Element 3 - Causes And Prevention Of Fires And Explosions

Question 1

Sources of ignition of accidental fires

Answer 1

Electrical appliances and installations.
Lightning.
Cooking.
Heating and lighting.
Smoking.
Overheating of machinery.
Spontaneous combustion.
Hot work.

Question 2

Sources of fuel

Answer 2

Paper and cardboard.
Furniture, fixtures and fittings.
Electrical installations - pvc. 
Structural materials - timber
Piped gas supply.
Flammable gases in cylinders.
Flammable, chemicals, liquids and solvents.

Question 3

Sources of oxygen

Answer 3

Atmospheric air - 21% by volume
Natural ventilation.
Forced ventilation Systems - air con
Oxidising agents/ materials.

Question 4

Fire and explosion risks from flammable materials.

Common contributory factors are:

Answer 4

Operator error due to lack of awareness or training.
Hot work carried out on or close to flammable materials or flammable liquid containers.
Inadequate design or maintenance of equipment which fails.
Misuse of flammable liquids.
Inadequate control of ignition sources in inflammable liquid areas e.g. electrostatic discharge.
Allowing materials to be heated above the auto ignition temperature.
Dismantling disposing of equipment or containers containing flammable materials or their residues.
Inadequate containment e.g. leakage.
Failure to store incompatible materials properly.
Lack of control of transfer operations - decanting, spraying, spillages.

Question 5

Fire risks in construction and maintenance work

Answer 5

Site storage of flammable materials
Improper waste disposal
Demolition
Oxy fuel cutting equipment
Temporary electrical installations

Question 6

Factors influencing arson risk

Answer 6

Type of business e.g. controversial activities
Location of premises e.g. inner-city areas, isolated areas, areas of high crime.
Whether the area is undergoing redevelopment.

Question 7

VICES (flammable liquids storage)

Answer 7

Ventilation
Ignition
Containment
Exchange
Separation

Question 8

DSEAR hierarchy of control

Answer 8

Elimination
Control of risk
Mitigation of consequences
Safe handling, storage and transport
General safety measures e.g. safe systems of work.

Question 9

controlling sources of ignition

Answer 9

Using intrinsically safe equipment.
Controlling the use of mobile phones.
Maintenance and PAT testing.
Designated smoking areas.
Shielding to block radiant heat and sparks from hot work.
Fire risk assessments.

Question 10

Controlling sources of fuel

Answer 10

Segregating storage of incompatible substances.
Containment of leeks and spillages.
Precautions for filling and emptying containers.
Precaution for the transport of flammable materials e.g. loading and unloading, labelling, packaging and training.

Question 11

Controlling sources of oxygen

Answer 11

• Closing doors and windows to limit natural ventilation.
• Shutting off forced ventilation systems and associated ducting.
• Safe use and storage of oxidising materials

Question 12

Management of control measures

Answer 12

Implement safe systems of work.
Planned preventative maintenance programme.
Management of contractors.
Using permits to work.
Provision of information and training for employees.
General fire precautions during building maintenance and construction.
Prevention of arson.

Question 13

INDG297 Safety in Gas welding and cutting.

Safety precautions when using oxy fuel equipment.

Answer 13

• Train staff in the safe use of equipment and fire precautions.
• Using proper equipment e.g. pressure regulators, flashback arrestors, non-return valves.
• Follow a permit to work system to include: moving workpiece to safe location.
  Removing combustibles within 10 m of work.
  Ventilating with vapours may accumulate.
  Using guards/ covers to prevent hot particles.
  Firewatch for one hour afterwards.
  Fire extinguishers handy.
  Work is authorised by competent person and time-limited.

Question 14

Safe system of work

Answer 14

A formal procedure which results from systematic examination of a task in order to identify all the hazards. It defines safe methods to ensure that hazards are eliminated or risks minimised.

Question 15

Management of contractors

Answer 15

Select with care.
Should be competent and able to conduct the work safely.
Have been properly inducted onto site.
Subject to performance monitoring.

Question 16

Risks to maintaining fire protection systems during construction work

Answer 16

Detectors and sprinklers may be isolated.
Dismantling of walls may destroy integrity of compartment.
Fire escape routes may be blocked or rerouted.
Increase storage of combustible building materials.

Question 17

Provisions of information and training

Answer 17

Employees need:
Information on hazards and controls.
Training in safe systems of work and procedures.

Question 18

Actions to prevent arson attacks

Answer 18

• Perimeter fencing.
• CCTV.
• Intruder alarms.
• Floodlighting.
• Security guards.
• windows and doors locked outside normal working hours.
  Remove entry rights for persons who have been dismissed.
  Good standards of housekeeping.
  Combustibles, flammables and rubbish located away from buildings but not near boundary.
  Buffer zones between boundary and buildings.
  Fire protected letter boxes.

Question 19

Features of an external open-air storage location for flammable liquids

Answer 19

Secure, impervious, well ventilated, away from sources of ignition.
Sufficient separation from neighbouring buildings and boundaries:
- 2 metres up to 1000 litres.
- 4 metres up to 100000 litres.
7.5 metres over 100000 litres.

Question 20

Design features of an outdoor building used to store flammable liquids in drums

Answer 20

Single storey building
Constructed of non-combustible material.
Lightweight roof.
Adequate separation from other buildings.
Good ventilation at high and low levels.
Door sills to contain spillages.
No potential ignition sources. 
Fire extinguishing equipment nearby.
Appropriate signage.

Question 21

Measures to reduce the risk from storage of flammable liquids inside workplace

Answer 21

Maximum 50litres in work area.
More than 50 litres should be kept outside work place away from buildings.
Use metal containers with non spill cap.
Keep containers in a fire-resisting cabinet.
Store empty containers away from full ones.
Prevent ignition sources.
Provide appropriate fire fighting equipment.
Employees instructed in emergency procedures.

Question 22

Considerations for ANY flammable liquid storage facility.

Answer 22

Accessibility to firefighters.
Provisions of escape routes.
Fire fighting equipment (Incl sprinklers).
Proper signage.
Training for employees on hazards.