NEBOSH PSM ANSWERS AND QUESTIONS SET A+
✔✔Acronym: uninterruptible power supply - ✔✔Acronym: UPS
✔✔Uninterruptible power supply (UPS) - ✔✔A temporary back-up power supply
installed between main power supply and critical equipment
✔✔Battery powered - ✔✔How do UPS' usually function?
✔✔alarm to alert workers to the power outage - ✔✔What function additional to providing
uninterruptible power to critical equipment might a UPS have?
✔✔Acronym: Probability of failure on demand - ✔✔Acronym: PFD
✔✔Probability of failure on demand (PFD) - ✔✔the probability that a component will fail
to perform its safety function at the time it is needed
✔✔Answer: Probability of failure on demand (PFD) - ✔✔In what terms is the 'reliability'
measure of FARSI often expressed?
✔✔Acronym: Mean Time Between Failure - ✔✔Acronym: MTBF
✔✔Mean Time Between Failures (MTBF) - ✔✔The calculated average time that elapses
between failures of a system, equipment or a component.
✔✔Answer: Mean time between failures (MTBF) - ✔✔What is the measure used in
relation to predicted failures of repairable systems?
✔✔Acronym: Safety instrumented system - ✔✔Acronym: SIS
✔✔Safety Instrumented System (SIS) - ✔✔An instrumented system used to implement
either a safety control or protection function (or both)
, ✔✔Sensor(s), logic solver(s) and final element(s) - ✔✔What three connected
components make up a SIS?
✔✔logic solver - ✔✔Which component of a SIS decides what action to take depending
on the sensor input
✔✔Final element - ✔✔Which component of a SIS carries out the physical action (e.g.
valve)?
✔✔Acronym: Safety integrity level - ✔✔Acronym: SIL
✔✔Safety Integrity Level (SIL) - ✔✔The specified levels of safety integrity a SIS needs
to have
✔✔Level 1 (lowest) to Level 4 (highest) - ✔✔What are the levels of the SIL system?
✔✔Safety integrity of SIS - ✔✔The average probability of a SIS performing its function
(under stated conditions for a certain period of time)
✔✔Saturated steam - ✔✔Steam that is still wet
✔✔3-5% - ✔✔What percentage of water remains in saturated steam?
✔✔Superheated steam - ✔✔Steam with temperature higher than its boiling point
✔✔Answer: Superheated steam - ✔✔Which type of steam is invisible?
✔✔Vacuum steam - ✔✔Steam created by reducing the operation pressure using a
vacuum pump, so the steam effectively below 100degs
✔✔Thermal expansion - ✔✔Hazard created by the expansion of pipelines or vessel as
a result of steam exposure
✔✔Answer: Thermal expansion - ✔✔What type of hazard is prevented by building in
flexibility or using bellows etc to allow material to expand?
✔✔Vacuum formation from steam - ✔✔Hazard created by steam producing
condensate, resulting in decreased volume
✔✔Vacuum breakers - ✔✔What measure is important to ensure there is sufficient
pressure within a system using steam to allow the condensate to be discharged?
✔✔Water Hammer - ✔✔Hazard resulting from water in a pipeline striking a fixed object
under high pressure
✔✔Acronym: uninterruptible power supply - ✔✔Acronym: UPS
✔✔Uninterruptible power supply (UPS) - ✔✔A temporary back-up power supply
installed between main power supply and critical equipment
✔✔Battery powered - ✔✔How do UPS' usually function?
✔✔alarm to alert workers to the power outage - ✔✔What function additional to providing
uninterruptible power to critical equipment might a UPS have?
✔✔Acronym: Probability of failure on demand - ✔✔Acronym: PFD
✔✔Probability of failure on demand (PFD) - ✔✔the probability that a component will fail
to perform its safety function at the time it is needed
✔✔Answer: Probability of failure on demand (PFD) - ✔✔In what terms is the 'reliability'
measure of FARSI often expressed?
✔✔Acronym: Mean Time Between Failure - ✔✔Acronym: MTBF
✔✔Mean Time Between Failures (MTBF) - ✔✔The calculated average time that elapses
between failures of a system, equipment or a component.
✔✔Answer: Mean time between failures (MTBF) - ✔✔What is the measure used in
relation to predicted failures of repairable systems?
✔✔Acronym: Safety instrumented system - ✔✔Acronym: SIS
✔✔Safety Instrumented System (SIS) - ✔✔An instrumented system used to implement
either a safety control or protection function (or both)
, ✔✔Sensor(s), logic solver(s) and final element(s) - ✔✔What three connected
components make up a SIS?
✔✔logic solver - ✔✔Which component of a SIS decides what action to take depending
on the sensor input
✔✔Final element - ✔✔Which component of a SIS carries out the physical action (e.g.
valve)?
✔✔Acronym: Safety integrity level - ✔✔Acronym: SIL
✔✔Safety Integrity Level (SIL) - ✔✔The specified levels of safety integrity a SIS needs
to have
✔✔Level 1 (lowest) to Level 4 (highest) - ✔✔What are the levels of the SIL system?
✔✔Safety integrity of SIS - ✔✔The average probability of a SIS performing its function
(under stated conditions for a certain period of time)
✔✔Saturated steam - ✔✔Steam that is still wet
✔✔3-5% - ✔✔What percentage of water remains in saturated steam?
✔✔Superheated steam - ✔✔Steam with temperature higher than its boiling point
✔✔Answer: Superheated steam - ✔✔Which type of steam is invisible?
✔✔Vacuum steam - ✔✔Steam created by reducing the operation pressure using a
vacuum pump, so the steam effectively below 100degs
✔✔Thermal expansion - ✔✔Hazard created by the expansion of pipelines or vessel as
a result of steam exposure
✔✔Answer: Thermal expansion - ✔✔What type of hazard is prevented by building in
flexibility or using bellows etc to allow material to expand?
✔✔Vacuum formation from steam - ✔✔Hazard created by steam producing
condensate, resulting in decreased volume
✔✔Vacuum breakers - ✔✔What measure is important to ensure there is sufficient
pressure within a system using steam to allow the condensate to be discharged?
✔✔Water Hammer - ✔✔Hazard resulting from water in a pipeline striking a fixed object
under high pressure
