The ASTM D4637-2021 standard specification specifies requirements for ethylene propylene ternary rubber (EPDM) sheets for use in single-layer roofing membranes. The specification covers vulcanized rubber sheets that are not reinforced, fabric-reinforced, or fabric-backed, ensuring that their performance under exposure to weather conditions meets minimum mass standards. While the specification sets test and performance limits to be used to evaluate sheets, design criteria for roofing systems, such as fire resistance and material compatibility, are not specified in detail. The standard also states that all test values must use a single Measurement System and requires users to determine relevant safety and regulatory requirements before using the standard.