ASTM C1178/C1178M-24

Standard Specification for Coated Glass Mat Water-Resistant Gypsum Backing Panel

ABSTRACT
This specification covers coated glass mat water-resistant gypsum backing panel designed for use on ceilings and walls in bath and shower areas as a base for the application of ceramic or plastic tile. Coated glass mat water-resistant gypsum backing panel shall consist of a noncombustible water-resistant gypsum core, surfaced with glass mat, partially or completely embedded in the core, and with a water-resistant coating on one surface. The specimens shall be tested for flexural strength, humidified deflection, core hardness, end hardness, edge hardness, nail pull resistance, water resistance, and surface water absorption. Coated glass mat water-resistant gypsum backing panel shall have surfaces true and free of imperfections that render the panel unfit for its designed use.
SCOPE
1.1 This specification covers coated glass mat water-resistant gypsum backing panel designed for use on ceilings and walls in bath and shower areas as a base for the application of ceramic or plastic tile.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. Within the text, the SI units are shown in brackets.  
1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.  
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.

General Information

• Status: Published
• Publication Date: 30-Apr-2024
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: C11 - Gypsum and Related Building Materials and Systems
• Drafting Committee: C11.01 - Specifications and Test Methods for Gypsum Products

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: C1178/C1178M − 24
Standard Specification for
Coated Glass Mat Water-Resistant Gypsum Backing Panel
This standard is issued under the fixed designation C1178/C1178M; 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* Certification, Packaging, Marking, Shipping, Handling,
and Storage of Gypsum Panel Products
1.1 This specification covers coated glass mat water-
D3273 Test Method for Resistance to Growth of Mold on the
resistant gypsum backing panel designed for use on ceilings
Surface of Interior Coatings in an Environmental Cham-
and walls in bath and shower areas as a base for the application
ber
of ceramic or plastic tile.
E119 Test Methods for Fire Tests of Building Construction
1.2 The values stated in either SI units or inch-pound units
and Materials
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents; therefore, each
3. Terminology
system shall be used independently of the other. Combining
3.1 Definitions used in this specification shall be in accor-
values from the two systems may result in non-conformance
dance with Terminology C11.
with the standard. Within the text, the SI units are shown in
brackets.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 nominal thickness, n—the manufacturer stated frac-
1.3 The text of this standard references notes and footnotes
tional value of thickness of gypsum panel products.
that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered
as requirements of the standard. 4. Materials and Manufacture
1.4 This international standard was developed in accor-
4.1 Coated glass mat water-resistant gypsum backing panel
dance with internationally recognized principles on standard-
shall consist of glass mat facers and a noncombustible,
ization established in the Decision on Principles for the
water-resistant core, composed of essentially gypsum comply-
Development of International Standards, Guides and Recom-
ing with Specification C22. The glass mat facers shall be
mendations issued by the World Trade Organization Technical
partially or completely embedded in the core, with a water-
Barriers to Trade (TBT) Committee.
resistant coating on one surface.
4.2 Coated glass mat water-resistant gypsum panels, type X
2. Referenced Documents
(special fire-resistant) designates glass mat gypsum panels
2.1 ASTM Standards:
complying with this specification that provide not less than 1-h
C11 Terminology Relating to Gypsum and Related Building
5 3
fire resistance rating for boards ⁄8 in. [15.9 mm] thick or ⁄4-h
Materials and Systems
fire resistance rating for panels ⁄2 in. [12.7 mm] thick, applied
C22 Specification for Gypsum
parallel with and on each side of load bearing 2 by 4 wood
C473 Test Methods for Physical Testing of Gypsum Panel
studs spaced 16 in. [406 mm] on center with 6d coated nails,
Products
1 ⁄8 in. [48-mm] long, 0.0915 in. [2.3 mm] diameter
C645 Specification for Nonstructural Steel Framing Mem-
shank, ⁄4 in. [6.4 mm] diameter heads, spaced 7 in. [178 mm]
bers
on center with glass mat gypsum panel joints staggered 16 in.
C1264 Specification for Sampling, Inspection, Rejection,
[406 mm] on each side of the partition and tested in accordance
with Test Methods E119.
This specification is under the jurisdiction of ASTM Committee C11 on
NOTE 1—Consult manufacturers for independent test data on assembly
Gypsum and Related Building Materials and Systems and is the direct responsibility
details and fire resistance ratings for other types of construction. See fire
of Subcommittee C11.01 on Specifications and Test Methods for Gypsum Products.
test reports or listings from recognized fire testing laboratories for
Current edition approved May 1, 2024. Published May 2024. Originally
assembly particulars, materials, and ratings.
approved in 1991. Last previous edition approved in 2018 as C1178/C1178M – 18.
DOI: 10.1520/C1178_C1178M-24.
4.3 Coated glass mat water-resistant gypsum backing
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
panels, mold resistant, designates gypsum panels having not
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
more than 20 % mold growth, based on surface area coverage,
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. when tested in accordance with Test Method D3273.
*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
C1178/C1178M − 24
5. Physical Properties 5.2.6 Surface Water Absorption—Specimens shall have an
average surface water absorption of the face side of the panel
5.1 Specimens shall be taken from the samples obtained in
not more than 0.5 g after 2 h of elapsed time.
accordance with Specification C1264.
5.2 Specimens shall be tested in accordance with Test 6. Dimensions and Tolerances
Methods C473.
6.1 Specimens shall be taken from the samples obtained in
5.2.1 Flexural Strength—The specimens shall be tested face
accordance with Specification C1264.
up and face down. The average breaking load shall not be less
6.2 Thickness, width, and length shall be determined in
than the following:
accordance with Test Methods C473.
Method B
6.2.1 Thickness—The nominal thickness shall be ⁄4 in.,
Load, lbf [N]
5 1 5
⁄16 in., ⁄2 in., or ⁄8 in. [6.4 mm, 7.9 mm, 12.7 mm, or
Nominal Thickness, Bearing edges perpendicular Bearing edges parallel
15.9 mm], with thickness tolerances of 6 0.015 in.
in. [mm] to the board edge to the board edge
[6 0.40 mm] and local variations of 6 0.030 in. [6 0.80 mm].
⁄4 [6.4] 50 [222] 40 [178] 6.2.2 Width—The nominal width shall be up to 48 in.
⁄16 [7.9] 65 [289] 50 [222]
[1220 mm], with a tolerance of ⁄32 in. [3 mm] under the
⁄2 [12.7] 100 [445] 8
...

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: C1178/C1178M − 18 C1178/C1178M − 24
Standard Specification for
Coated Glass Mat Water-Resistant Gypsum Backing Panel
This standard is issued under the fixed designation C1178/C1178M; 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 coated glass mat water-resistant gypsum backing panel designed for use on ceilings and walls in bath
and shower areas as a base for the application of ceramic or plastic tile.
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard. Within the text, the SI units are shown in brackets.
1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes
(excluding those in tables and figures) shall not be considered as requirements of the standard.
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:
C11 Terminology Relating to Gypsum and Related Building Materials and Systems
C22 Specification for Gypsum
C473 Test Methods for Physical Testing of Gypsum Panel Products
C645 Specification for Nonstructural Steel Framing Members
C1264 Specification for Sampling, Inspection, Rejection, Certification, Packaging, Marking, Shipping, Handling, and Storage of
Gypsum Panel Products
D3273 Test Method for Resistance to Growth of Mold on the Surface of Interior Coatings in an Environmental Chamber
E119 Test Methods for Fire Tests of Building Construction and Materials
3. Terminology
3.1 Definitions used in this specification 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 C11.01 on Specifications and Test Methods for Gypsum Products.
Current edition approved June 1, 2018May 1, 2024. Published June 2018May 2024. Originally approved in 1991. Last previous edition approved in 20132018 as
C1178/C1178M – 13. DOI: 10.1520/C1178_C1178M-18.18. DOI: 10.1520/C1178_C1178M-24.
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.
*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
C1178/C1178M − 24
3.2.1 glass mat, n—a mat of glass fibers with or without a binder.
3.2.2 edge, n—the bound edge as manufactured.
3.2.3 face, n—the coated surface.
3.2.1 nominal thickness, n—the manufacturer-stated manufacturer stated fractional value of thickness of the gypsum panel product
expressed in decimal value to the nearest one-thousandth (0.001) of an inch.gypsum panel products.
4. Materials and Manufacture
4.1 Coated glass mat water-resistant gypsum backing panel Coated glass mat water-resistant gypsum backing panel shall consist
of a noncombustible water-resistant core, glass mat facers and a noncombustible, water-resistant core, composed of essentially
gypsum complying with Specification C22, surfaced with glass mat, . The glass mat facers shall be partially or completely
embedded in the core, and with a water-resistant coating on one surface.
4.2 Coated glass mat water-resistant gypsum panels, type X (special fire-resistant) designates glass mat gypsum panels complying
5 3
with this specification that provide not less than 1-h fire resistance rating for boards ⁄8 in. [15.9 mm] thick or ⁄4-h fire resistance
rating for panels ⁄2 in. [12.7 mm] thick, applied parallel with and on each side of load bearing 2 by 4 wood studs spaced 16 in.
7 1
[406 mm] on center with 6d coated nails, 1 ⁄8 in. [48-mm] long, 0.0915 in. [2.3 mm] diameter shank, ⁄4 in. [6.4 mm] diameter
heads, spaced 7 in. [178 mm] on center with glass mat gypsum panel joints staggered 16 in. [406 mm] on each side of the partition
and tested in accordance with Test Methods E119.
NOTE 1—Consult manufacturers for independent test data on assembly details and fire resistance ratings for other types of construction. See fire test reports
or listings from recognized fire testing laboratories for assembly particulars, materials, and ratings.
4.3 Coated glass mat water-resistant gypsum backing panels, mold resistant, designates gypsum panels having not more than 20 %
mold growth, based on surface area coverage, when tested in accordance with Test Method D3273.
5. Physical Properties
5.1 Specimens shall be taken from the samples obtained in accordance with Specification C1264.
5.2 Specimens shall be tested in accordance with Test Methods C473.
5.2.1 Flexural Strength—The specimens shall be tested face up and face down. The average breaking load shall not be less than
the following:
Method B
Load, lbf [N]
Nominal Thickness, Bearing edges perpendicular Bearing edges parallel
in. [mm] to the board edge to the board edge
⁄4 [6.4] 50 [222] 40 [178]
⁄16 [7.9] 65 [289] 50 [222]
⁄2 [12.7] 100 [445] 80 [356]
⁄8 [15.9] 140 [623] 100 [445]
5.2.2 Humidified Deflection—Specimens shall have an average deflection of not more than the following:
Nominal Thickness, Humidified deflection,
in. [mm] eighths of an in. [mm]
⁄4 [6.4] not required
⁄16 [7.9] not required
⁄2 [12.7] 2 [6]
⁄8 [15.9] 1 [3]
C1178/C1178M − 24
5.2.3 Core, End and Edge Hardness—Specimens shall have an average hardness of not less than 15 lbf [67 N] when tested in
accordance with Method B.
5.2.4 Nail Pull Resistance—Specimens shall have an average nail pull resistance of not less than the following when tested in
accordance with Method B:
Nominal Thickness, in. [mm] Nail pull resis
...