This document specifies the terms and definitions, abbreviations, system overview, working environment conditions, basic requirements, technical requirements, test methods, inspection rules, marking, packaging, transportation and storage, and quality commitments and services of the safety instrumented system. This document is applicable to safety instrument systems used in process industries in petrochemical, oil and gas, chemical, nuclear power, thermal power and other industries. It can be used in emergency shutdown, fire and gas detection, burner management and other application scenarios.