关键词: 安全仪表功能, 冗余架构, 安全失效因子, 平均失效率, 误停车率, 共因失效, 检验测试时间间隔, 仪表故障模式

Abstract: The redundant architecture of the safety instrumented function(SIF) loop should meet the requirement of safety and spurious trip rate(STR). Combining the experience on safety integrity level(SIL) verification, an engineering analysis is conducted on the standards and various mandatory constraints that affect the design of SIF redundant architecture, as well as the factors that affect the design of SIF loop redundant architecture, such as safety failure factor(SFF), mean failure rate, spurious trip rate, common cause failure(CCF), proof test interval, instrument measuring and manufacturing principle, constraints of instrument failure mode on redundant architecture degradation. Suitable redundant architecture design philosophies have been provided. A suitable redundant architecture design should include all components in the SIF loop. More instruments do not mean better neither do less instruments. If the economical condition permits, rationality should be the result of balancing safety and low spurious trip rate.

Key words: safety instrumented function(SIF), redundant architecture, safety failure factor(SFF), mean failure rate, spurious trip rate(STR), common cause failure(CCF), proof test interval, instrument failure mode