ASTM C661-15 (2022) PDF

Full title and description

ASTM C661-15(2022) — Standard Test Method for Indentation Hardness of Elastomeric-Type Sealants by Means of a Durometer. This test method describes a laboratory procedure for determining the indentation hardness of joint sealing compounds (single- and multicomponent) intended for use in building construction; results are expressed as durometer (indentation) hardness values and are intended for specification, quality control, and comparative evaluation of sealant materials.

Abstract

This standard specifies how to measure the indentation hardness of elastomeric-type sealants using a durometer. It defines specimen preparation and conditioning, the durometer measurement procedure, and reporting of results. The method yields an indentation value (not a direct measure of abrasion or wear resistance) useful for material comparison, specification compliance, and quality control.

General information

• Status: Active; reapproved (current edition) in 2022.
• Publication date: Originally approved 2015 (designation C661‑15); reapproval / current listing dated January 2022 (last updated Jan 17, 2022).
• Publisher: ASTM International.
• ICS / categories: 83.060; 91.100.50 (rubber; binders / sealing materials).
• Edition / version: C661‑15(2022) (also referenced as C0661‑15R22).
• Number of pages: 3.

Scope

This test method covers a laboratory procedure for determining indentation hardness of joint sealing compounds (single‑ and multicomponent) intended for use in building construction. The standard states the units of record, conditioning requirements, and the intended purpose: comparative hardness and specification checking rather than wear/abrasion performance prediction.

Key topics and requirements

• Purpose and significance: measures indentation hardness by durometer; results are used for specification and comparative testing but are not direct measures of abrasion or wear.
• Specimen preparation and conditioning: describes sample preparation, curing/conditioning periods and environmental conditions prior to measurement (to ensure repeatability).
• Instrumentation: use of a durometer (appropriate Shore scale for the material under test); typical practice in construction sealants is to report Shore A values (and Shore 00 for very soft materials where applicable).
• Measurement procedure and reporting: specified number of readings, averaging, and required reporting details so values are comparable between laboratories and suppliers.
• Application context: intended for joint sealing materials in building construction; supports specification compliance, material selection, and quality control.

Typical use and users

Used by materials laboratories, sealant manufacturers, quality/QA departments, specification writers, architects, and construction testing firms for verifying cured hardness of elastomeric joint sealants, comparing formulations, and ensuring products meet project or specification requirements.

Related standards

Commonly referenced with other sealant and test standards such as ASTM C920 (Specification for Elastomeric Joint Sealants) and other ASTM methods related to sealant properties and durability. Standards collections and distributors list C661 as referenced by several related ASTM documents in the C24 committee family.

Keywords

indentation hardness; durometer; elastomeric sealant; joint sealant; Shore A; Shore 00; building construction; quality control.

FAQ

Q: What is this standard?

A: ASTM C661‑15(2022) is a test method that specifies how to measure the indentation hardness of elastomeric‑type sealants using a durometer; it is intended for specification and comparative testing of joint sealing compounds.

Q: What does it cover?

A: It covers specimen preparation and conditioning, the durometer measurement procedure, reporting of results, and the intended interpretation (indentation hardness for comparison and QC rather than abrasion resistance).

Q: Who typically uses it?

A: Sealant manufacturers, independent testing labs, construction QA/QC teams, specifiers and architects, and anyone needing standardized hardness data for elastomeric joint sealants.

Q: Is it current or superseded?

A: The designation C661‑15 is the 2015 approved version; it was reapproved/republished in 2022 and is listed as active (C0661‑15R22 / C661‑15(2022)). Users should reference the reapproved 2022 listing for the current active text.

Q: Is it part of a series?

A: It is developed and maintained by ASTM Committee C24 (sealants) and is part of the C24 family of standards covering sealant specifications and test methods; it is often used alongside specifications such as ASTM C920 and other test methods for sealant properties.

Q: What are the key keywords?

A: Indentation hardness, durometer, elastomeric sealant, Shore A, Shore 00, joint sealant, building construction, quality control.