ASTM C920-11 Standard Specification for Elastomeric Joint Sealants

The standard “ASTM C920-11 Standard Specification for Elastomeric Sealants” published by the American Society for Testing and Materials (ASTM) describes the properties of cured single or plural component cold-applied elastomeric sealants for sealing, caulking, or glazing operations on buildings, plazas, and decks intended for vehicular or pedestrian use, and on construction types other than highway and airport pavements and bridges.

A sealant meeting the requirements of this standard is determined by the manufacturer to be one or more of the types, classes, grades and uses defined in this standard.

For the purposes of this standard, the definitions of terms such as adhesive failure, caulking, chemically cured sealant, cohesive failure, cure, cured, elastomeric, glazing, joint, primer, sealant, and sealant are defined in ASTM C717-24 Standard Terminology for Building Sealants and Sealants.

A sealant conforming to this standard shall be classified as follows in terms of type, grade, class and use:

• Type S: A single component sealant.
• Type M: A multi-component sealant.
• Class P: A pourable or self-leveling sealant with sufficient flow to produce a smooth, flat surface when applied to a horizontal joint at 4,4 degrees Celsius.
• Class NS: A non-sag or gun-applied sealant that allows application to joints on vertical surfaces without sagging or sagging when applied at temperatures between 4,4 and 50 degrees.
• Class 100/50: A sealant that, when tested for adhesion and cohesion under cyclic action, will withstand at least 100 percent increase and at least 50 percent decrease of the joint width measured during application and will also meet all the requirements of this specification.
• Class 50: A sealant that, when tested for adhesion and cohesion under cyclic action, will withstand increases and decreases of at least 50 percent of the measured joint width during application and will also meet all the requirements of this specification.
• Class 35: A sealant that, when tested for adhesion and cohesion under cyclic action, will withstand increases and decreases of at least 35 percent of the measured joint width during application and will also meet all the requirements of this specification.
• Class 25: A sealant that will meet all the requirements of this specification when tested for adhesion and cohesion under cyclic action and will withstand increases and decreases of at least 25 percent of the joint width measured at the time of application.
• Class 12 1⁄2: A sealant that will meet all the requirements of this specification when tested for adhesion and cohesion under cyclic action and will withstand increases and decreases of at least 12 1⁄2 percent of the joint width measured at the time of application.
• Usage T1: A sealant designed for use in joints in pedestrian and vehicular traffic areas such as walkways, plazas, decks and parking garages where a higher modulus, more robust sealant is desired.
• Use T2: A sealant designed for use in joints in pedestrian and vehicular traffic areas (e.g., walkways, plazas, decks, and parking garages) where a lower modulus, softer sealant is desired. Hardness alone does not correlate to joint performance. Joints in pedestrian and vehicular traffic areas (e.g., walkways, plazas, decks, and parking garages) require appropriate design considerations such as material selection, overall joint design, manufacturer participation, and field testing.
• Usage NT: A sealant designed for use in joints in non-traffic areas.
• Use I: A sealant designed for use in joints permanently immersed in a liquid.
• Use M: A sealer that meets the requirements of this standard when tested on mortar samples in accordance with this standard.
• Use G: A sealant that meets the requirements of this specification when tested on glass samples in accordance with this standard.
• Usage A: A sealant that meets this specification when tested on aluminium specimens in accordance with this standard.
• Use O: A sealant that meets this specification when tested on substrates other than standard substrates in accordance with this standard.

A single component sealant should be a homogeneous mixture of consistency suitable for immediate application by hand or with a pressure caulking gun or hand tool. When fully cured, the sealant should form an elastomeric solid capable of maintaining a seal.

A multi-component chemically cured sealant shall be supplied in two or more components. The resulting mixture shall be homogeneous and of a consistency suitable for immediate application by hand or with a pressure caulking gun or hand tool. The sealant shall form an elastomeric solid when fully cured, capable of maintaining a seal.

Among the numerous testing, measurement, analysis and evaluation studies that our organization has carried out for businesses in various sectors, it also provides testing services defined in the "ASTM C920-11 Standard Specification for Elastomeric Joint Sealants" standard with its trained and expert staff and advanced technological equipment.