HAZOP-Update, SIL-Verification for Compressor Station Legacy Systems
Projectowner:
Confidential
Timeframe:
2017 – 2018
Key Project Data:
Existing gas transport compressor station, in operation since ca. 10 years, comprising:
- Electric-motor-driven (EM) gas compressor
- Gas-turbine-driven (GT) gas compressor
- Pipeline interconnections, including metering stations
- Tie-in of new pipeline and over-pressure protection systems (under construction 2018)
- Existing station auxiliary and utility systems, including three independent legacy safety systems (Station, EM-compressor, GT-compressor)
Scope of Services:
- Update of HRA (re-HAZOP) and SIL-analysis (Risk Graph method acc. VDI/VDE 2180)
- Gap analysis of existing FSM-documentation
- Preparation of Cause & Effect Chart for safety and process trip logic
- Investigations on site to confirm as-built status of safety-related loops
- SIL-Verification using ExSILentia and preparation of compliance report (equivalent to FSA-4) according to DIN EN 61511:2012
- Preparation of recommendations and priorities for implementation
All services were carried out in accordance with PSC’s FSM-Plan as per DIN EN 61511 and CFSE-certified.
Extended Description
The following gives a detailed description of PSC‘s services.
Existing safety review was updated on basis of as-built status. The update was carried out via several workshops covering following nodes:
- Station main process systems
- Station auxiliary systems (vent, fuel gas, fire & gas system)
- Flow path variations (ca. 50 station operating modes investigated)
- Compressor-driver units, including auxiliaries
- Tie-in of new pipeline and over-pressure protections
SIL / Risk reduction analysis carried out as per calibrated Risk Graph methodology (VDI/VDE 2180). 70 safety loops investigated, resulting in definition of SIL/RRF for 34 SIFs.
Review of legacy documentation established that some FSM-documents should be updated, e.g.
- Cause & Effect Chart
- Safety Requirements Specification
- Sensor / actor failure data/ certification
Modelling of SIFs using ExSILentia software
- Review of available E&I, safety system logic and vendor documentation and confirmation of ‘as-built’ status via site inspections
- Database research / contact to manufacturers to establish failure data for legacy equipment with missing certification
- Evaluation of ‘proven-in-use’ capability where published failure data was not available
- Review of site proof-test procedures in order to define CPT for all SIFs
- Modelling of loops in ExSILentia and preparation of compliance documentation
- Recommendations based on identification of FSM-compliance issues:
- SIL-degradation
- End of equipment useful life
- Proof test coverage
- Management of non-SIL functions implemented in safety systems