NEBOSH PSM EVALUATION 2027 ANSWERS AND
QUESTIONS SET A+
✔✔Safety Critical Element (SCE): - ✔✔Such parts of an installation and such of its plant
(including computer programs), or any part thereof the failure of which could cause or
contribute substantially to or a purpose is to prevent, or limit the effect of a major
incident.
✔✔Safety Instrumented System (SIS) - ✔✔This is an instrumented system used to
implement either a safety control or protection function (or both). An SIS is made of up
three connected parts: Sensor, Logic Solver and Final Element.
✔✔Safety Integrity Level (SIL). - ✔✔This is related to the concept of Safety Integrity,
which is the average probability of a SIS performing its function (under the stated
conditions for a required period of time).
✔✔Remotely Operated Shutoff Valve (ROSOV) - ✔✔A shutoff valve whose operation
can be controlled from a point which is remote from the valve itself, such as in a Control
Room. ROSOVs are mainly used for rapid emergency isolation of vessels, pipelines and
processes during emergencies, such as major leaks.
✔✔Emergency Shut-down (ESD). - ✔✔This is a safety system designed to operate
quickly to minimize consequences in the event of an emergency.
✔✔Definition of FARSI - ✔✔A model of performance standards for SCEs, which can be
described in terms of its:
Functionality.
Availability.
Reliability.
Survivability.
Interdependency.
✔✔Saturated Steam - ✔✔Saturated Steam or Wet Steam is produced at the boiling
point of water, at atmospheric pressure this is equivalent to 100 ⁰C. Between 3 and 5%
, of the water may be entrained in the steam. This reduces heating efficiency and also
can create problems for pipe work and reactor vessels. The condensate has to be
removed as near to the point of use as posible by steam traps.
✔✔Superheated Steam - ✔✔The superheated steam has a temperature higher than its
boilling point (for example 200 ⁰C) and it is more suited to transfer long distances
through pipework. It is an invisible gas and not readily detected by naked eye.
✔✔Vacuum Steam - ✔✔The vacuum steam is created by reducing the operation
pressure using a vacuum pump, so the steam effectively is below 100 ⁰C.
✔✔Steam injected into flare stacks - ✔✔Injecting steam into fluids atomices the fluid
and increases surface area. In the process industries, the steam is often injected into
flare stacks to improve combustion efficency and reduce emissions of pollutants.
✔✔Legionella Pneumophilia Bacteria - ✔✔This bacteria can survive when water
temperatures are in the range over 20 ⁰C and under 55 ⁰C. The ideal growth
temperature for the bacteria is 37 ⁰C (the human body temperature and hence the risk).
As well as causing pneumonia, the bacteria also can cause a fever (Pontiac fever) that
is generally less serious.
✔✔Catalysed and Uncatalysed Reaction - ✔✔A Catalyst is a medium put into a reaction
vessel that changes the pathway (mechanism)of a reaction
so the particles are forced into closer proximity. This increase the speed of a reaction by
lowering the
activation energy. Catalysts are not destroyed or changed during a reaction and are
generally reusable,
although they may suffer from poisoning by contamination with undesaired trace
substances in the reaction.
✔✔Measures to control and prevent a Run away chemical reaction - ✔✔Containment
within the reactor.
Crash cooling.
Drowning and quenching of reactor contents.
Emergency venting/ dumping of reactants.
✔✔Types of static charges - ✔✔Spark discharges.
Corona.
Brush.
Propagating brush.
Conical pile (Maurer).
Streaming current charge.
QUESTIONS SET A+
✔✔Safety Critical Element (SCE): - ✔✔Such parts of an installation and such of its plant
(including computer programs), or any part thereof the failure of which could cause or
contribute substantially to or a purpose is to prevent, or limit the effect of a major
incident.
✔✔Safety Instrumented System (SIS) - ✔✔This is an instrumented system used to
implement either a safety control or protection function (or both). An SIS is made of up
three connected parts: Sensor, Logic Solver and Final Element.
✔✔Safety Integrity Level (SIL). - ✔✔This is related to the concept of Safety Integrity,
which is the average probability of a SIS performing its function (under the stated
conditions for a required period of time).
✔✔Remotely Operated Shutoff Valve (ROSOV) - ✔✔A shutoff valve whose operation
can be controlled from a point which is remote from the valve itself, such as in a Control
Room. ROSOVs are mainly used for rapid emergency isolation of vessels, pipelines and
processes during emergencies, such as major leaks.
✔✔Emergency Shut-down (ESD). - ✔✔This is a safety system designed to operate
quickly to minimize consequences in the event of an emergency.
✔✔Definition of FARSI - ✔✔A model of performance standards for SCEs, which can be
described in terms of its:
Functionality.
Availability.
Reliability.
Survivability.
Interdependency.
✔✔Saturated Steam - ✔✔Saturated Steam or Wet Steam is produced at the boiling
point of water, at atmospheric pressure this is equivalent to 100 ⁰C. Between 3 and 5%
, of the water may be entrained in the steam. This reduces heating efficiency and also
can create problems for pipe work and reactor vessels. The condensate has to be
removed as near to the point of use as posible by steam traps.
✔✔Superheated Steam - ✔✔The superheated steam has a temperature higher than its
boilling point (for example 200 ⁰C) and it is more suited to transfer long distances
through pipework. It is an invisible gas and not readily detected by naked eye.
✔✔Vacuum Steam - ✔✔The vacuum steam is created by reducing the operation
pressure using a vacuum pump, so the steam effectively is below 100 ⁰C.
✔✔Steam injected into flare stacks - ✔✔Injecting steam into fluids atomices the fluid
and increases surface area. In the process industries, the steam is often injected into
flare stacks to improve combustion efficency and reduce emissions of pollutants.
✔✔Legionella Pneumophilia Bacteria - ✔✔This bacteria can survive when water
temperatures are in the range over 20 ⁰C and under 55 ⁰C. The ideal growth
temperature for the bacteria is 37 ⁰C (the human body temperature and hence the risk).
As well as causing pneumonia, the bacteria also can cause a fever (Pontiac fever) that
is generally less serious.
✔✔Catalysed and Uncatalysed Reaction - ✔✔A Catalyst is a medium put into a reaction
vessel that changes the pathway (mechanism)of a reaction
so the particles are forced into closer proximity. This increase the speed of a reaction by
lowering the
activation energy. Catalysts are not destroyed or changed during a reaction and are
generally reusable,
although they may suffer from poisoning by contamination with undesaired trace
substances in the reaction.
✔✔Measures to control and prevent a Run away chemical reaction - ✔✔Containment
within the reactor.
Crash cooling.
Drowning and quenching of reactor contents.
Emergency venting/ dumping of reactants.
✔✔Types of static charges - ✔✔Spark discharges.
Corona.
Brush.
Propagating brush.
Conical pile (Maurer).
Streaming current charge.
