ASTM D1056 – Standard Specification for Flexible Cellular Materials—Sponge or Expanded Rubber
This specification covers flexible cellular rubber products known as sponge rubber and expanded rubber, but does not apply to latex foam rubber or ebonite cellular rubber. The base material for an open/closed cellular product may be made of synthetic, natural, or reclaimed rubber, or a mixture, and may contain other polymers or chemicals, or both, which may be modified by organic or inorganic additives. The cellular rubber shall be categorized by types, classes, grades, and suffixes: Types 1 and 2; Classes A, B, C, and D; Grades 0, 1, 2, 3, 4, and 5. The various grades of cellular rubber shall conform to the requirements as to physical properties specified. The following test methods shall be performed: accelerated aging tests; compression-deflection tests; oil-immersion test (open-cell sponge); fluid immersion tests (closed cell); water absorption test; density tests; and low-temperature flex test.
ASTM D1056 Cellular Materials Classification Chart
| Type | Class | Grade Number kPa(psi) required to deflect a sample 25% of its height. |
Suffix Requirements Suffix letters are used to indicate the tests met by the compounds. In a line callout, the numbers following the suffix letters indicate test parameters or the particular conditions related to the suffix. |
| Type 1 =
open cell
Type 2 = closed cell |
Class A = non oil‑resistant
(e.g. EPDM) Class B = oil-resistant, low oil swelling (e.g. Nitrile) Class C = oil-resistant, medium oil swelling (e.g. Neoprene) Class D = resistant to extreme temperatures (e.g. Silicone) |
Grade 0 = less than 15 (2)
Grade 1 = 15 to 35 (2 to 5) Grade 2 = 35 to 65 (5-9) Grade 3 = 65 to 90 (9-13) Grade 4 = 90 to 120 (13-17) Grade 5 = 120 to 170 (17-25) |
A = Heat Resistance B = Compression Set C = Ozone or Weather Resistance D = Compression-Deflection Resistance E = Fluid Resistance F = Low Temperature Resistance G = Tear Resistance J = Abrasion Resistance K = Adhesion L = Water Absorption M = Flammability Resistance N = Impact Resistance P = Staining Resistance R = Resilience W = Density Z = Special Requirements |