ASTM D7147-21

Standard Specification for Testing and Establishing Allowable Loads of Joist Hangers

ABSTRACT
This specification covers a procedure for evaluating metal devices used for wood-to-wood, wood-to-concrete, wood-to-concrete masonry, and wood-to-steel joist, beam, and girder connections. It describes test methods for evaluating the capacities of joist hangers subject to vertical and torsional loading. Also, this specification provides a method of assigning allowable loads to joist hangers based on measured strength and deformation characteristics. Test specimens consisting of a length of joist supported by joist hangers attached to two headers are subjected to a vertical load by a suitable testing machine, while the vertical load and corresponding deflection of the joist are measured and recorded to provide load-slip data.
SCOPE
1.1 This specification covers a procedure for evaluating metal devices used for wood-to-wood, wood-to-concrete, wood-to-concrete masonry, and wood-to-steel connections. This method is intended for use with devices used to connect joists, beams, and girders together. These devices are commonly described as joist hangers.  
1.2 This specification describes test methods for evaluating the capacities of joist hangers subject to vertical and torsional loading.  
1.3 This specification provides a method of assigning allowable loads to joist hangers based on measured strength and deformation characteristics. Information obtained by the provisions of this specification is applicable to design when using the Allowable Stress Design method.  
1.4 Units—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.  
1.5 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.  
1.6 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.

General Information

• Status: Published
• Publication Date: 30-Jun-2021
• ICS: 91.190 - Building accessories
• Technical Committee: D07 - Wood
• Drafting Committee: D07.05 - Wood Assemblies

Relations

• Refers: ASTM C31/C31M-24a - Standard Practice for Making and Curing Concrete Test Specimens in the Field
• Effective Date: 01-Apr-2024
• Refers: ASTM F1470-24 - Standard Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
• Effective Date: 01-Jan-2024
• Refers: ASTM E8/E8M-24 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM C31/C31M-24 - Standard Practice for Making and Curing Concrete Test Specimens in the Field
• Effective Date: 01-Jan-2024
• Refers: ASTM C39/C39M-23 - Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens
• Effective Date: 01-Dec-2023
• Refers: ASTM C90-23 - Standard Specification for Loadbearing Concrete Masonry Units
• Effective Date: 01-Dec-2023
• Refers: ASTM C1314-23b - Standard Test Method for Compressive Strength of Masonry Prisms
• Effective Date: 01-Dec-2023
• Refers: ASTM D3737-18(2023)e1 - Standard Practice for Establishing Allowable Properties for Structural Glued Laminated Timber (Glulam)
• Effective Date: 01-Oct-2023
• Refers: ASTM D1761-20 - Standard Test Methods for Mechanical Fasteners in Wood and Wood-Based Materials
• Effective Date: 15-Apr-2020
• Refers: ASTM D4442-20 - Standard Test Methods for Direct Moisture Content Measurement of Wood and Wood-Based Materials
• Effective Date: 01-Mar-2020
• Refers: ASTM C270-19a - Standard Specification for Mortar for Unit Masonry
• Effective Date: 01-May-2019
• Refers: ASTM C270-19ae1 - Standard Specification for Mortar for Unit Masonry
• Effective Date: 01-May-2019
• Refers: ASTM D5055-19 - Standard Specification for Establishing and Monitoring Structural Capacities of Prefabricated Wood I-Joists
• Effective Date: 01-Mar-2019
• Refers: ASTM D1038-19 - Standard Terminology Relating to Veneer, Plywood, and Wood Structural Panels
• Effective Date: 01-Mar-2019
• Refers: ASTM C270-19 - Standard Specification for Mortar for Unit Masonry
• Effective Date: 01-Feb-2019

Overview

ASTM D7147-21 is a crucial standard developed by ASTM International that defines the specification for testing and establishing allowable loads of joist hangers. Joist hangers are metal devices commonly used to connect joists, beams, and girders in construction, ensuring stability and load transfer between wood, concrete, masonry, and steel components. This standard details comprehensive procedures for evaluating these connections, focusing on vertical and torsional loading scenarios, and provides a structured approach to assign allowable loads based on measured strength and deformation characteristics.

Key Topics

• Scope of Evaluation: Covers testing of metal devices for wood-to-wood, wood-to-concrete, wood-to-masonry, and wood-to-steel connections, typical in building construction.
• Testing Procedures: Describes standard methods for subjecting joist hanger assemblies to vertical and torsional loads, using prescriptive setups and precise measurement of load and deflection.
• Criteria for Allowable Loads: Outlines calculation methods for allowable loads, factoring in test results, strength, and deformation data, and ensuring applicability to Allowable Stress Design (ASD).
• Material Requirements: Specifies quality and properties expected of wood, steel, fasteners, and concrete/masonry used in tests for consistent and reliable results.
• Adjustment and Reporting: Details adjustment factors for moisture content, material strength deviations, and allows for substitutions and interpolation under specified conditions.

Applications

ASTM D7147-21 is widely utilized in:

• Construction Design & Engineering: Enables architects, structural engineers, and designers to specify joist hangers with tested and reliable load ratings for use in wood, concrete, masonry, and steel frameworks.
• Product Certification & Quality Assurance: Manufacturers use the standard to certify the structural integrity and performance of their joist hangers, meeting industry and regulatory requirements.
• Building Code Compliance: Supports compliance with building codes that reference ASTM standards for structural connector evaluation.
• Structural Retrofitting and Inspection: Assists inspectors and building professionals in verifying the suitability of joist hangers used in renovations or repairs, giving confidence in the load-bearing capacity of altered or existing structures.
• Material Selection and Specification: Helps procurement managers and builders select appropriate joist hangers that meet the unique needs of each project based on documented load testing.

Related Standards

To fully implement the requirements of ASTM D7147-21, several referenced and supporting standards are commonly used, including:

• ASTM D1761 - Test Methods for Mechanical Fasteners in Wood and Wood-Based Materials
• ASTM D245 - Practice for Establishing Structural Grades and Related Allowable Properties for Visually Graded Lumber
• ASTM D5456 - Specification for Evaluation of Structural Composite Lumber Products
• ASTM D2395 - Test Methods for Density and Specific Gravity of Wood and Wood-Based Materials
• ASTM E575 - Practice for Reporting Data from Structural Tests of Building Constructions, Elements, Connections, and Assemblies
• ANSI/AWC NDS - National Design Specification for Wood Construction
• AISI S100 - North American Specification for the Design of Cold-Formed Steel Structural Members
• ACI 318 - Building Code Requirements for Structural Concrete

Using ASTM D7147-21, in combination with these related standards, streamlines the process of verifying the load capacities and safety of joist hanger installations in a diverse range of construction projects.

Summary

ASTM D7147-21 ensures that joist hangers are tested and rated to meet the rigorous demands of modern construction, providing a consistent basis for structural design, quality control, and safety in wood, concrete, masonry, and steel connections. Adhering to this standard helps ensure reliable load transfer, structural integrity, and code compliance in both new and existing buildings.

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:D7147 −21
Standard Specification for
Testing and Establishing Allowable Loads of Joist Hangers
This standard is issued under the fixed designation D7147; 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 C31/C31M Practice for Making and Curing Concrete Test
Specimens in the Field
1.1 This specification covers a procedure for evaluating
C39/C39M Test Method for Compressive Strength of Cylin-
metal devices used for wood-to-wood, wood-to-concrete,
drical Concrete Specimens
wood-to-concrete masonry, and wood-to-steel connections.
C90 Specification for Loadbearing Concrete Masonry Units
This method is intended for use with devices used to connect
C270 Specification for Mortar for Unit Masonry
joists, beams, and girders together. These devices are com-
C1314 Test Method for Compressive Strength of Masonry
monly described as joist hangers.
Prisms
1.2 This specification describes test methods for evaluating
D245 Practice for Establishing Structural Grades and Re-
the capacities of joist hangers subject to vertical and torsional
lated Allowable Properties for Visually Graded Lumber
loading.
D9 Terminology Relating to Wood and Wood-Based Prod-
1.3 Thisspecificationprovidesamethodofassigningallow-
ucts
able loads to joist hangers based on measured strength and
D1038 TerminologyRelatingtoVeneer,Plywood,andWood
deformation characteristics. Information obtained by the pro-
Structural Panels
visions of this specification is applicable to design when using
D1761 Test Methods for Mechanical Fasteners in Wood and
the Allowable Stress Design method.
Wood-Based Materials
1.4 Units—The values stated in inch-pound units are to be
D2395 TestMethodsforDensityandSpecificGravity(Rela-
regarded as standard. The values given in parentheses are
tive Density) of Wood and Wood-Based Materials
mathematical conversions to SI units that are provided for
D3737 Practice for Establishing Allowable Properties for
information only and are not considered standard.
Structural Glued Laminated Timber (Glulam)
1.5 This standard does not purport to address all of the
D4442 Test Methods for Direct Moisture Content Measure-
safety concerns, if any, associated with its use. It is the
ment of Wood and Wood-Based Materials
responsibility of the user of this standard to establish appro-
D5055 Specification for Establishing and Monitoring Struc-
priate safety, health, and environmental practices and deter-
tural Capacities of Prefabricated Wood I-Joists
mine the applicability of regulatory limitations prior to use.
D5456 Specification for Evaluation of Structural Composite
1.6 This international standard was developed in accor-
Lumber Products
dance with internationally recognized principles on standard-
D7438 Practice for Field Calibration and Application of
ization established in the Decision on Principles for the
Hand-Held Moisture Meters
Development of International Standards, Guides and Recom-
E4 Practices for Force Verification of Testing Machines
mendations issued by the World Trade Organization Technical
E8/E8M Test Methods for Tension Testing of Metallic Ma-
Barriers to Trade (TBT) Committee.
terials
2. Referenced Documents
E575 Practice for Reporting Data from Structural Tests of
Building Constructions, Elements, Connections, and As-
2.1 ASTM Standards:
semblies
F606/F606M Test Methods for Determining the Mechanical
This specification is under the jurisdiction ofASTM Committee D07 on Wood
Properties of Externally and Internally Threaded
and is the direct responsibility of Subcommittee D07.05 on Wood Assemblies.
Fasteners, Washers, Direct Tension Indicators, and Rivets
Current edition approved July 1, 2021. Published August 2021. Last previous
edition approved in 2018 as D7147– 11 (2018). DOI: 10.1520/D7147-21. F1470 Practice for Fastener Sampling for Specified Me-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
chanical Properties and Performance Inspection
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
F1575 Test Method for Determining BendingYield Moment
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. of Nails
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7147−21
2.2 Other Standards: 5. Summary of Test Method
AWC NDS National Design Specification for Wood Con-
5.1 Vertical Load Test—Test specimens consisting of a
struction
length of joist supported by joist hangers attached to two
AISI S100 North American Specification for the Design of
headers are subjected to a vertical load by a suitable testing
Cold-Formed Steel Structural Members
machine (see Figs. 1-3), while the vertical load and corre-
ANSI/AISC 360 Specification for Structural Steel Build-
sponding deflection of the joist are measured and recorded to
ings
provide load-slip data.
ANSI/ASME B18.2.1 Square, Hex, Heavy Hex, and Askew
5.1.1 Loads applied vertically downward with reference to
Head Bolts and Hex, Heavy Hex, Hex Flange, Lobed
the intended application of the joist hanger, shall be classified
Head, and Lag Screws (Inch Series)
as downward (see Fig. 1).
ACI 318/318R Building Code Requirements for Structural
5.1.2 Loads applied vertically upward with reference to the
Concrete and Commentary
intended application of the joist hanger, shall be classified as
uplift (see Fig. 2).
3. Terminology
5.2 Torsional Moment Test (optional)—A test method is
3.1 The following section defines terms used in this speci-
provided in Appendix X1 for torsional moment capacity
fication. See Terminology D9 and D1038 for other terminol-
evaluation of hangers. This test consists of a joist supported by
ogy.
two joist hangers attached to headers (see Figs. X1.1 and
3.2 Definitions:
X1.2).The movement of the joist with respect to the headers is
3.2.1 header—a member supporting a joist hanger.Aheader
measured and recorded to provide data for calculating angular
may also be referred to as a “supporting” member.
rotation and load-deflection relationships.
3.2.2 joist—a bending member supported by a joist hanger.
6. Apparatus
A joist may also be referred to as a “supported” member.
6.1 Testing Machine—A testing machine that is capable of
3.2.3 joist hanger—a metal device, usually cold-formed
operationataconstantrateofmotionofthemovablecrosshead
from light-gage steel sheet or welded from steel plate, used to
or a constant rate of loading and a force-measuring device that
transfer loads from a joist to a header member or wall in
is calibrated in accordance with Practices E4.
building construction. Face-mount joist hangers contact the
side surface of the header and do not contact the top of the
6.2 Displacement Gage—All tests shall use a dial gage(s),
header. Top-mount hangers are joist hangers that contact the
or equivalent, to measure the relative movement between the
side and top surface of the header.
joist and header. Devices used for this purpose shall have a
3.2.4 sawn lumber—see definition for lumber in Terminol- least reading of 0.001 in. (0.02 mm).
ogy D9.
7. Test Materials
3.2.5 structural composite lumber (SCL)—see Specification
7.1 Wood—All wood materials shall be of structural quality
D5456.
with allowable values substantiated by accepted procedures,
3.2.6 structural glued laminated timber (glulam)—see Prac-
such as those found in Section 2. The specific gravity of the
tice D3737.
joists and headers shall be determined in accordance with Test
3.2.7 wood I-joists—see Specification D5055.
Methods D2395, and moisture content of the joists and headers
shallbedeterminedinaccordancewithTestMethodsD4442or
4. Significance and Use
Practice D7438. All specific gravities shall be reported on an
4.1 Joist hangers are used to transfer vertical loads from a
joist to a header in building construction. In addition to vertical
load transfer, joist hangers may provide torsional resistance for
the ends of a joist. The performance of this connection is
influenced by a number of variables, such as the properties of
the hanger, the joist material, the header material, and the
fasteners. The test described in this specification provide for
consistency in evaluating the performance of such assembled
units.
Available fromAmerican Wood Council (AWC), 222 Catoctin Circle SE, Suite
201, Leesburg, VA 20175.
Available from American Iron and Steel Institute (AISI), 1101 17th St., NW,
Suite 1300, Washington, DC 20036.
Available from American Institute of Steel Construction (AISC), One E.
Wacker Dr., Suite 3100, Chicago, IL 60601-2001.
Available from American Society of Mechanical Engineers (ASME), ASME
International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
Available from American Concrete Institute (ACI), 38800 Country Club Dr.,
Farmington Hills, MI 48331-3439, http://www.concrete.org. FIG. 1Typical Vertical Downward Test Setup
D7147−21
NOTE 1—It is not uncommon for SCL manufacturers to conservatively
assign a design value for fastener performance for a product type (that is,
parallel strand lumber, laminated veneer lumber, laminated strand lumber,
etc.) that covers multiple species, process variables, and grades. Sampling
SCL materials and components made thereof (that is, I-joist flange
materials) from the species and grade mix that conservatively addresses
the range for a given product type is one way to satisfy this requirement.
8.2 A minimum of three identical tests shall be performed
for each selected hanger condition.
9. Test Setup
9.1 Ajoisthangertestsetupshallconsistofajoistsupported
between two headers by the hanger devices to be evaluated.
9.2 Headers shall have a length sufficient to provide the
intended hanger-to-header contact for the hanger, for example,
space for nailing and bearing as applicable. The minimum
header length shall be 18 in. (457 mm). See Fig. 3.
FIG. 2Typical Uplift Test Setup
9.3 Joist length shall be in accordance with Fig. 3.
9.3.1 Joist lengths shall be sufficient to prevent contact
between joist hangers and any material other than the attached
oven-dry basis in accordance with Test Methods D2395.
headers and joist.Aminimum horizontal clear distance of 3 in.
Specificgravitymeasurementstakenatmoisturecontentsother
(76 mm) or ⁄3 the joist depth, whichever is smaller, shall be
than oven-dry shall be adjusted to the oven-dry moisture
provided between the load transfer block and the hanger seat.
content in accordance with Appendix X1 of Test Methods
Aminimum clearance of 0.125 in. (3.18 mm) shall be provided
D2395.
between each end of the joist and abutting material, such as the
7.2 Concrete or Masonry:
adjacent header or any hanger section between the header and
7.2.1 If concrete is used, a minimum of two concrete test
the joist (see Fig. 4). Prior to loading, the 0.125 in. (3.18 mm)
cylinders shall be prepared, stored, and cured in accordance
gap shall be maintained between joist and header by providing
with Practice C31/C31M from the same batch of concrete used
blocking, or equivalent, between the ends of the headers.
in the joist hanger test specimen. Cylinders shall be tested in
9.3.2 To minimize header-joist load transfer due to friction,
accordance with Test Method C39/C39M within 24 h of the
a low friction material with a thickness no greater than 0.063
test of the joist hanger.
in. (1.6 mm) shall be inserted into the 0.125 in. (3.18 mm) gap
7.2.2 If masonry is used, the compressive strength of the
prior to loading.
masonry shall be determined by the prism test method in
9.3.3 The seat of the hanger shall be prevented from direct
accordance with Test Method C1314.
contact with the header during the test unless provisions are
made to prevent the hanger seat from gouging into the header
7.3 Steel—Standard tensile tests of the steel from which the
orthehangerseatshallbeatorbelowthebottomoftheheader.
joist hanger was produced shall be conducted in accordance
with Test Methods E8/E8M.
9.4 Header Supports:
9.4.1 Header supports shall provide sufficient bearing to
7.4 Fasteners—Fasteners from the same manufacturer’s lot
prevent excessive crushing.
as were used in the joist hanger test specimen shall be sampled
9.4.2 No portion of the joist hanger shall bear on any
in accordance with Practice F1470 to determine the fastener
support other than the header during the test. This shall be
bending yield strength. Nails and wood screws shall be tested
accomplished by:
for bending yield strength in accordance with Test Method
9.4.2.1 Using raised supports with a minimum header over-
F1575. Bolts shall be tested in accordance with Test Methods
hang of ⁄8 in. (3.18 mm) at the inside edges (see Figs. 1-3), or
F606/F606M for the properties relevant to the application.
9.4.2.2 Using headers that are deeper than the joist by an
8. Sampling amount sufficient to ensure that neither the joist nor the hanger
contact the test bed.
8.1 Sampling shall provide for selection of representative
9.4.3 The test bed or any header supports shall not contact
testmaterialsexceptwherethetestsaredesignedtospecifically
the joist or joist hanger at any time during the test.
address use with particular grades, dimensions, wood species,
or other condition. Properties of tested materials shall be
NOTE 2—A ⁄8-in. (3.18 mm) overhang of the header beyond the inside
edge of the support has historically been provided to ensure contact does
permitted to exceed the minimum or nominal values of those
not occur between the joist hanger and the header support.
properties reported in relevant specifications for that material
provided the adjustments to tested results that are addressed in 9.5 Reinforcement of joist members at the area of load
Section 13 are made. Structural composite lumber and I-joist application shall be permitted to prevent member failure in
materials shall be chosen to represent the grade and species of bending, shear, or compression perpendicular-to-grain at the
each product type that conservatively represent the range of applied load, so as to produce: (1) a failure in the joist hanger,
similar products to be addressed by each test set. (2) a failure of the fasteners between the joist hanger and the
D7147−21
FIG. 3Vertical Downward Test Setup
FIG. 4Required Gap When Portion of Joist Hanger Exists Between Header and Joist
joist, (3) a failure of the fasteners between the joist hanger and perform the essential function of testing the joist hanger
the header member(s), or (4) a joist bearing failure at the device, and provided that such departures are reported in the
hanger. The length of joist reinforcement shall be no closer test report in detail.
than 2 in. (51 mm) from the end of each hanger.
10. Conditioning
9.6 Blocking between the headers or alternate methods shall
be provided to prevent rotation of the headers inward towards 10.1 Test specimens fabricated and tested with dimension
the joist. Tensile reinforcement between the headers shall be lumber shall have a moisture content of not less than 11 %
permittedtopreventrotationoftheheadersoutwardawayfrom unless adjustments are made to test results in accordance with
the joist. Such reinforcement shall not contact the joist hangers 13.2.
or otherwise interfere with their performance.
10.2 For structural composite lumber, structural glued-
9.7 Where a hanger device is of a design that is not laminated wood and wood I-joist products, tests shall be made
adaptable to the test setup described above, necessary depar- at a moisture content of no less than 7 %. When the member
tures shall be permitted, provided the altered setup will consists of different elements, such as an I-joist flange, a web,
D7147−21
or other wood elements, or a combination thereof, moisture 12. Report
content shall be measured of all parts in contact with the joist
12.1 The test report shall follow the format of Practice
hanger or its fasteners.
E575, shall include a detailed drawing of the test setup, and
10.2.1 Exception—The moisture content of plywood and
shall include the following:
oriented strand board elements need not be measured.
12.1.1 A description of the joist hangers tested including a
drawing of the joist hangers showing all pertinent dimensions
11. Procedure
and material specifications, and a description of the required
fasteners,
11.1 The following properties must be determined for ma-
terials used in the test: 12.1.2 Adescription of the joist, headers, and any backer or
(1) tensile strength of hanger steel, filler blocking or stiffeners,
(2) specific gravity of wood materials as outlined in 13.5.2
12.1.2.1 Actual dimensions, species, grades, specific
– 13.5.4, and
gravities, moisture contents for each header, and joist of each
(3) bending yield strength of the fasteners.
assembly, including name of the manufacturer for proprietary
products,
11.2 Vertical movement of the joist with respect to each
12.1.2.2 Adescriptionofanymodificationsmadetothejoist
header shall be measured with a minimum of two dial gages or
or headers used in the test assembly,
other suitable device as depicted in Fig. 3. The dial gage shall
12.1.3 The measured hanger steel properties including yield
measure movement of any point along the depth of the joist
strength, ultimate strength, and base metal thickness. The base
(top, bottom, or side) located within 1.5 in. (38 mm) from the
metal thickness shall be permitted to be determined by sub-
end of the joist. Dial gage bases shall be attached to the bottom
tracting the average measured coating thickness from the
half of the header to the center of the gage base or attached to
average measured overall thickness,
the test machine bed.
12.1.4 A description of the fasteners including the finish,
11.2.1 Exception—When the joist setup is inverted for uplift
headconfiguration,headdiameter,andmarkings;themeasured
testing, the dial gage or other suitable device shall be located
length, diameter; and strength properties required in 7.4,
on the joist within 1 in. (25 mm) from the end of the hanger
seat. 12.1.5 A description of the concrete or masonry properties,
including measured properties as required in 7.2, if concrete or
11.3 The load shall be centered over the joist and be
masonry was used,
transferredfromthecrossheadtothetestspecimeninamanner
12.1.6 A description of the load transfer block, other
thatwillassureequaldistributionoftheloadtobothendsofthe
blocking, low-friction materials, reinforcement, and any devia-
joist. The load shall be applied over a sufficient joist length to
tions from the standard test setup shown in Figs. 3 and 4,
prevent excessive crushing under the loading head and shall
12.1.7 Data on load-deflection, including the load at the
conform to the requirements of Section 9.
0.125 in. (3.18 mm) deflection limit, and the maximum test
11.4 For downward load capacity tests, an initial load, or
load observed,
preload, shall be applied to the joist to seat the test assembly.
12.1.8 Type and location of failure of the specimen,
This preload shall not exceed 20 % of the ultimate load. This
12.1.9 Number of replications including a description of
load shall then be removed and the dial gages shall be set to
replications not used as allowed in 11.7,
zero. The preload shall be recorded and reported for each test
12.1.10 Loading procedure details, including preload, load
specimen.
rate, and time to maximum load, and
11.5 An initial load, or preload, shall not be applied for
12.1.11 Details of any deviations from the prescribed test
uplift load capacity tests.
setup and test procedures as outlined in this specification.
11.6 The load shall be applied at a uniform crosshead rate
13. Allowable Joist Hanger Loads Limited by Test
between 0.03 and 0.20 in. (0.8 to 5.1 mm) per minute. For all
tests, the ultimate load shall not be reached in less than 5 min.
13.1 Joist hanger design values limited by test shall be
11.6.1 The loads shall be recorded to a precision of 1 % for
limited to the materials tested, except as otherwise provided in
loads exceeding 1000 lb (4450 N) and 10 lb (44.5 N) for loads
Section 13. For application to materials used in construction,
not exceeding 1000 lb (4450 N). The deflections shall be
the construction materials shall satisfy 13.1.1 – 13.1.4.
recorded to the nearest 0.001 in. (0.02 mm). A sufficient
13.1.1 Wood—All wood materials shall be of structural
number of readings shall be taken to permit determining the
quality with allowable values substantiated by accepted
load at a deflection of 0.125 in. (3.18 mm).
procedures, such as those found in Section 2.
13.1.2 Steel—All production steel material shall meet or
11.7 Wood failure modes, such as joist bending failure and
exceed a specified minimum yield strength, a specified mini-
joist top surface crushing at the load transfer block, are
mum ultimate strength, and a specified minimum thickness.
unrelated to the performance of the joist hanger. When such
failure modes occur, it shall be permitted to replace the tests 13.1.3 Fasteners—Fasteners used for field installation shall
that resulted in these failure modes with additional tests with meet or exceed minimum specified cross-sectional dimensions
appropriate reinforcement to prevent the reoccurrence of these (for example, diameter or width and thickness), length, other
failure modes. relevant dimensions, and relevant material properties.
D7147−21
13.1.4 Concrete and Masonry—All concrete and masonry
MC = moisture content (%) in test samples.
test
materials shall have structural properties that meet or exceed a
R = adjustment factor (≤1.0) applied to test results
J
minimum specified compression strength.
when joist test materials are stronger than mate-
rials used in field applications.
13.2 Allowable loads for joist hangers based upon test shall
R = adjustment factor (≤1.0) applied to test results of
HF
be the lesser of the values determined in 13.3 and 13.4.
face mount hangers when header test materials
Adjustments to test results shall be made in accordance with
are stronger than materials used in field applica-
13.5.
tions.
13.2.1 The results of all load tests except those tests
R = adjustment factor (≤1.0) applied to test results of
HT
excludedper11.7shallbeusedtodeterminetheallowableloa
...

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: D7147 − 11 (Reapproved 2018) D7147 − 21
Standard Specification for
Testing and Establishing Allowable Loads of Joist Hangers
This standard is issued under the fixed designation D7147; 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 a procedure for evaluating metal devices used for wood-to-wood, wood-to-concrete, wood-to-
concrete masonry, and wood-to-steel connections. This method is intended for use with devices used to connect joists, beams, and
girders together. These devices are commonly described as joist hangers.
1.2 This specification describes test methods for evaluating the capacities of joist hangers subject to vertical and torsional loading.
1.3 This specification provides a method of assigning allowable loads to joist hangers based on measured strength and deformation
characteristics. Information obtained by the provisions of this specification is applicable to design when using the Allowable Stress
Design method.
1.4 Units—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.
1.5 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.
1.6 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:
C31/C31M Practice for Making and Curing Concrete Test Specimens in the Field
C39/C39M Test Method for Compressive Strength of Cylindrical Concrete Specimens
C90 Specification for Loadbearing Concrete Masonry Units
C270 Specification for Mortar for Unit Masonry
C1314 Test Method for Compressive Strength of Masonry Prisms
D245 Practice for Establishing Structural Grades and Related Allowable Properties for Visually Graded Lumber
D9 Terminology Relating to Wood and Wood-Based Products
D1038 Terminology Relating to Veneer, Plywood, and Wood Structural Panels
D1761 Test Methods for Mechanical Fasteners in Wood and Wood-Based Materials
This specification 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 Aug. 15, 2018July 1, 2021. Published November 2018August 2021. Last previous edition approved in 20112018 as D7147–11. DOI:
10.1520/D7147-11R18.– 11 (2018). DOI: 10.1520/D7147-21.
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
D7147 − 21
D2395 Test Methods for Density and Specific Gravity (Relative Density) of Wood and Wood-Based Materials
D3737 Practice for Establishing Allowable Properties for Structural Glued Laminated Timber (Glulam)
D4442 Test Methods for Direct Moisture Content Measurement of Wood and Wood-Based Materials
D5055 Specification for Establishing and Monitoring Structural Capacities of Prefabricated Wood I-Joists
D5456 Specification for Evaluation of Structural Composite Lumber Products
D7438 Practice for Field Calibration and Application of Hand-Held Moisture Meters
E4 Practices for Force Verification of Testing Machines
E8/E8M Test Methods for Tension Testing of Metallic Materials
E575 Practice for Reporting Data from Structural Tests of Building Constructions, Elements, Connections, and Assemblies
F606/F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners,
Washers, Direct Tension Indicators, and Rivets
F1470 Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection
F1575 Test Method for Determining Bending Yield Moment of Nails
2.2 Other Standards:
ANSI/AWCAWC NDS National Design Specification for Wood Construction
AISI S100 North American Specification for the Design of Cold-Formed Steel Structural Members
ANSI/AISC 360 Specification for Structural Steel Buildings
ANSI/ASME B18.2.1–2010B18.2.1 Square, Hex, Heavy Hex, and Askew Head Bolts and Hex, Heavy Hex, Hex Flange, Lobed
Head, and Lag Screws (Inch Series)
ACI 318/318R Building Code Requirements for Structural Concrete and Commentary
3. Terminology
3.1 The following section defines terms used in this specification. See Terminology D9 and D1038 for other terminology.
3.2 Definitions:
3.2.1 header—a member supporting a joist hanger. A header may also be referred to as a “supporting” member.
3.2.2 joist—a bending member supported by a joist hanger. A joist may also be referred to as a “supported” member.
3.2.3 joist hanger—a metal device, usually cold-formed from light-gage steel sheet or welded from steel plate, used to transfer
loads from a joist to a header member or wall in building construction. Face-mount joist hangers contact the side surface of the
header and do not contact the top of the header. Top-mount hangers are joist hangers that contact the side and top surface of the
header.
3.2.4 sawn lumber—see definition for lumber in Terminology D9.
3.2.5 structural composite lumber (SCL)—see Specification D5456.
3.2.6 structural glued laminated timber (glulam)—see Practice D3737.
3.2.7 wood I-joists—see Specification D5055.
4. Significance and Use
4.1 Joist hangers are used to transfer vertical loads from a joist to a header in building construction. In addition to vertical load
transfer, joist hangers may provide torsional resistance for the ends of a joist. The performance of this connection is influenced by
a number of variables, such as the properties of the hanger, the joist material, the header material, and the fasteners. The test
described in this specification provide for consistency in evaluating the performance of such assembled units.
Available from American Wood Council (AWC), 222 Catoctin Circle SE, Suite 201, Leesburg, VA 20175.
Available from American Iron and Steel Institute (AISI), 1101 17th St., NW, Suite 1300, Washington, DC 20036.
Available from American Institute of Steel Construction (AISC), One E. Wacker Dr., Suite 3100, Chicago, IL 60601-2001.
Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
Available from American Concrete Institute (ACI), 38800 Country Club Dr., Farmington Hills, MI 48331-3439, http://www.concrete.org.
D7147 − 21
5. Summary of Test Method
5.1 Vertical Load Test—Test specimens consisting of a length of joist supported by joist hangers attached to two headers are
subjected to a vertical load by a suitable testing machine (see Figs. 1-3), while the vertical load and corresponding deflection of
the joist are measured and recorded to provide load-slip data.
5.1.1 Loads applied vertically downward with reference to the intended application of the joist hanger, shall be classified as
downward (see Fig. 1).
5.1.2 Loads applied vertically upward with reference to the intended application of the joist hanger, shall be classified as uplift
(see Fig. 2).
5.2 Torsional Moment Test (optional)—A test method is provided in Appendix X1 for torsional moment capacity evaluation of
hangers. This test consists of a joist supported by two joist hangers attached to headers (see Figs. X1.1 and X1.2). The movement
of the joist with respect to the headers is measured and recorded to provide data for calculating angular rotation and load-deflection
relationships.
6. Apparatus
6.1 Testing Machine—A testing machine that is capable of operation at a constant rate of motion of the movable crosshead or a
constant rate of loading and a force-measuring device that is calibrated in accordance with Practices E4.
6.2 Displacement Gage—All tests shall use a dial gage(s), or equivalent, to measure the relative movement between the joist and
header. Devices used for this purpose shall have a least reading of 0.001 in. (0.02 mm).
7. Test Materials
7.1 Wood—All wood materials shall be of structural quality with allowable values substantiated by accepted procedures, such as
those found in Section 2. The specific gravity of the joists and headers shall be determined in accordance with Test Methods D2395,
and moisture content of the joists and headers shall be determined in accordance with Test Methods D4442 or Practice D7438. All
specific gravities shall be reported on an oven-dry basis in accordance with Test Methods D2395. Specific gravity measurements
taken at moisture contents other than oven-dry shall be adjusted to the oven-dry moisture content in accordance with Appendix
X1 of Test Methods D2395.
7.2 Concrete or Masonry:
7.2.1 If concrete is used, a minimum of two concrete test cylinders shall be prepared, stored, and cured in accordance with Practice
FIG. 1 Typical Vertical Downward Test Setup
D7147 − 21
FIG. 2 Typical Uplift Test Setup
C31/C31M from the same batch of concrete used in the joist hanger test specimen. Cylinders shall be tested in accordance with
Test Method C39/C39M within 24 h of the test of the joist hanger.
7.2.2 If masonry is used, the compressive strength of the masonry shall be determined by the prism test method in accordance with
Test Method C1314.
7.3 Steel—Standard tensile tests of the steel from which the joist hanger was produced shall be conducted in accordance with Test
Methods E8/E8M.
7.4 Fasteners—Fasteners from the same manufacturer’s lot as were used in the joist hanger test specimen shall be sampled in
accordance with Practice F1470 to determine the fastener bending yield strength. Nails and wood screws shall be tested for bending
yield strength in accordance with Test Method F1575. Bolts shall be tested in accordance with Test Methods F606/F606M for the
properties relevant to the application.
8. Sampling
8.1 Sampling shall provide for selection of representative test materials except where the tests are designed to specifically address
use with particular grades, dimensions, wood species, or other condition. Properties of tested materials shall be permitted to exceed
the minimum or nominal values of those properties reported in relevant specifications for that material provided the adjustments
to tested results that are addressed in Section 13 are made. Structural composite lumber and I-joist materials shall be chosen to
represent the grade and species of each product type that conservatively represent the range of similar products to be addressed
by each test set.
NOTE 1—It is not uncommon for SCL manufacturers to conservatively assign a design value for fastener performance for a product type (that is, parallel
strand lumber, laminated veneer lumber, laminated strand lumber, etc.) that covers multiple species, process variables, and grades. Sampling SCL
materials and components made thereof (that is, I-joist flange materials) from the species and grade mix that conservatively addresses the range for a given
product type is one way to satisfy this requirement.
8.2 A minimum of three identical tests shall be performed for each selected hanger condition.
9. Test Setup
9.1 A joist hanger test setup shall consist of a joist supported between two headers by the hanger devices to be evaluated.
9.2 Headers shall have a length sufficient to provide the intended hanger-to-header contact for the hanger, for example, space for
nailing and bearing as applicable. The minimum header length shall be 18 in. (457 mm). See Fig. 3.
9.3 Joist length shall be in accordance with Fig. 3.
D7147 − 21
FIG. 3 Vertical Downward Test Setup
9.3.1 Joist lengths shall be sufficient to prevent contact between joist hangers and any material other than the attached headers and
joist. A minimum horizontal clear distance of 3 in. (76 mm) or ⁄3 the joist depth, whichever is smaller, shall be provided between
the load transfer block and the hanger seat. A minimum clearance of 0.125 in. (3.18 mm) shall be provided between each end of
the joist and abutting material, such as the adjacent header or any hanger section between the header and the joist (see Fig. 4). Prior
to loading, the 0.125 in. (3.18 mm) gap shall be maintained between joist and header by providing blocking, or equivalent, between
the ends of the headers.
9.3.2 To minimize header-joist load transfer due to friction, a low friction material with a thickness no greater than 0.063 in. (1.6
mm) shall be inserted into the 0.125 in. (3.18 mm) gap prior to loading.
9.3.3 The seat of the hanger shall be prevented from direct contact with the header during the test unless provisions are made to
prevent the hanger seat from gouging into the header or the hanger seat shall be at or below the bottom of the header.
9.4 Header Supports:
FIG. 4 Required Gap When Portion of Joist Hanger Exists Between Header and Joist
D7147 − 21
9.4.1 Header supports shall provide sufficient bearing to prevent excessive crushing.
9.4.2 No portion of the joist hanger shall bear on any support other than the header during the test. This shall be accomplished
by:
9.4.2.1 Using raised supports with a minimum header overhang of ⁄8 in. (3.18 mm) at the inside edges (see Figs. 1-3), or
9.4.2.2 Using headers that are deeper than the joist by an amount sufficient to ensure that neither the joist nor the hanger contact
the test bed.
9.4.3 The test bed or any header supports shall not contact the joist or joist hanger at any time during the test.
NOTE 2—A ⁄8-in. (3.18 mm) overhang of the header beyond the inside edge of the support has historically been provided to ensure contact does not occur
between the joist hanger and the header support.
9.5 Reinforcement of joist members at the area of load application shall be permitted to prevent member failure in bending, shear,
or compression perpendicular-to-grain at the applied load, so as to produce: (1) a failure in the joist hanger, (2) a failure of the
fasteners between the joist hanger and the joist, (3) a failure of the fasteners between the joist hanger and the header member(s),
or (4) a joist bearing failure at the hanger. The length of joist reinforcement shall be no closer than 2 in. (51 mm) from the end
of each hanger.
9.6 Blocking between the headers or alternate methods shall be provided to prevent rotation of the headers inward towards the
joist. Tensile reinforcement between the headers shall be permitted to prevent rotation of the headers outward away from the joist.
Such reinforcement shall not contact the joist hangers or otherwise interfere with their performance.
9.7 Where a hanger device is of a design that is not adaptable to the test setup described above, necessary departures shall be
permitted, provided the altered setup will perform the essential function of testing the joist hanger device, and provided that such
departures are reported in the test report in detail.
10. Conditioning
10.1 Test specimens fabricated and tested with dimension lumber shall have a moisture content of not less than 11 % unless
adjustments are made to test results in accordance with 13.2.
10.2 For structural composite lumber, structural glued-laminated wood and wood I-joist products, tests shall be made at a moisture
content of no less than 7 %. When the member consists of different elements, such as an I-joist flange, a web, or other wood
elements, or a combination thereof, moisture content shall be measured of all parts in contact with the joist hanger or its fasteners.
10.2.1 Exception—The moisture content of plywood and oriented strand board elements need not be measured.
11. Procedure
11.1 The following properties must be determined for materials used in the test:
(1) tensile strength of hanger steel,
(2) specific gravity of wood materials as outlined in 13.5.2 – 13.5.4, and
(3) bending yield strength of the fasteners.
11.2 Vertical movement of the joist with respect to each header shall be measured with a minimum of two dial gages or other
suitable device as depicted in Fig. 3. The dial gage shall measure movement of any point along the depth of the joist (top, bottom,
or side) located within 1.5 in. (38 mm) from the end of the joist. Dial gage bases shall be attached to the bottom half of the header
to the center of the gage base or attached to the test machine bed.
11.2.1 Exception—When the joist setup is inverted for uplift testing, the dial gage or other suitable device shall be located on the
joist within 1 in. (25 mm) from the end of the hanger seat.
D7147 − 21
11.3 The load shall be centered over the joist and be transferred from the crosshead to the test specimen in a manner that will
assure equal distribution of the load to both ends of the joist. The load shall be applied over a sufficient joist length to prevent
excessive crushing under the loading head and shall conform to the requirements of Section 9.
11.4 For downward load capacity tests, an initial load, or preload, shall be applied to the joist to seat the test assembly. This preload
shall not exceed 20 % of the ultimate load. This load shall then be removed and the dial gages shall be set to zero. The preload
shall be recorded and reported for each test specimen.
11.5 An initial load, or preload, shall not be applied for uplift load capacity tests.
11.6 The load shall be applied at a uniform crosshead rate between 0.03 and 0.20 in. (0.8 to 5.1 mm) per minute. For all tests,
the ultimate load shall not be reached in less than 5 min.
11.6.1 The loads shall be recorded to a precision of 1 % for loads exceeding 1000 lb (4450 N) and 10 lb (44.5 N) for loads not
exceeding 1000 lb (4450 N). The deflections shall be recorded to the nearest 0.001 in. (0.02 mm). A sufficient number of readings
shall be taken to permit determining the load at a deflection of 0.125 in. (3.18 mm).
11.7 Wood failure modes, such as joist bending failure and joist top surface crushing at the load transfer block, are unrelated to
the performance of the joist hanger. When such failure modes occur, it shall be permitted to replace the tests that resulted in these
failure modes with additional tests with appropriate reinforcement to prevent the reoccurrence of these failure modes.
12. Report
12.1 The test report shall follow the format of Practice E575, shall include a detailed drawing of the test setup, and shall include
the following:
12.1.1 A description of the joist hangers tested including a drawing of the joist hangers showing all pertinent dimensions and
material specifications, and a description of the required fasteners,
12.1.2 A description of the joist, headers, and any backer or filler blocking or stiffeners,
12.1.2.1 Actual dimensions, species, grades, specific gravities, moisture contents for each header, and joist of each assembly,
including name of the manufacturer for proprietary products,
12.1.2.2 A description of any modifications made to the joist or headers used in the test assembly,
12.1.3 The measured hanger steel properties including yield strength, ultimate strength, and base metal thickness. The base metal
thickness shall be permitted to be determined by subtracting the average measured coating thickness from the average measured
overall thickness,
12.1.4 A description of the fasteners including the finish, head configuration, head diameter, and markings; the measured length,
diameter; and strength properties required in 7.4,
12.1.5 A description of the concrete or masonry properties, including measured properties as required in 7.2, if concrete or
masonry was used,
12.1.6 A description of the load transfer block, other blocking, low-friction materials, reinforcement, and any deviations from the
standard test setup shown in Figs. 3 and 4,
12.1.7 Data on load-deflection, including the load at the 0.125 in. (3.18 mm) deflection limit, and the maximum test load observed,
12.1.8 Type and location of failure of the specimen,
12.1.9 Number of replications including a description of replications not used as allowed in 11.7,
12.1.10 Loading procedure details, including preload, load rate, and time to maximum load, and
D7147 − 21
12.1.11 Details of any deviations from the prescribed test setup and test procedures as outlined in this specification.
13. Allowable Joist Hanger Loads Limited by Test
13.1 Joist hanger design values limited by test shall be limited to the materials tested, except as otherwise provided in Section 13.
For application to materials used in construction, the construction materials shall satisfy 13.1.1 – 13.1.4.
13.1.1 Wood—All wood materials shall be of structural quality with allowable values substantiated by accepted procedures, such
as those found in Section 2.
13.1.2 Steel—All production steel material shall meet or exceed a specified minimum yield strength, a specified minimum ultimate
strength, and a specified minimum thickness.
13.1.3 Fasteners—Fasteners used for field installation shall meet or exceed minimum specified cross-sectional dimensions (for
example, diameter or width and thickness), length, other relevant dimensions, and relevant material properties.
13.1.4 Concrete and Masonry—All concrete and masonry materials shall have structural properties that meet or exceed a
minimum specified compression strength.
13.2 Allowable loads for joist hangers based upon test shall be the lesser of the values determined in 13.3 and 13.4. Adjustments
to test results shall be made in accordance with 13.5.
13.2.1 The results of all load tests except those tests excluded per 11.7 shall be used to determine the allowable load capacity of
the joist hanger.
13.3 Test Strength Limit:
13.3.1 The ultimate load rating shall be the lowest ultimate load per joist hanger divided by 3.0 if less than six replicates are tested.
The ultimate load rating shall be the average ultimate load per joist hanger divided by 3.0 when six or more replicates are tested.
See 13.5 for adjustments to test results.
13.4 Test Deflection Limit:
13.4.1 For all vertical load tests, the load at 0.125-in. (3.18 mm) deflection shall be recorded for each hanger. The test deflection
limit load shall be the average of all of these loads. The load at the specified deflection limit shall be permitted to be interpolated
from the test data.
13.5 Adjustments to Test Strength Limit:
13.5.1 The resulting test values shall be multiplied by the lowest of the adjustment factors determined in 13.5.2 – 13.5.4.
NOTE 3—The adjustments outlin
...