Abstract

The proper flare stack design becomes a big issue after refinery plant explosion accident in USA in 2005. API 521 was upgraded several times for better flare stack design after 2005. Safety Instrumented Level (SIL) 3 High Integrity Protection System (HIPS) is important equipment to reduce flare load capacity according to API 521. Korea government reviewed and approved the flare stack design from 2005 based on API 521, but Korea government started to require stricter supplementation based on IEC 61511 than API 521 after flare stack overload incident in 2017. Even though SIL 3 HIPS plays an important role to prevent flare stack overload while the flare stack capacity is below maximum flare load, Korea government require HAZOP report, LOPA report, Safety Requirement Specification (SRS), SIL verification report and Functional Safety Management System (FSMS) to keep SIL 3 properly during HIPS lifecycle.

Keywords:Flare stack; API 521; IEC 61511; SIL; HIPS

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