2.6 Fire Safety

Question 1

What does the ILO emergency prevention require?

Answer 1

Emergency prevention, preparedness and response arrangements should be established and maintained. These arrangements should identify the potential for accidents and emergency situations, and address the prevention of OSH risks associated with them. The arrangements should be made according to the size and nature of activity of the organisation. They should:
• ensure that the necessary information, internal communication and coordination are provided to protect all people in the event of an emergency at the worksite;
• provide information to, and communication with, the relevant competent authorities, and the neighbourhood and emergency response services;
• address first aid and medical assistance, firefighting and evacuation of all people at the worksite; and
• provide relevant information and training to all members of the organisation, at all levels, including regular exercises in emergency prevention, preparedness and response procedures.

Emergency prevention, preparedness and response arrangements should be established in cooperation with external emergency services and other bodies where applicable

Question 2

What does the ILO convention 155 require for chemicals and emergencies?

Answer 2

Employers shall be required to ensure that, so far as is reasonably practicable, the chemical, physical and biological substances and agents under their control are without risk to their health.
Employers shall be required to provide, where necessary, for measures to deal with emergencies and accidents, including adequate first aid arrangmeents without risk to health when the appropriate measures of protection are taken.

Question 3

What is the fire triangle?

Answer 3

Three essential elements are required to
produce fire – an ignition source, fuel and oxygen. Fire cannot take place unless these three elements are present in the right proportion; these form a structure called the fire triangle.
The absence of any one of these elements will prevent a fire starting. Prevention depends on avoiding these three elements coming together, and extinguishing depends on removing one of the
elements from an existing fire, and is particularly difficult if an oxidizing substance is present.

Question 4

Define ignition?

Answer 4

Heat acts as the source of ignition, and anything that gives off heat can
start a fire; the source of ignition is not necessarily a flame, a spark or fire
itself, but the heat it gives off.
• Naked flames – from smoking materials, illicit smoking, cooking appliances, heating
appliances and process equipment.
• External sparks – from grinding metals, welding, impact tools and electrical switch gear.
• Internal sparks – from electrical equipment (faulty and normal), machinery and lighting.
• Hot surfaces – from lighting, cooking, heating appliances, process equipment, poorly ventilated equipment, faulty and/or badly lubricated equipment, hot bearing and drive belts.
• Static electricity – causing significant high voltage sparks from the separation of
materials such as unwinding plastic, pouring highly flammable liquids, walking across insulated floors or removing synthetic overalls.

Question 5

Define fuel?

Answer 5

Most substances are combustible under the right circumstances, although those circumstances vary for different materials – principally, in respect of the temperature at which combustion takes place.
The most common sources of fuel are:
• Solids. These include wood, paper, cardboard, wrapping materials, plastics, rubber, foam (e.g. polystyrene tiles and furniture upholstery), textiles
• Liquids. These include paint, varnish, thinners, adhesives, petrol, white spirit,
methylated spirits, paraffin, toluene, acetone and other chemicals.
• Gases. Flammable gases include LPG (liquefied petroleum gas in cylinders, usually butane or propane), acetylene (used for welding) and hydrogen

Question 6

Define the oxygen element in the fire triangle?

Answer 6

The oxygen necessary for combustion is usually supplied from the surrounding air. However, the naturally present oxygen may be enhanced by wind, natural or powered ventilation systems, or by the presence of other sources of oxygen – for example, compressed air.

Note that, as the oxygen in an enclosed space is used up by the fire, the fire will go out, but a sudden entrance of oxygen such as opening a window or door may produce a dangerous occurrence known as ‘backdraught’.

Question 7

List the different classification of fire.

Answer 7

Class A: These are fires involving solid materials, normally of an organic nature,
such as paper, wood, coal, textiles

Class B: These are fires involving flammable liquids or liquefied solids, such as petrol, oil, grease, fats and paint

Class C: These are fires involving gases such as natural gas or liquefied gases, such as butane or propane
.
Class D: These are fires where the fuel is a metal such as aluminium, sodium,
potassium or magnesium.

Class F: These are fires that involve high temperature cooking oils or fats, such as
in the case of chip pan fires.

Electrical fires: Fires involving electrical equipment or circuitry do not constitute a
fire class on their own, as electricity is a source of ignition that will feed a fire until
switched off or isolated.

Question 8

List methods of extinction for fires?

Answer 8

• Cooling. Reducing the ignition temperature by taking
the heat out of the fire, using water to limit or reduce the temperature.
• Smothering. Limiting the oxygen available by smothering and preventing the mixture of oxygen and flammable vapour, by the use of foam or a fire blanket
• Starving. Limiting the fuel supply by removing the source of fuel by switching off
electrical power, isolating the flow of flammable liquids, or removing wood and textiles, etc.
• Chemical interference. By interrupting the chain of combustion and combining the
hydrogen atoms with inert atoms in the hydrocarbons chain.

Question 9

What are the principles of heat transmission and fire spread?

Answer 9

Convection
When air is heated by the fire it becomes less dense and rises through any gap found in the building. The hot air is then replaced by cooler air, creating a current. Convection currents created in the air by fire are a major means of fire spread

Conduction
This refers to the movement of heat through a material known as a conductor, without those materials themselves actually burning. Metals such as copper, steel and aluminium are very effective conductors, whereas concrete and insulation materials are very poor heat
conductors.

Radiation
Often in fire the direct transmission of heat through the emission of invisible heat waves
from a surface can be so intense that adjacent materials are heated sufficiently to ignite.

Direct burning
This is the effect of combustible materials catching fire through direct contact with flames, which causes fire to spread, in the same way as lighting an open fire.

Question 10

What are possible causes of fire?

Answer 10

Careless actions and incidents
This is usually the result of complacency or over familiarity with the work being carried out. It can also be due to poor housekeeping practices, smoking in undesignated areas

Misuse of equipment
This includes items that are not used in accordance with the manufacturers’
instructions, over loading of electrical equipment resulting in sparking, or
not storing chemicals properly.

Defective machinery or equipment
Untested, poorly maintained equipment that is allowed to deteriorate over time, such as worn cables.

Arson
Arson remains a large threat to organisations. Usually this kind of fire is targeted at refuse stores.

Question 11

What are the consequences of fire and how does it injure/kill?

Answer 11

Fires can not only have devastating effects on the workforce but also on the business.
Obviously the business output will be immediately affected. There will be lost production, lost materials, lost products, damage to equipment, etc. But in addition to this the reputation of the company can be seriously depleted and customers who need a service will have no choice but to find other providers.
Fires injure and kill people by:
• suffocation from smoke inhalation;
• poisoning from fumes;
• burning; and/or
• falling and collapsing objects.

Most injuries and fatalities are caused not by the fire itself but from smoke inhalation and collapsing structures.

Question 12

Define a fire risk assessment.

Answer 12

‘An organised and methodical look at your
premises, the activities carried on there, and the likelihood that a fire could start and cause harm to those in and around the premises’.

Question 13

How would you conduct a fire risk assessment?

Answer 13

Step 1: Identify fire hazards.
This will require the identification of ignition, fuel and oxygen sources that may create a fire. This will require looking at the workplace and the activities carried
out.

Step 2: Identify people at risk.
Consider all people in the premises. These can be staff, visitors, contractors and the
public, and the assessment must have special considerations toward vulnerable people such as the old or young, and
disabled.

Step 3: Evaluate, remove or reduce and protect from risk.
Evaluate the risk; this can be quantitative or qualitative. consider two types of risk reduction: prevention and protection

Step 4: Record, plan, inform, instruct and train.
If the employer employs more than five
employees they must record significant findings and develop an emergency plan to ensure the protection of any person at risk

Step 5: Review and monitor.
The fire sources, activities or workplace should be monitored by regular inspections, tours or surveys to check that the appropriate control measures are in fact
in place and people are following the procedures.

Question 14

Outline the 2 types of risk reduction?

Answer 14

Prevention:
• Reduce sources of ignition (maintain equipment, ensure correct use of fuses, work under hot work permit, introduce a smoke policy).
• Minimise potential fuel for a fire (reduce the amount of flammable substances on site, replace materials for a safe form, replace damaged furniture, regularly remove waste).
• Reduce the sources of oxygen (close all doors and windows when not required for
ventilation

Protection:
• Reduce unsatisfactory structural features (remove or treat combustible walls and ceiling lining, improve fire resistance of the workplace, install fire breaks into open voids).
• Improve or introduce fire detection and warning systems.
• Provide adequate means of escape.
• Provision of means to fight a fire.
• Maintenance and testing schedules, including alarm and detection systems, fire doors, lighting and signs.
• Fire procedures and training

Question 15

What needs to be considered for fire risk assessment in temporary work places?

Answer 15

Many fires occur in existing buildings during maintenance and construction work. This type of work and locations present higher fire risks, and extra precautions may be required. A fire risk assessment must be undertaken during the construction stage to ensure that any new
hazards have been identified and that control measures are put in place.

There is a high likelihood that new materials and new ignition sources will have been introduced during the work, and there is also the chance that alarm systems and smoke detectors are isolated or escape routes become cluttered with materials and equipment

Question 16

List the fire control measures.

Answer 16

Correct use and storage of flammable and combustible materials
Control of ignition sources
Reduction and control of oxygen
Systems of work
Good housekeeping

Question 17

What structural measures can be put in place to prevent the spread of fire and smoke?

Answer 17

• Building with fire-resistant structures, especially around escape
routes.
• Installing fire-resistant doors, which can have extra protection
when fitted with smoke seals and intumescent materials.
• Holes and openings in fire-resistant floors, walls or ceilings should be fire stopped by filling them with fire-resistant material to prevent the passage of smoke, heat and flames.
• The use of non-combustible automatic dampers in ducts so that people can leave the workplace before their escape routes become unusable.
• Compartmentalisation to confine the fire to a predetermined size.
• Sprinklers in large compartments.
• Avoid using combustible wall or ceiling linings on escape routes and large areas.

New concepts to prevent fire and smoke spread are:
• quick detection of fires by installing intelligent alarm systems;
• installation of sprinkler systems in all areas; and
• the use of ventilation systems to extract smoke and prevent it from filling the room.

Question 18

What type of electrical equipment is suitable for flammable atmospheres?

Answer 18

• Flameproof enclosure. An enclosure used to house electrical equipment, which when
subjected to an internal explosion will not ignite a surrounding explosive atmosphere.
• Intrinsic safety. A technique whereby electrical energy is limited to such that any
sparks or heat generated by electrical equipment are sufficiently low as to not ignite an explosive atmosphere.
• Increased safety. This equipment is so designed as to eliminate sparks and hot surfaces
capable of igniting an explosive atmosphere.
• Purged and pressurised. Electrical equipment is housed in an enclosure that is initially purged to remove any explosive mixture, then pressurised to prevent ingress of the surrounding atmosphere prior to energisation.
• Encapsulation. A method of exclusion of the explosive atmosphere by fully
encapsulating the electrical components in an approved material.
• Oil immersion. The electrical components are immersed in oil, thus excluding the
explosive atmosphere from any sparks or hot surfaces.
• Powder filling. Equipment is surrounded with a fine powder, such as quartz, which does not allow the surrounding atmosphere to come into contact with any sparks or hot
surfaces.
• Non-sparking. Sparking contacts are sealed against ingress of the surrounding
atmosphere; hot surfaces are eliminated.

Question 19

How may fire be detected?

Answer 19

1. By sensing the presence of smoke or other fumes (often invisible) given off by
   combustion.
2. By detecting the presence of flames and, therefore, a degree of illumination.
3. By sensing heat – an actual temperature or the rate of a rise in temperature.

Question 20

Outline 3 types of detectors in fire safety.

Answer 20

Smoke detectors
There are two types of automatic smoke / fumes detector:
• Ionisation devices: these are sensitive in the early stages of a fire when smoke particles are small, and their sensitivity tends to drop as particles grow in size; however, the detector may mistake dust for smoke, resulting in a false alarm.
• Optical devices: these are effective in situations where there is dense smoke (i.e. large particles) which obscures or changes the normal levels of light in the protected area.

Radiation detectors
The flame of a fire emits not only visible light, but also ultraviolet and infrared radiation. Flame detectors operate on the basis of sensing the presence of these forms of radiation. They are capable of very rapid detection because of the almost instantaneous transmission of radiation to the detector head.

Heat detectors
There are two main types of automatic heat sensors:
• Fusion – where particular alloys melt and either breaks or makes a circuit and sounds an alarm, with the alloys needing replacing after each time that the detector operates.
• Expansion – where a contained metal, air or liquid sensor expands to create a circuit and sound the alarm. These usually reset themselves after having operated and when the conditions have cooled

Flammable gas detection
This measures the amount of flammable gas in the atmosphere and compares the value with a reference value.

Question 21

What conditions need to be considered in choosing fire detectors?

Answer 21

• Conditions in the area to be protected. Dusty or damp atmospheres will affect some detectors more than others. Industrial areas may require different detectors than offices.
• Sensitivity required. The environment must be considered, as highly sensitive detectors will give false alarms in busy environments such as overcrowded offices or kitchens.
• Availability of suitable locations. The detectors should be located so they are in the best possible position to perform their function.
• Potential for false alarms. False alarms can happen for many reasons and are often
unavoidable (for example, dust may be mistaken for smoke by smoke detectors or
strong sunlight can be reflected from windows).

Question 22

What are the 2 types of alarm systems for fire detection?

Answer 22

Manual systems
Not all buildings will have fire alarms installed. Only in smaller, low risk buildings is it acceptable to have hand-operated alarms such as a whistle, rotary gongs, hand bells, triangles or someone shouting, “Fire, fire, get out!”. This system is limited in that the sound won’t be heard across large workplace areas or in between buildings.

Automatic systems
Larger buildings or workplaces with higher fire risks will have call points or break glass
points with sounders, which are used when someone detects a fire. These points are hand operated and are connected to a central alarm, which then sounds the alarm throughout the
building.

Once the alarm has been activated they can be:
• Single stage alarm: The alarm sounds throughout the building and the whole area is evacuated at once.
• Two stage alarm: In large buildings, for example high rises, it would not be practical to evacuate the whole premises at once, as it will create delays. In this case a twostage evacuation may be introduced, where the areas closest to the fire are evacuated immediately and the rest of the areas are placed on standby.
• Staff alarm: This type of alarm is normally used where members of the public are
present, for example in theatres, shops or nightclubs.

Question 23

Name the different types of fire extinguishers and what they can be used for?

Answer 23

Water (red/red)
Works by cooling the burning material to below its ignition temperature, removing the
heat of the fire triangle.
CLASS A FIRES
Solids, wood, paper, cloth, etc

Foam (red/cream)
CLASS A FIRES
Solids, wood, paper, cloth, etc.
CLASS B FIRES
Burning liquids and solids which
melt and turn to liquids as they burn
ELECTRICAL FIRES
Only if they are electrically rated
Smothers the burning liquid and stops oxygen reaching the combustion zone

Dry powder (red/blue)
Smothers the fire, forming a thin layer on the combustible material excluding oxygen
from the burning area.
CLASS A FIRES
Solids, wood, paper, cloth etc. But
only for a short period of time, as
the fire may reignite.
CLASS B FIRES
Burning liquids and solids which
melt and turn to liquids as they burn
CLASS C
Gases, LPG, natural gas; it helps to
isolate the source.
CLASS D
Metals such as magnesium,
aluminium and sodium. Only special
powders are used for thesetype of
fires.
ELECTRICAL FIRES
Only on low voltage

Carbon Dioxide (CO2) (red/black)
Replaces the oxygen in the atmosphere surrounding the fire; only small fires should
be tackled with this type of extinguisher.
CLASS B
Liquids, fats, paints and oil, only
small fires
ELECTRICAL FIRES

Wet chemical (red/yellow)
Has been specially designed to deal with cooking oil fires.
CLASS F FIRES
Cooking oils, deep fat frying pans

Question 24

What are the training requirements for using a fire extinguisher?

Answer 24

• When, and when not, to tackle a fire. If the fire is small and has not involved the building structure, then portable extinguishers can generally be used.
• When to leave a fire that has not been extinguished. As a general rule, once two
extinguishers have been discharged, the fire requires the Fire Service
• General understanding of how extinguishers and other appliances operate.
• The importance of using the correct extinguisher for different classes of fire
• General understanding of how extinguishers and other appliances operate.
• The importance of using the correct extinguisher for different classes of fire

Question 25

What are the main considerations for escape routes?

Answer 25

Suitable means of escape must be provided and maintained. It is essential that people can escape quickly from a workplace and for this reason the means
of escape should be appropriate for the size of the workplace.

Travel distances
The distance travelled by people to a place of total safety – in the open air and away from the building. The measurement of the distance will include travelling around obstacles such as storage systems, desks or equipment. UK guidance suggest the following distances for escape routes:
• For high-risk areas – one minute or 12-25 metres.
• For normal-risk areas – three minutes or 18-45 metres.
• For low-risk areas – five minutes or 45-60 metres.

Stairs
Stairs are a very important part of escape routes, especially in multi-storey buildings where lifts are not used because there is a risk of being trapped and overcome by smoke. Normally they are built with a fire-resistant structure, fitted with fire doors

Passageways or corridors
These should be as straight as possible and lead directly to a place of safety, a fire resistant staircase or open air.

Doors
Doors should open in the direction of travel and the final exit must lead towards the muster point.

Emergency lighting
Escape routes must be well lit, which can be achieved by using external natural or artificial lighting

Exit and directional signs
In the UK, emergency escape signs must be rectangular or square in shape and should contain a white pictogram on
a green background

Assembly points
An assembly or muster point is a place of total safety where staff wait while the incident is investigated

Question 26

What is the main purpose of a fire drill?

Answer 26

• the people who may be in danger act in a calm and orderly manner. Where necessary,those designated carry out their allotted duties to ensure the safety of all concerned;
• the means of escape are used in accordance with a pre-determined and practised plan; and
• if evacuation of the building becomes necessary, it is managed and is carried out in a speedy and orderly manner.