ASTM C645-18

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Designation: C645 − 14 C645 − 18
Standard Specification for
Nonstructural Steel Framing Members
This standard is issued under the fixed designation C645; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—Fig. 2 was revised editorially to remove an unnecessary asterisk in Dec. 2015.
1. Scope*
1.1 This specification covers nonstructural steel framing members in interior construction assemblies.
1.2 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.
1.3 The following safety hazards caveat pertains only to the test methods portion, Sections 9 and 10, of this specification: 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 limitations prior to use.
1.4 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:
A653/A653M Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the
Hot-Dip Process
A1003/A1003M Specification for Steel Sheet, Carbon, Metallic- and Nonmetallic-Coated for Cold-Formed Framing Members
C11 Terminology Relating to Gypsum and Related Building Materials and Systems
C475/C475M Specification for Joint Compound and Joint Tape for Finishing Gypsum Board
C754 Specification for Installation of Steel Framing Members to Receive Screw-Attached Gypsum Panel Products
C1002 Specification for Steel Self-Piercing Tapping Screws for Application of Gypsum Panel Products or Metal Plaster Bases
to Wood Studs or Steel Studs
C1396/C1396M Specification for Gypsum Board
2.2 AISI Standards:
S100 North American Specification for the Design of Cold-Formed Steel Structural Members, 2007 edition
S220 North American Standard for Cold-Formed Steel Framing—Nonstructural Members, 20112015 Edition
2.3 ICC-ES Document
ICC-ES-AC86 Acceptance Criteria for Cold-formed Steel Framing Members—Interior Nonload-bearing Wall Assemblies—
Approved May 2012
3. Terminology
3.1 Definitions—Definitions shall be in accordance with Terminology C11.
3.2 Definitions of Terms Specific to This Standard:
This specification is under the jurisdiction of ASTM Committee C11 on Gypsum and Related Building Materials and Systems and is the direct responsibility of
Subcommittee C11.02 on Specifications and Test Methods for Accessories and Related Products.
Current edition approved Nov. 1, 2014June 1, 2018. Published November 2014June 2018. Originally approved in 1970. Last previous edition approved in 20132014 as
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C645 – 13.C645 – 14 . DOI: 10.1520/C0645-14E01.10.1520/C0645-18.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American Iron and Steel Institute (AISI), 1140 Connecticut Ave., NW, Suite 705, Washington, DC 20036, http://www.steel.org.
Available from ICC Evaluation Services, Inc., 5360 Workman Mill Road, Whittier, CA 90601, www.icc-es.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C645 − 18
3.2.1 members, n—in screw application of gypsum board, studs, runners (track), hat furring channels, main beams, and cross
furring members of grid suspension systems or other items manufactured in accordance with this specification.
3.2.2 nonstructural wall stud, n—a member in a steel framed wall system which is limited to a lateral (transverse) load of not
more than 10 lb/ft (480 Pa), a superimposed vertical load, exclusive of sheathing materials, of not more than 100 lbf/ft (1460
N/m), or a superimposed vertical load of not more than 200 lbs (890 N).
4. Materials and Manufacture
4.1 Members shall be manufactured from steel meeting the requirements of Specification A1003/A1003M.
4.2 Members shall have a protective coating conforming to Specification in accordance A653/A653M G40 minimum or shall
have a protective coating with an equivalent corrosion resistance.with AISI S220, Section A5.
4.3 Members shall be manufactured from steel having a minimum thickness, individual measurement of 0.0179 in. (0.455 mm),
before application of protective coating.
5. Dimensions and Permissible Variations
5.1 Studs and rigid furring channels shall have a configuration and steel thickness such that the system in which they are used
will carry the design transverse loads without exceeding either the allowable stress of the steel or the allowable design deflection.
Main beams and cross furring of grid suspension systems shall be limited to a deflection of L/240. The manufacturer shall supply
sufficient data for calculating design performance.
NOTE 1—Allowable deflection varies depending on the cladding used and architectural requirements. Detailed requirements shall be specified in
application specifications.
5.1.1 Members, except main beams of grid suspension systems, shall be sufficiently rigid to permit penetration of the screw.
5.1.2 Minimum width of face to which gypsum board is screw-attached shall be not less than 1 ⁄4 in. (32 mm).
5.1.3 Minimum lip dimension shall be ⁄16 in. (5 mm). (See Fig. 1.)
FIG. 1 Minimum Drywall Stud Cross Section
C645 − 18
5.2 Members shall be manufactured within the limits as showncomply with the manufacturing tolerances as listed in Table 1
andAISI S220, Fig. 2.Section A6.4.
5.3 Rigid Furring Channels—Minimum depth shall be ⁄8 in. (22 mm). Minimum width of furring attachment flanges (see Fig.
32) shall be ⁄2 in. (12.7 mm).
5.4 Grid suspension systems include main beams and cross furring members which mechanically interlock to form a modular
supporting network. Length tolerance for grid suspension members shall be 6 ⁄16 in. (1.59 mm).
5.5 Runners (track) shall be formed in a U-shaped configuration, having web depth compatible with those of the studs of the
same nominal size. The runners (track) shall be designed such that when the studs are placed in both the top and bottom runners
(track), they are held by friction. Minimum height of flanges shall be 1 in. (25 mm).
6. Edges
6.1 Members shall be manufactured in such a fashion as to minimize burrs and sharp edges.
7. Cutouts
7.1 Cutouts shall not reduce the performance of the members in the gypsum board construction assembly below the specified
performance requirements.
8. Sectional Properties
8.1 The sectional properties of members shall be computed in accordance with AISI S100 (see Tables 21 and 32 and Figs. 1
and 32).
9. Performance Requirements
9.1 Penetration—When tested in accordance with Section 10, members shall be capable of pulling the head of the screw below
the surface of the gypsum board in less than 2 s without spin out.
9.2 Members that can show certified third party testing in accordance with ICC-ES-AC86 (Approved May 2012), and conform
to the limiting height tables in Specification C754, need not meet the minimum thickness limitation set forth in subsection 4.3 or
the minimum section properties set forth in subsection 8.1.
10. Penetration Test
10.1 Significance and Use—This test method provides a procedure for evaluating the member’s ability to pull the head of a
screw below the surface of gypsum wallboard. It shall be used to determine compliance with this specification. The degree of
performance of this test method with service performance has not been determined.
10.2 Apparatus Shall Satisfy the Following:
10.2.1 Power-Driven Drill Screw Gun, capable of 4000 rpm (free spindle speed) with a depth-sensitive nose piece, supplied
with a screw driving bit to fit the screw used in the test.
10.2.2 Stop Watch, capable of being read to the nearest 0.1 s.
10.3 Materials Shall Satisfy the Following:
10.3.1 Gypsum Wallboard—Specification C1396/C1396M, Type X, ⁄8 in. (16 mm) thick.
10.3.2 Screws—Specification C1002, Type S, minimum 1 in. (25.4 mm) long.
10.3.3 Paper Joint Tape—Specification C475/C475M.
10.4 Sampling—One member shall be selected from each bundle or package, but not more than ten from any one shipment for
testing.
10.5 Specimen Preparation:
10.5.1 Each member to be tested shall be cut into test specimens not less than 18 in. (460 mm) long.
10.5.2 For each test, one piece of gypsum wallboard, 6 in. (150 mm) square, shall be cut from not less than 12 in. (300 mm)
from the edge or end of the gypsum wallboard.
10.5.3 For each test, four pieces of paper joint tape, 2 in. (50 mm) square shall be cut.
FIG. 32 Hat Furring Channel Cross Section
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