Use of Quantitative Risk Assessment in Chemical Process IndustryJanuary 7, 2017
Integrity Verification Questionnaire for Corrosion Monitoring and Protection SystemApril 28, 2017
The objective of Pressure Relief system is to prevent overpressure leading to hazardous loss of containment by providing mechanical relief devices and disposal of the hazardous fluids through flare. During design and operational phases, the examination scheme for Pressure Relief would include following questions:
- Are Equipment and piping protected against overpressure by relief valves (RF)?
- Are Liquid lines, not continuously flowing and isolatable, protected by Thermal Relief Valves (TRVs)?
- Is discharge of all process relief devices directed through relief headers to flare?
- Are the operational locations of relief valves displayed on ‘Process Safeguarding Flow Schemes’?
- Are there any issues with sizing scenarios? What are the maximum relief pressures used during design?
- Do all relief valves on critical duty have installed spares with the same capacity and characteristics as the equipment in operation?
- Are suitable mechanical interlocks provided for valve changeover?
- Have the nitrogen plant relief valves been designed to vent to atmosphere at a ‘safe location’?
- Have liquid carryover scenarios identified and prevention controls in place?
- Does the system conform to API 521 recommended practice or equivalent?
- Are the pressure relief and venting facilities of low-pressure storage tanks (PVRV) including refrigerated storage, designed as per API RP 2000 or suitable standards?
- Are all Pressure Relief Valve isolations kept in open positions during normal operation?
- Are Hand Operation Levers set in no operation mode during normal operation?
- Have periodic checks been defined for inspecting leak through the rupture disk assembly or flanges?