Q1.

Outline the operational control measures that could minimise the risk of plant damage or
injury during start-up and shutdown of a process.
 Control system — process controls- intelligent alarms
 Suitable procedures and methods
 Trained and competent employees
 Suitable supervision of the operation
 Detection systems- flow/ no flow/ overflow
 Zone controls
 Use of flares / over flow / over pressure devices
 Maintenance and integrity of systems

Q2. a) Outline the types of failure mode of storage tanks that may lead to loss of
containment from hydrocarbon.
 Effect of Vacuum during emptying of tank
 Overload of foundations
 Overfilling
 Corrosion
 Operator / Instrument Error
 Bund Failure
 Poor design
 Tank not tested
 Poor construction

b) Identify the controls available to maintain Safety Critical Equipment

 Process Control Systems
 Process and Emergency Shut down systems
 Fire and Gas Systems
 Drilling Control systems

Q3. Dring an inspection an external fuel storage tank is found without a bund.
a) Identify TWO reasons for providing a tank bund.
 Prevent a potential leak causing environmental damage
 Control any leak within an known area
 Ensure the maximum quantity of product can be contained within the bund

b) Outline the features which should be included in the design of a tank bund.
 Ensure the maximum quantity of product can be contained within the bund at least
110%
 Located away from traffic routes
 Impermeable base
 No drain valve- rain water should be pumped out
 Lightening protection

Q.4 Large quantities of hydrocarbons are contained in a process plant, with the risk of gas
release and explosions.
(a) Identify THREE types of fire or explosion that could occur.
   "BLEVE" Boiling Liquid Evaporating Vapor Explosion"
  CVCE's Explosion of a liquefied hydrocarbon in a confined space
  UVCE's When Hydrocarbon air mixture an ignition source

(b) Identify process safety control measures that would minimise the risk
of an explosion.
 Passive Fire Protection systems
 Structural Fire Protection systems•
 Fire Detection Systems — Heat detectors; Flame detectors; Smoke detectors; Duct
Sampling; Acoustic detectors
 Gas detectors
 Zoning
 Process safety systems and controls; flares and vents;

(c) Identify the zone classifications relating to flammable atmospheres.

 Zone 0- Area where an explosive gas atmosphere is present continuosly or for long
periods
 Zone 1- Area where an explosive atmosphere is likely to occur in normal
operations
 Zone 2- Area where an explosive atmosphere is not likely to occur in normal
operations — if it occurs will only exist for a short time

Q5. (a) Outline the actions that should be taken by a person upon discovering a fire.
 Call emergency services
 Call Alarm
 Isolate any gas/ hydrocarbon supplies if possible
 Evacuate area

(b) Identify different ways in which an alarm may be raised in the event of a fire in a building.
 Manually
 Automatically
 Visually
 Verbally

Q6. Identify suitable control measures to minimise the risk to employees using mechanical
land transport.
 Suitable working hours — rest periods
 Suitable maintenance of vehicles
 Maintain speed limits
 Wear Seat belts
 Correct loads and security of loads
 Chemical and Hazardous material controls
 Training of drivers
 Traffic routes and plans

Q7. Outline how a Boiling Liquid Expanding Vapour Explosion (BLEVE) occurs.
"BLEVE" is an acronym for "Boiling Liquid Evaporating Vapor Explosion" and involves a
situation where. a liquid in a container -- often a compressed liquid such are propane --
suddenly fails, resulting in a rapid expansion of the liquid into a vapor, releasing energy that
is capable of hurtling parts of the tank or other nearby objects for considerable distances. If an
ignition source is present and the vapor is flammable, a sudden deflagration (fire) or
explosion may occur, further increasing the energy of the sudden vapor release, and causing
the creation of a fireball that releases a sudden burst of radiant (heat) energy. The largest
documented BLEVE explosions (usually involving propane or similar substances) have
resulted in numerous deaths, some at great distances from the initial explosion (hundreds of
feet or more) from either propulsion of debris, exposure to radiant heat, or a combination of
both.

Q8 (a) Identify the hazardous properties of Liquid Petroleum Gas (LPG).

 Heavier than air
 Vaporisation - Cold
 Storage — Leaks
 Fire / Explosion

(b) Outline the risks associated with Liquid Petroleum gas (LPG).
 Asphyxiation
 Bums (Hot and Cold)
 Fire / Explosion

Q9 Outline the following failure modes that may lead to loss of hydrocarbon containment
from storage tanks/vessels or pipelines:
(a) creep;
 creep — is slow movement under stress, made more severe with heat for long
periods, especially with increases in temperature approaching melting points.

-(b) stress corrosion cracking;

 stress corrosion — occurs under tensile stress and is worse in a corrosive
environment at elevated temperatures.

(c) thermal shock;

 thermal shock — cracking associated with rapid temperature change and different
parts of an object expanding at different parts where the stress overcomes the
strength of the materials.

(d) brittle fracture.

 brittle fracture — rapid run of cracks through a stressed material with plastic
deformation before failure caused by such things as repetition of inappropriate
heating or pressurising rates.

Q10 A large oil company is proposing to build a new oil and gas installation in the North Sea.
The Process Safety Management Team is analysing past incidents and database records from
the Oil and Gas Industry.
Excluding active and passive fire protection systems, outline physical design features of the
platform that would minimise risk to operating personnel in the event of a major incident
 Plant separation
 Compartmentalisation
 Protection of personnel / equipment
 Means of escape
 Blow out panels
 Temporary refuges (communications) & (control)

Q11 An operator is draining a flammable liquid from process pipework to a metal container.
The supervisor is concerned about the possibility of an electrostatic charge forming and stops
this operation until a risk assessment is undertaken. During this work activity:
(a) Identify factors that influences the generation of the electrostatic charge;
 Lack of earthing / bonding
 Air temperature
 Humidity
 Overfilling
 Liquid volatility

(b),Outline practical ways of minimising the formation of an electrostatic charge.

 Antistatic additives
 Reduce velocity
 Intrinsically safe equipment

Q12 Outline physical design features of an oil and gas installation that would minimise risk to
operating personnel in the event of a major incident.
 Temporary Refuge
 Routes to and from the TR
 Means of evacuation from these points
 Facilities within the TR for monitoring and control of the incident and organizing
evacuation

Q13 An operator is draining a flammable liquid from process pipe work to a metal container.
The supervisor is concerned about the possibility of an electrostatic charge forming and stops
this operation until a risk assessment is undertaken.
During this work activity:
(a) Identify factors that influence the generation of the electrostatic charge;
 Temperature
 Pressure Velocity
 Flammable atmosphere
 Conductivity of materials

(b) Outline practical ways of minimizing the formation of an electrostatic charge.

 Effective grounding of conductors
 Use of low or non conductive materials
 Reduce temperature, pressure and velocity
Remove flammable atmosphere
Q14 (a) Petroleum storage tank fires have been reduced substantially by using floating
roofs, but a fire risk may still exist.
(i) Outline how a fire risk may exist with floating tanks.
 Lightning strikes
 Leaks due to corrosion, damaged pipe work
 Product overfill or high internal pressures
 Rainwater or snow load sinks the roof and exposes fuel vapours

(ii) Identify TWO examples of fire protection systems used on floating roof tanks.
 Fixed foam systems
 Portable foam fire fighting systems
 Hose lines

(b) Process modules in an oil and gas installation often contain computer rooms that
require fire protection
Identify TWO examples of fire extinguishing media that could be used in a computer room.
 Carbon Dioxide
 FM200 — DuPont
 Halon - Being phased out — Montreal Protocol 1987 Novec 1230 — 3M Halon
replacement product

Q15 During an inspection an external fuel storage tank is found without a bund wall:
(a) Identify the environmental effects if a tank failure occurred;
 Oil contamination of ground would be highly toxic to plant and animal life and
could enter rivers and waterways depriving life of oxygen

(b) Outline the features which should be included in the design of a tank bund wall.
 Base has to be impermeable to water and oil
 Able to store 110% of one tank and 25% of total storage
 No drainage valve should be incorporated
 Valves, sight gauge, filter, vent pipe and ancillary equipment must be kept within
the bund when not in use