30 real HAZOP & Process Safety questions from the Process Design bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is HAZOP node?
Junior
A.independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response
B.semi-quantitative method multiplying initiating event frequency by the probability of failure on demand of each independent protection layer against a tolerable frequency target
C.standard deviation prompts No, More, Less, Reverse, Part of, As well as and Other than, combined with parameters like flow, pressure, temperature and level
D.section of the P&ID such as a line or vessel with a defined design intent, to which guidewords are applied one parameter at a time
2. Which term means: "section of the P&ID such as a line or vessel with a defined design intent, to which guidewords are applied one parameter at a time"?
A.HAZOP node — standard deviation prompts No, More, Less, Reverse, Part of, As well as and Other than, combined with parameters like flow, pressure, temperature and level
B.HAZOP node — section of the P&ID such as a line or vessel with a defined design intent, to which guidewords are applied one parameter at a time
C.HAZOP node — quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
D.HAZOP node — vapour generated by the API 521 heat input Q = 21000·F·A^0.82 (US units) over wetted area up to 25 ft above grade, with F reduced by insulation or drainage
A.overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion
B.relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
C.quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
D.standard deviation prompts No, More, Less, Reverse, Part of, As well as and Other than, combined with parameters like flow, pressure, temperature and level
5. Which term means: "standard deviation prompts No, More, Less, Reverse, Part of, As well as and Other than, combined with parameters like flow, pressure, temperature and level"?
A.HAZOP guidewords — standard deviation prompts No, More, Less, Reverse, Part of, As well as and Other than, combined with parameters like flow, pressure, temperature and level
B.HAZOP guidewords — section of the P&ID such as a line or vessel with a defined design intent, to which guidewords are applied one parameter at a time
C.HAZOP guidewords — safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511
D.HAZOP guidewords — independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response
A.independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response
B.relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
C.safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511
D.quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
8. Which term means: "independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response"?
A.Layers of protection — quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
B.Layers of protection — independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response
C.Layers of protection — semi-quantitative method multiplying initiating event frequency by the probability of failure on demand of each independent protection layer against a tolerable frequency target
D.Layers of protection — safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511
A.standard deviation prompts No, More, Less, Reverse, Part of, As well as and Other than, combined with parameters like flow, pressure, temperature and level
B.semi-quantitative method multiplying initiating event frequency by the probability of failure on demand of each independent protection layer against a tolerable frequency target
C.Fire and Explosion Index that scores a material factor with general and special process hazards to rank units and set spacing and protection
D.independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response
11. Which term means: "semi-quantitative method multiplying initiating event frequency by the probability of failure on demand of each independent protection layer against a tolerable frequency target"?
A.LOPA — quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
B.LOPA — independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response
C.LOPA — overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion
D.LOPA — semi-quantitative method multiplying initiating event frequency by the probability of failure on demand of each independent protection layer against a tolerable frequency target
A.standard deviation prompts No, More, Less, Reverse, Part of, As well as and Other than, combined with parameters like flow, pressure, temperature and level
B.independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response
C.relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
D.safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511
14. Which term means: "safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511"?
A.SIL — overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion
B.SIL — relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
C.SIL — safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511
D.SIL — section of the P&ID such as a line or vessel with a defined design intent, to which guidewords are applied one parameter at a time
A.relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
B.quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
C.section of the P&ID such as a line or vessel with a defined design intent, to which guidewords are applied one parameter at a time
D.vapour generated by the API 521 heat input Q = 21000·F·A^0.82 (US units) over wetted area up to 25 ft above grade, with F reduced by insulation or drainage
17. Which term means: "relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow"?
A.API 520 PSV sizing — relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
B.API 520 PSV sizing — Fire and Explosion Index that scores a material factor with general and special process hazards to rank units and set spacing and protection
C.API 520 PSV sizing — independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response
D.API 520 PSV sizing — standard deviation prompts No, More, Less, Reverse, Part of, As well as and Other than, combined with parameters like flow, pressure, temperature and level
A.overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion
B.semi-quantitative method multiplying initiating event frequency by the probability of failure on demand of each independent protection layer against a tolerable frequency target
C.relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
D.independent safeguards in order: process design, BPCS, alarms and operator, SIS, relief devices, physical containment and emergency response
20. Which term means: "overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion"?
A.API 521 relief scenarios — safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511
B.API 521 relief scenarios — vapour generated by the API 521 heat input Q = 21000·F·A^0.82 (US units) over wetted area up to 25 ft above grade, with F reduced by insulation or drainage
C.API 521 relief scenarios — overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion
D.API 521 relief scenarios — quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
A.quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
B.semi-quantitative method multiplying initiating event frequency by the probability of failure on demand of each independent protection layer against a tolerable frequency target
C.vapour generated by the API 521 heat input Q = 21000·F·A^0.82 (US units) over wetted area up to 25 ft above grade, with F reduced by insulation or drainage
D.overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion
23. Which term means: "vapour generated by the API 521 heat input Q = 21000·F·A^0.82 (US units) over wetted area up to 25 ft above grade, with F reduced by insulation or drainage"?
A.Fire case relief load — overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion
B.Fire case relief load — relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
C.Fire case relief load — vapour generated by the API 521 heat input Q = 21000·F·A^0.82 (US units) over wetted area up to 25 ft above grade, with F reduced by insulation or drainage
D.Fire case relief load — safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511
A.relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
B.Fire and Explosion Index that scores a material factor with general and special process hazards to rank units and set spacing and protection
C.section of the P&ID such as a line or vessel with a defined design intent, to which guidewords are applied one parameter at a time
D.quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
26. Which term means: "Fire and Explosion Index that scores a material factor with general and special process hazards to rank units and set spacing and protection"?
A.Dow F&EI — relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
B.Dow F&EI — safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511
C.Dow F&EI — section of the P&ID such as a line or vessel with a defined design intent, to which guidewords are applied one parameter at a time
D.Dow F&EI — Fire and Explosion Index that scores a material factor with general and special process hazards to rank units and set spacing and protection
A.standard deviation prompts No, More, Less, Reverse, Part of, As well as and Other than, combined with parameters like flow, pressure, temperature and level
B.semi-quantitative method multiplying initiating event frequency by the probability of failure on demand of each independent protection layer against a tolerable frequency target
C.overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion
D.quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
29. Which term means: "quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours"?
A.QRA — overpressure causes to be evaluated: blocked outlet, external fire, cooling failure, control valve failure, tube rupture and thermal expansion
B.QRA — relief valve orifice area computed from required relief rate, set pressure, back pressure and fluid properties for vapour, liquid or two-phase flow
C.QRA — quantitative risk assessment combining release frequencies with consequence modelling of dispersion, fire and explosion to produce individual and societal risk contours
D.QRA — safety integrity level 1 to 4 defining probability-of-failure-on-demand bands; SIL 2 needs PFD between 10⁻³ and 10⁻² under IEC 61511
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