ASTM C1381/C1381M-23

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: C1381/C1381M − 23
Standard Specification for
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Molded Glass Fiber Reinforced Gypsum Parts
This standard is issued under the fixed designation C1381/C1381M; 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* 3.2 Definitions of Terms Specific to This Standard:
3.2.1 control thickness, n—the thickness of the GRG part
1.1 This specification covers molded glass fiber reinforced
where abutting other GRG parts, other products or at fastening
gypsum (GRG) parts, which are nonload-bearing, thin-shell,
points.
ornamental shapes for architectural embellishment of interior
building construction. 3.2.2 embedments, n—materials encapsulated into the part
for the purpose of suspension, attachment, and stiffening.
1.2 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. Within the text, the 3.2.3 finish surface, n—a surface against a mold.
SI units are shown in brackets. The values stated in each
3.2.4 GRG part, n—an individual molded component used
system may not be exact equivalents; therefore, each system
as architectural embellishment.
shall be used independently of the other. Combining values
3.2.5 GRG product, n—combination of GRG parts used as
from the two systems may result in non-conformance with the
architectural embellishment.
standard.
3.2.6 mock-up, n—a presentation assembly of GRG parts
1.3 The information presented refers to the molded surface
defined by the purchase agreement.
of the part.
3.2.7 part thickness, n—thickness of a part at any measure-
1.4 The text of this standard references footnotes, which
ment point.
provide explanatory material. These footnotes shall not be
considered as requirements of the standard.
4. Materials and Manufacture
1.5 This international standard was developed in accor-
4.1 Materials—GRG parts shall be produced using the same
dance with internationally recognized principles on standard-
materials used to make the composites in conformance with
ization established in the Decision on Principles for the
Specification C1355/C1355M.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.2 Manufacture:
Barriers to Trade (TBT) Committee.
4.2.1 GRG parts shall be manufactured from the mixed
slurry of gypsum cement, potable water and additives, when
2. Referenced Documents
used, and not less than 5 % by weight glass fiber reinforcement
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2.1 ASTM Standards:
using either the hand lay-up or the spray-up process in a mold.
C11 Terminology Relating to Gypsum and Related Building
4.2.2 GRG parts shall be produced according to approved
Materials and Systems
shop drawings.
C1355/C1355M Specification for Glass Fiber Reinforced
4.2.3 Shop drawings shall specify part dimensions,
Gypsum Composites
quantities, recommended attachment points and methods,
3. Terminology reinforcements, embedments, and tolerance.
3.1 Definitions—Definitions of terms shall be in accordance
5. Mechanical Properties
with Terminology C11.
5.1 GRG parts shall be made from materials to make
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This specification is under the jurisdiction of ASTM Committee C11 on
composites having properties in accordance with Specification
Gypsum and Related Building Materials and Systems and is the direct responsibility
C1355/C1355M.
of Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products.
Current edition approved March 1, 2023. Published March 2023. Originally
approved in 1998. Last previous edition approved in 2018 as C1381/
6. Dimensions and Tolerances of GRG Parts
C1381M – 97 (2018). DOI: 10.1520/C1381_C1381M-23.
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6.1 Part Thickness—The thickness of the GRG part shall be
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
not less than ⁄16 in. [5 mm].
Standards volume information, refer to the standard’s Document Summary page on
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the ASTM website. 6.2 Control Thickness, shall be not less than ⁄16 in. [8 mm].
*A Summary of Changes section appears at the end of this standard
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C1381/C1381M − 23
6.3 Straightness—At any point on a line generally along a 10. Rejection and Rehearing
plane, an edge, or a surface, the molded side of the part shall
10.1 Rejection of GRG parts th
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