"GB/T 28799.4-2024 Heat-resistant polyethylene (PE) (PE-RT) piping systems for hot and cold water, Part 4: Valves" specifies the material, classification, type, size and deviation, physical and mechanical properties requirements, inspection rules, marking, Encasement, transportation and storage requirements for heat-resistant polyethylene (PE) valves for hot and cold water piping systems, and describes the corresponding test methods in detail. This standard applies to valves made of PE-RT type I materials, including ball valves with nominal dimensions greater than 400 mm. This standard and the Miscellaneous part of GB/T 28799 are jointly applicable to various types of hot and cold water piping systems, including domestic hot and cold water, drinking water, heating systems in civil and industrial buildings, as well as hot spring water piping systems and central heating secondary pipe network systems.