ASTM C1858-17a(2021)

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: C1858 − 17a (Reapproved 2021)
Standard Practice for
Design, Construction, and Material Requirements for Direct
Hung Suspended T-bar Type Ceiling Systems Intended to
Receive Gypsum Panel Products in Areas Subject to
Earthquake Ground Motions
This standard is issued under the fixed designation C1858; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This practice covers the installation requirements of
direct hung suspended t-bar type ceiling systems intended to
2. Referenced Documents
receive gypsum panel products constructed as flat, single level,
2.1 ASTM Standards:
surrounded on all sides by a wall, bulk head, or soffit braced to
A641/A641M Specification for Zinc–Coated (Galvanized)
the building structure to resist the effects of earthquake ground
Carbon Steel Wire
motions.
C11 Terminology Relating to Gypsum and Related Building
1.2 Ceiling assembly shall not be intended to support live 4
Materials and Systems
loads.
C645 Specification for Nonstructural Steel Framing Mem-
1.3 This standard addresses ceiling systems with dead loads bers
2 2
up to 10 lbs/ft (48.8 kg/m ). C754 Specification for Installation of Steel Framing Mem-
bers to Receive Screw-Attached Gypsum Panel Products
1.4 The values stated in either SI units or inch-pound units
C1177/C1177M Specification for Glass Mat Gypsum Sub-
are to be regarded separately as standard. The values stated in
strate for Use as Sheathing
each system may not be exact equivalents; therefore, each
C1396 Specification for Gypsum Board
system shall be used independently of the other. Combining
C1658/C1658M Specification for Glass Mat Gypsum Pan-
values from the two systems may result in non-conformance
els
with the standard.
E3090/E3090M Test Methods for Strength Properties of
1.5 The text of this standard references notes and footnotes
Metal Ceiling Suspension Systems
which provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered 3. Terminology
as requirements of the standard
3.1 Definitions—Terms shall be as defined in Terminology
1.6 This standard does not purport to address all of the
C11.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 counter sloping wire, n—opposing suspension wire
priate safety, health, and environmental practices and deter-
intended to counteract the force of an out of plumb suspension
mine the applicability of regulatory limitations prior to use.
wire and maintain alignment of the system.
1.7 This international standard was developed in accor-
3.2.2 cross runner, n—the secondary support members or
dance with internationally recognized principles on standard-
cross beams of a mechanical ceiling suspension system trans-
ization established in the Decision on Principles for the
ferring ceiling load to the main runner.
Development of International Standards, Guides and Recom-
3.2.3 diaphragm, n—horizontal system acting to transmit
lateral forces to the vertical resisting elements.
1 3.2.4 direct hung ceiling, n—load carrying ceiling compo-
This practice is under the jurisdiction of ASTM Committee C11 on Gypsum
and Related Building Materials and Systems and is the direct responsibility of nents that are fastened directly to structure.
Subcommittee C11.03 on Specifications for the Application of Gypsum and Other
Products in Assemblies.
Current edition approved Dec. 1, 2021. Published December 2021. Originally Annual ASTM Book of Standards, Vol.01.06.
approved in 1991. Last previous edition approved in 2017 as C1858 – 17a. DOI: Annual ASTM Book of Standards, Vol.04.01.
10.1520/C1858-17AR21. Annual ASTM Book of Standards, Vol.04.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1858 − 17a (2021)
3.2.5 main runner, n—the primary or main beams (supports) and sharply bent to prevent any vertical movement or rotation
of the ceiling suspension system. of the member within the loops. The wire shall be wrapped
around itself a minimum of three full turns (360° each) within
3.2.6 t-bar ceiling, n—modular interlocking suspended ceil-
a 3-in [75 mm] length. For safety purposes, the bottom of the
ing system containing framing members with inverted
hanger wires shall either be cut close to the vertical portion of
T-shaped profiles.
the wire or shall be bent upward parallel to the vertical portion
4. Summary of Practice
of the hanger wire.
7.2.6 Hangers formed from galvanized sheet metal stock
4.1 This practice outlines the design and installation re-
shall be suitable for suspending main runners from an existing
quirements of direct hung gypsum t-bar ceilings exempt from
structure provided
...