NEBOSH PSM UPDATED 2027 SETS ANSWERS AND
QUESTIONS SET A+
✔✔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.
Oxygen.
Fuel.
✔✔Mechanisms of Heat Transfer: - ✔✔Conduction.
Convection.
Radiation.
✔✔Typical ignition sources - ✔✔Smoking.
Sparking.
Naked flames.
Electrical discharges.
Hot surfaces.
Mechanical friction.
Lighting.
✔✔Zoning/hazardous area classification - ✔✔For flamable vapors:
Zone 0: A place in which an explosive atmosphere is present continously.
Zone 1: A place in which an explosive atmosphere is likely to occur.
Zone 2: A place in which and explosive atmosphere is not likely to occur in normal
operation.
For flammable dusts: An explosive atmosphere in the form of a cloud of combustible
dust in air: Zone 20, Zone 21, Zone 22.
✔✔Conditions for dust to become explosive - ✔✔Particle size.
Dispersal.
Explosive concentrations. Dust has indicative values like LEL 25-50 g per cubic meter
and UEL ten times the LEL.
Ignition energy.
QUESTIONS SET A+
✔✔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.
Oxygen.
Fuel.
✔✔Mechanisms of Heat Transfer: - ✔✔Conduction.
Convection.
Radiation.
✔✔Typical ignition sources - ✔✔Smoking.
Sparking.
Naked flames.
Electrical discharges.
Hot surfaces.
Mechanical friction.
Lighting.
✔✔Zoning/hazardous area classification - ✔✔For flamable vapors:
Zone 0: A place in which an explosive atmosphere is present continously.
Zone 1: A place in which an explosive atmosphere is likely to occur.
Zone 2: A place in which and explosive atmosphere is not likely to occur in normal
operation.
For flammable dusts: An explosive atmosphere in the form of a cloud of combustible
dust in air: Zone 20, Zone 21, Zone 22.
✔✔Conditions for dust to become explosive - ✔✔Particle size.
Dispersal.
Explosive concentrations. Dust has indicative values like LEL 25-50 g per cubic meter
and UEL ten times the LEL.
Ignition energy.
