NEBOSH HSE PSM ACTUAL 2026 EXAM QUESTIONS AND
SOLUTIONS RATED A+
✔✔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.
✔✔Typical uses of Inert Gases (chemically inactive gases): - ✔✔Inerting equipment to
prevent flammable atmospheres.
Preparing equipment for maintenance by purging out hydrocarbons.
Removing air/oxygen in equipment before start-up.
Blanketing tanks to prevent the ingress of air to avoid flammable atmospheres in the
headspace.
Pressure control blanketing-nitrogen introduced into the tank headspace to maintain a
set pressure.
Certain welding operations.
Decommissioning equipment to prevent the rusting process.
Instrument air backup.
, ✔✔Use of Inert gases as fire fighting agents - ✔✔Typically CO2 is used for this purpose
in domestic and office areas and on some plant. For major industrial use and process
plants, a mixture of gases may be preferred. A typical mixture is 52% nitrogen, 40%
argon, 8% carbon dioxide.
✔✔Types of tanks used to store liquids - ✔✔Fixed-roof tanks (atmospheric tanks).
External floating roof tanks.
Internal floating roof tanks.
Domed external floating roof tanks.
Horizontal tanks.
Pressure tanks.
Variable vapour space tanks.
Liquified Natural Gas (LNG) tanks.
✔✔Creep - ✔✔Describes the gradual extension of material under a steady tensile
stress over a long period of time, particularly in high temperatura conditions.
✔✔Stress - ✔✔Refers to the tensile or compressive loading placed on the material.
(Stress corrosión and hydrogen embrittlement).
✔✔Thermal Shock - ✔✔Results form exposing materials to rapid and extreme
temperatura changes.
✔✔Brittle Fracture - ✔✔Occur suddenly when the material is put under excesive stress
and has no, or limited, elasticity.
✔✔Fatigue Failure - ✔✔Fatigue is the formation of cracks as a result of repeated
application of loads that individually do not create sufficient stress to cause failure:
Thermal fatigue.
Contact fatigue.
Surface or pitting fatigue.
Subsurface cracking or subsurface fatigue.
Corrosion fatigue.
✔✔Protection of Tanks from Extremes of Weather - ✔✔Tanks may need to be protected
from extremes of weather. In both hot and cold climates, the tank will be exposed to
wide variations in temperature. If this is assessed as an issue, the tank can be
insulated. High wind loadings may also affect the tank by causing distortions and
uplifting from the base.
Distortion can be limited by girding the tank with metal bands.
Trace heating may need to be provided on pipework for some materials.
✔✔The Triangle of Fire: - ✔✔Heat.
SOLUTIONS RATED A+
✔✔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.
✔✔Typical uses of Inert Gases (chemically inactive gases): - ✔✔Inerting equipment to
prevent flammable atmospheres.
Preparing equipment for maintenance by purging out hydrocarbons.
Removing air/oxygen in equipment before start-up.
Blanketing tanks to prevent the ingress of air to avoid flammable atmospheres in the
headspace.
Pressure control blanketing-nitrogen introduced into the tank headspace to maintain a
set pressure.
Certain welding operations.
Decommissioning equipment to prevent the rusting process.
Instrument air backup.
, ✔✔Use of Inert gases as fire fighting agents - ✔✔Typically CO2 is used for this purpose
in domestic and office areas and on some plant. For major industrial use and process
plants, a mixture of gases may be preferred. A typical mixture is 52% nitrogen, 40%
argon, 8% carbon dioxide.
✔✔Types of tanks used to store liquids - ✔✔Fixed-roof tanks (atmospheric tanks).
External floating roof tanks.
Internal floating roof tanks.
Domed external floating roof tanks.
Horizontal tanks.
Pressure tanks.
Variable vapour space tanks.
Liquified Natural Gas (LNG) tanks.
✔✔Creep - ✔✔Describes the gradual extension of material under a steady tensile
stress over a long period of time, particularly in high temperatura conditions.
✔✔Stress - ✔✔Refers to the tensile or compressive loading placed on the material.
(Stress corrosión and hydrogen embrittlement).
✔✔Thermal Shock - ✔✔Results form exposing materials to rapid and extreme
temperatura changes.
✔✔Brittle Fracture - ✔✔Occur suddenly when the material is put under excesive stress
and has no, or limited, elasticity.
✔✔Fatigue Failure - ✔✔Fatigue is the formation of cracks as a result of repeated
application of loads that individually do not create sufficient stress to cause failure:
Thermal fatigue.
Contact fatigue.
Surface or pitting fatigue.
Subsurface cracking or subsurface fatigue.
Corrosion fatigue.
✔✔Protection of Tanks from Extremes of Weather - ✔✔Tanks may need to be protected
from extremes of weather. In both hot and cold climates, the tank will be exposed to
wide variations in temperature. If this is assessed as an issue, the tank can be
insulated. High wind loadings may also affect the tank by causing distortions and
uplifting from the base.
Distortion can be limited by girding the tank with metal bands.
Trace heating may need to be provided on pipework for some materials.
✔✔The Triangle of Fire: - ✔✔Heat.
