ASTM C920-18

Standard Specification for Elastomeric Joint Sealants

ABSTRACT
This specification covers the properties of a cured single- or multicomponent cold-applied elastomeric joint sealant for sealing, caulking, or glazing operations on buildings, plazas, and decks for vehicular or pedestrian use, and types of construction other than highway and airfield pavements and bridges. A sealant qualifying under this specification shall be classified as to type, grade, class and use as follows: type S - a single-component sealant, type M - a multicomponent sealant, grade P - a pourable or selfleveling sealant, grade NS - a nonsag or gunnable sealant, class 100/50, class 50, class 35, class 25, class 12.5, use T, use NT, use I, use M, use G, use A, and use O. A single-component sealant shall be a uniform mixture of a consistency suitable for immediate application by hand or pressure caulking gun or by hand tool. A multicomponent chemically curing sealant shall be furnished in two or more components. A single-component and multicomponent sealant, when stored in the original unopened container at temperatures of not more than 27°C (80°F) shall be capable of meeting the requirements for at least 6 months after date of delivery. Grade P (pourable or selfleveling) sealant shall have the required flow characteristics, it shall exhibit a smooth, level surface. Grade NS or gunnable sealant shall have the required flow characteristics such that when tested in vertical displacement. Type S, grade P, and grade NS sealant shall not be less than the given extrusion rate when tested. Type M and grade P sealant, when tested shall be not less than the given extrudable rate 3 h after mixing. Use T (traffic) sealant shall have a hardness reading, after being properly cured, of not less than 25 or more than 50 when tested. Use NT (nontraffic) sealant shall have a hardness reading, after being properly cured, of not less than 15 or more than 50 when tested. The sealant shall not lose more than 7 % of its original weight or show any cracking or chalking when tested. There shall be no transfer of the sealant to the polyethylene film when tested at 72 h. The sealant shall not cause any visible stain on the top surface of a white cement mortar base when tested. The adhesion and cohesion after cyclic movement shall be tested to meet the requirements prescribed. The adhesion-in-peel test shall be performed to meet the requirements precribed. The adhesion-in-peel after ultraviolet exposure through glass shall be determined to meet the requirements prescribed. The accelerated weathering effects, and sealants exposed to continuous immersion shall be determined to meet the requirements prescribed.
SIGNIFICANCE AND USE
7.1 This specification covers several classifications of sealants as described in Section 4 for various applications. It should be recognized by the purchaser or design professional that not all sealants meeting this specification are suitable for all applications and all substrates. It is essential, therefore, that the applicable type, grade, class, and use be specified so that the proper classification of sealant is provided for the intended use. Test methods relate to special standard specimen substrates of mortar, glass, and aluminum. If tests are required using substrates in addition to or other than the standard, they should be so specified for testing.
SCOPE
1.1 This ASTM specification covers the properties of a cured single- or multicomponent cold-applied elastomeric joint sealant for sealing, caulking, or glazing operations on buildings, plazas, and decks for vehicular or pedestrian use, and types of construction other than highway and airfield pavements and bridges.  
1.2 A sealant meeting the requirements of this specification shall be designated by the manufacturer to be one or more of the types, classes, grades, and uses defined in Section 7.  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.  
1.4 Thi...

General Information

• Status: Published
• Publication Date: 31-Dec-2017
• ICS: 91.100.50 - Binders. Sealing materials
• Technical Committee: C24 - Building Seals and Sealants
• Drafting Committee: C24.10 - Specifications, Guides and Practices

Relations

• Refers: ASTM C794-15 - Standard Test Method for Adhesion-in-Peel of Elastomeric Joint Sealants
• Effective Date: 01-Mar-2015
• Refers: ASTM C794-15a - Standard Test Method for Adhesion-in-Peel of Elastomeric Joint Sealants
• Effective Date: 01-Jul-2015
• Refers: ASTM C717-16 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Sep-2016
• Refers: ASTM C717-16a - Standard Terminology of Building Seals and Sealants
• Effective Date: 15-Nov-2016
• Refers: ASTM C717-17 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Jan-2017
• Refers: ASTM C717-17a - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Nov-2017
• Refers: ASTM C717-18 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Mar-2018
• Refers: ASTM C717-19 - Standard Terminology of Building Seals and Sealants
• Effective Date: 01-Mar-2019
• Refers: ASTM C1247-20 - Standard Test Method for Durability of Sealants Exposed to Continuous Immersion in Liquids
• Effective Date: 01-Jan-2020
• Refers: ASTM C639-15(2020) - Standard Test Method for Rheological (Flow) Properties of Elastomeric Sealants
• Effective Date: 01-May-2020
• Refers: ASTM C639-15 - Standard Test Method for Rheological (Flow) Properties of Elastomeric Sealants
• Effective Date: 01-Jun-2015
• Refers: ASTM C719-14 - Standard Test Method for Adhesion and Cohesion of Elastomeric Joint Sealants Under Cyclic Movement (Hockman Cycle)
• Effective Date: 15-Jul-2014
• Referred By: ASTM C1127/C1127M-15(2023) - Standard Guide for Use of High Solids Content, Cold Liquid-Applied Elastomeric Waterproofing Membrane with an Integral Wearing Surface
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1472-16(2022) - Standard Guide for Calculating Movement and Other Effects When Establishing Sealant Joint Width
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1401-23 - Standard Guide for Structural Sealant Glazing
• Effective Date: 01-Jan-2018
• Referred By: ASTM C840-20 - Standard Specification for Application and Finishing of Gypsum Board
• Effective Date: 01-Jan-2018
• Referred By: ASTM E2398/E2398M-19 - Standard Test Method for Water Capture and Media Retention of Geocomposite Drain Layers for Vegetative (Green) Roof Systems
• Effective Date: 01-Jan-2018
• Referred By: ASTM E2112-23 - Standard Practice for Installation of Exterior Windows, Doors and Skylights
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1781/C1781M-21 - Standard Test Method for Surface Infiltration Rate of Permeable Unit Pavement Systems
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1564-20 - Standard Guide for Use of Silicone Sealants for Protective Glazing Systems
• Effective Date: 01-Jan-2018
• Referred By: ASTM E2266-22 - Standard Guide for Design and Construction of Low-Rise Frame Building Wall Systems to Resist Water Intrusion
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1193-16(2023) - Standard Guide for Use of Joint Sealants
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1732-19 - Standard Practice for Installation of Concrete Floor Tiles
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1248-22 - Standard Test Method for Staining of Porous Substrate by Joint Sealants
• Effective Date: 01-Jan-2018
• Referred By: ASTM C898/C898M-09(2017) - Standard Guide for Use of High Solids Content, Cold Liquid-Applied Elastomeric Waterproofing Membrane with Separate Wearing Course
• Effective Date: 01-Jan-2018
• Referred By: ASTM C981-20 - Standard Guide for Design of Built-Up Bituminous Membrane Waterproofing Systems for Building Decks
• Effective Date: 01-Jan-2018
• Referred By: ASTM F3097-22 - Standard Practice for Installation of an Outside Sewer Service Cleanout through a Minimally Invasive Small Bore Vacuum Excavation and Same Day Restoration
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1481-12(2017) - Standard Guide for Use of Joint Sealants with Exterior Insulation and Finish Systems (EIFS)
• Effective Date: 01-Jan-2018
• Referred By: ASTM C919-22 - Standard Practice for Use of Sealants in Acoustical Applications
• Effective Date: 01-Jan-2018
• Referred By: ASTM C679-15(2022) - Standard Test Method for Tack-Free Time of Elastomeric Sealants
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1635-22 - Standard Test Method to Evaluate Adhesion/Cohesion Properties of a Sealant at Fixed Extension
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1021-08(2023) - Standard Practice for Laboratories Engaged in Testing of Building Sealants
• Effective Date: 01-Jan-2018
• Referred By: ASTM C1701/C1701M-17a - Standard Test Method for Infiltration Rate of In Place Pervious Concrete
• Effective Date: 01-Jan-2018

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: C920 −18
Standard Specification for
1
Elastomeric Joint Sealants
This standard is issued under the fixed designation C920; 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.
1. Scope C717 Terminology of Building Seals and Sealants
C719 Test Method for Adhesion and Cohesion of Elasto-
1.1 This ASTM specification covers the properties of a
meric Joint Sealants Under Cyclic Movement (Hockman
cured single- or multicomponent cold-applied elastomeric joint
Cycle)
sealant for sealing, caulking, or glazing operations on
C793 Test Method for Effects of Laboratory Accelerated
buildings, plazas, and decks for vehicular or pedestrian use,
Weathering on Elastomeric Joint Sealants
and types of construction other than highway and airfield
C794 Test Method forAdhesion-in-Peel of Elastomeric Joint
pavements and bridges.
Sealants
1.2 A sealant meeting the requirements of this specification
C1183 Test Method for Extrusion Rate of Elastomeric Seal-
shall be designated by the manufacturer to be one or more of
ants
the types, classes, grades, and uses defined in Section 7.
C1193 Guide for Use of Joint Sealants
C1246 Test Method for Effects of Heat Aging on Weight
1.3 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information Loss, Cracking, and Chalking of Elastomeric Sealants
After Cure
only.
C1247 Test Method for Durability of Sealants Exposed to
1.4 This standard is similar, but not identical, to ISO 11600
Continuous Immersion in Liquids
and ISO 11618.
C1442 Practice for Conducting Tests on Sealants Using
1.5 This international standard was developed in accor-
Artificial Weathering Apparatus
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the 3. Terminology
Development of International Standards, Guides and Recom-
3.1 Definitions—Refer to Terminology C717 for definitions
mendations issued by the World Trade Organization Technical
of the following terms used in this specification: adhesive
Barriers to Trade (TBT) Committee.
failure, caulking, chemically curing sealant, cohesive failure,
cure, cured, elastomeric, glazing, joint, primer, seal, sealant,
2. Referenced Documents
and standard conditions.
2
2.1 ASTM Standards:
C510 Test Method for Staining and Color Change of Single- 4. Classification of Sealants
or Multicomponent Joint Sealants
4.1 A sealant qualifying under this specification shall be
C639 Test Method for Rheological (Flow) Properties of
classified as to type, grade, class, and use as follows:
Elastomeric Sealants
4.1.1 Type S—A single-component sealant.
C661 Test Method for Indentation Hardness of Elastomeric-
4.1.2 Type M—A multicomponent sealant.
Type Sealants by Means of a Durometer
4.1.3 Grade P—A pourable or selfleveling sealant that has
C679 Test Method for Tack-Free Time of Elastomeric Seal-
sufficient flow to form a smooth, level surface when applied in
ants
a horizontal joint at 4.4°C (40°F).
4.1.4 Grade NS—Anonsag or gunnable sealant that permits
1
This specification is under the jurisdiction of ASTM Committee C24 on
application in joints on vertical surfaces without sagging or
Building Seals and Sealants and is the direct responsibility of Subcommittee C24.10
slumping when applied at temperatures between 4.4 and 50°C
on Specifications, Guides and Practices.
(40 and 122°F).
Current edition approved Jan. 1, 2018. Published January 2018. Originally
4.1.5 Class 100/50—Asealant that when tested for adhesion
approved in 1979. Last previous edition approved in 2014 as C920 – 14a. DOI:
10.1520/C0920-18.
and cohesion under cyclic movement (8.8) shall withstand an
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
increase of at least 100 % and a decrease of at least 50 % of the
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
joint width as measured at the time of application, and, in
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. addition, meet all the requirements of this specification.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
C920 − 18
4.1.6 Class 50—Asealant that when tested for adhesion and shall be uniform and
...

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: C920 − 14a C920 − 18
Standard Specification for
1
Elastomeric Joint Sealants
This standard is issued under the fixed designation C920; 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.
1. Scope
1.1 This ASTM specification covers the properties of a cured single- or multicomponent cold-applied elastomeric joint sealant
for sealing, caulking, or glazing operations on buildings, plazas, and decks for vehicular or pedestrian use, and types of
construction other than highway and airfield pavements and bridges.
1.2 A sealant meeting the requirements of this specification shall be designated by the manufacturer to be one or more of the
types, classes, grades, and uses defined in Section 7.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard is similar, but not identical, to ISO 11600.11600 and ISO 11618.
1.5 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
2.1 ASTM Standards:
C510 Test Method for Staining and Color Change of Single- or Multicomponent Joint Sealants
C639 Test Method for Rheological (Flow) Properties of Elastomeric Sealants
C661 Test Method for Indentation Hardness of Elastomeric-Type Sealants by Means of a Durometer
C679 Test Method for Tack-Free Time of Elastomeric Sealants
C717 Terminology of Building Seals and Sealants
C719 Test Method for Adhesion and Cohesion of Elastomeric Joint Sealants Under Cyclic Movement (Hockman Cycle)
C793 Test Method for Effects of Laboratory Accelerated Weathering on Elastomeric Joint Sealants
C794 Test Method for Adhesion-in-Peel of Elastomeric Joint Sealants
C1183 Test Method for Extrusion Rate of Elastomeric Sealants
C1193 Guide for Use of Joint Sealants
C1246 Test Method for Effects of Heat Aging on Weight Loss, Cracking, and Chalking of Elastomeric Sealants After Cure
C1247 Test Method for Durability of Sealants Exposed to Continuous Immersion in Liquids
C1442 Practice for Conducting Tests on Sealants Using Artificial Weathering Apparatus
3. Terminology
3.1 Definitions—Refer to Terminology C717 for definitions of the following terms used in this specification: adhesive failure,
caulking, chemically curing sealant, cohesive failure, cure, cured, elastomeric, glazing, joint, primer, seal, sealant, and standard
conditions.
4. Classification of Sealants
4.1 A sealant qualifying under this specification shall be classified as to type, grade, class, and use as follows:
4.1.1 Type S—A single-component sealant.
1
This specification is under the jurisdiction of ASTM Committee C24 on Building Seals and Sealants and is the direct responsibility of Subcommittee C24.10 on
Specifications, Guides and Practices.
Current edition approved June 1, 2014Jan. 1, 2018. Published July 2014January 2018. Originally approved in 1979. Last previous edition approved in 2014 as
C920 – 14.C920 – 14a. DOI: 10.1520/C0920-14A.10.1520/C0920-18.
2
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
1

---------------------- Page: 1 ----------------------
C920 − 18
4.1.2 Type M—A multicomponent sealant.
4.1.3 Grade P—A pourable or selfleveling sealant that has sufficient flow to form a smooth, level surface when applied in a
horizontal joint at 4.4°C (40°F).
4.1.4 Grade NS—A nonsag or gunnable sealant that permits application in joints on vertical surfaces without sagging or
slumping when applied at temperatures between 4.4 and 50°C (40 and 122°F).
4.1.5 Class 100/50—A sealant that when tested for adhesion and cohesion under cyclic movement (8.8) shall withstand an
increase of at least 100 % and a decrease of at least 50 % of the joint width as mea
...