ) area at midspan, adjacent to the edge of the deck board.
The surface area of contact for the concentrated load point shall be either circular or square. The average stair tread deflection at
300 lbf (1335 N) load shall not be greater than 0.125 in. (3.1 mm).
5.3.3 Two-Span Adjustment—When flexural testing is conducted to failure using a simple-span condition as described in Test
Methods D4761 or D6109 and the failure mode is flexural collapse or 3 % strain, two-span adjustments for flexural strength and
stiffness shall be permitted. If the user intends to take the strength increases for hollow or thin-walled products, a confirming test
using the two-span protocol is required to verify that the failure mode is not buckling or crushing at the support. For flexural
strength (MOR or moment capacity) the increase is 23 %, and for flexural stiffness (E or EI) the increase is 39 %. The strength
increase (MOR or moment capacity) is applicable to stair treads only.
NOTE 8—The increases for flexural strength and stiffness in 5.3.3 are based on engineering mechanics for a continuous beam over two spans, where the
support conditions are assumed to be pinned connections. Therefore, for these increases to apply, the actual installation of the stair tread should be such
that the deck board remains in contact with its supports throughout its intended lifetime.
5.4 Creep-Recovery Test—A minimum of three (3) specimens representative of the population being sampled shall be loaded in
flexure in accordance with 4.4 to twice the design load for which approval is desired. Prior to loading, the test specimens shall be
allowed to equilibrate to the test temperature conditions (for example, 68 6 4°F (20 6 2 °C)) and be maintained throughout the
experiment. The load is applied for 24 h and the specimens are then allowed to recover with no superimposed load for 24 h.
Deflection at mid-span is measured a minimum of four times: (1) prior to the application
...