NEBOSH international general certificate element 10.pptx

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Element 10: Fire
NEBOSH International General Certificate
in Occupational Safety and Health
Unit IG2

Learning Objectives
• Describe the principles of fire initiation, classification and spread.
• Describe the basic principles of fire prevention and the prevention
of fire spread in buildings.
• Describe the appropriate fire alarm system and fire-fighting
arrangements for a simple workplace.
• Describe the factors which should be considered when
implementing a successful fire evacuation of a workplace.

10.1 Fire Initiation, Classification and
Spread

Principles of Fire
Fuel:
A combustible material or
substance consumed during the
combustion process.
Oxygen:
From the air (which is 21% oxygen)
or oxygen-rich substances (oxidising
agents).
Heat or ignition source:
Energy to start the combustion
process.

Principles of Fire
Fire is a rapid chemical process in which oxygen combines
with another substance (‘fuel’) in the presence of a source
of heat.
This reaction is called combustion.
During this reaction, heat, flames and smoke are
produced.

Classification of Fire
This is the EU system.
There is no formal Class E. ‘Electrical fires’ is used for electrical equipment.

Principles of Heat Transmission and Fire Spread
• Direct burning.
• Convection:
‒ Inside.
‒ Outside.
• Conduction.
• Radiation.

Convection
Conduction
Radiation
Principles of Heat Transmission and Fire Spread

Group Exercise
Suggest common causes of fire in the workplace.

Causes
• Electrical equipment.
• Deliberate ignition (arson).
• Hot work.
• Smoking.
• Cooking appliances.
• Heating appliances.
• Unsafe use and storage of flammable liquids and gases.
• Mechanical heat.
• Chemical reactions.

Consequences
• People killed and injured.
• Damage to buildings and contents including
smoke damage.
• Environmental damage, e.g. water run-off.

End of Module 10.1 Exercise
1. What three things are needed for a fire to start?
2. What are the methods of fire spread?
3. Suggest common causes of workplace fire in an office.

10.2 Preventing Fire and Fire Spread

Control Measures to Minimise the Risk of Fire in a
Workplace
Control combustible and flammable materials:
• Solids, liquids, gases.
Control ignition sources:
• Systems of work, smoking, arson.
Use of electrical equipment in flammable
atmospheres:
• Hazardous area classification.
Systems of work:
• Hot processes, machinery, electrical equipment.
Good housekeeping:
• General tidiness, waste control and disposal.

Control of Combustible and Flammable
Materials
• Eliminate use altogether.
• Substitute for lower risk.
• Minimise quantities:
‒ Stock control, housekeeping, waste management.
• Safe use and storage in protected, dedicated buildings.

Control of Combustible and Flammable
Materials
• Should be stored outside.
• Storage area should be fenced with secure, lockable gate.
• Warning signs displayed.
• Ignition sources eliminated.
• Bottles chained upright.
• Separate from other buildings.
• Empty and full bottles separated.
• Oxygen bottles not be stored with LPG.
• Return to store immediately after use.

Control of Ignition Sources
• Electrical equipment.
• Hot work.
• Smoking.
• Cooking and heating appliances.
• Mechanical heat.
• Deliberate ignition.

Use of Electrical Equipment in Flammable
Atmospheres
• Flammable gas/vapour/dust mixed with air can be explosive.
• Electrical equipment can ignite the mixture.
• National legislation controls use of electrical equipment:
‒ In EU, the ATEX Directives.
‒ In UK, transposed as the Dangerous Substances and Explosive
Atmospheres Regulations 2002.

Use of Electrical Equipment in Flammable
Atmospheres
• Zone 0 - a place in which an explosive atmosphere is present
continuously, or for long periods, or frequently.
• Zone 1 - a place in which an explosive atmosphere is likely to
occur in normal operation occasionally.
• Zone 2 - a place in which an explosive atmosphere is not
likely to occur in normal operation but, if it does occur, will
persist for a short period only.
There are corresponding standards for dust explosion hazards -
these are called Zone 20, Zone 21 and Zone 22.

Use of Electrical Equipment for in Flammable Atmospheres
Electrical Equipment Zone
Category 1 Zone 0 or Zone 20

Systems of Work
Permit to work for control of hot work:
• Remove flammable materials from the area.
• Cover items that can’t be removed.
• Sweep the floor.
• Damp down wooden floors.
• Provide suitable fire extinguishers.
• Ensure ‘fire-watcher’ present in the area.
• Check area after work has finished.

Good Housekeeping
• Waste-free.
• Tidy.
• Well-ordered.
• Pedestrian routes clear.

The flash point - the lowest temperature at which a liquid can form
an ignitable mixture in air (the vapour can be ignited by an external
ignition source but combustion is not sustained).
The lower the flash point, the easier it is to ignite the material.
Liquids are classified as:
• Flammable.
• Highly flammable.
• Extremely flammable.
Storage of Flammable Liquids

• Category 3: ‘Flammable liquids’:
‒ Flash point 23oC - 60oC.
‒ Easily ignited with a heat source, e.g. a match.
‒ Maximum storage in work area: <250 litres.
• Category 2: ‘Highly flammable liquids’:
‒ Flash point <23°C.
‒ Boiling point >35°C.
‒ Maximum storage in work area: <50 litres.
• Category 1: ‘Extremely flammable liquids’:
‒ Flash point <23°C.
‒ Boiling point <35°C.
‒ Very easy to ignite at room temperature.

Group Exercise
Consider the storage of flammable liquids, e.g. acetone,
petrol, etc.
Discuss safe storage arrangements if such substances
were used at work.

• Use the minimum volume of liquid required.
• Liquid should be in a properly labelled container.
• Ideally, the container will be metal with a self-closing lid.
• Use a metal tray to catch spills and have absorbent material
available.
• Use away from heat and ignition sources.
• Ensure that workspace is well-ventilated.
• Return containers to safe storage after use.

Small quantities:
• Use minimal quantities.
• Store sealed (lids on, or self-closing lid).
• Flammable cabinet:
‒ Fire resistant (metal).
‒ Lockable lid/doors.
‒ Clearly signed.
‒ Spill tray.
• Away from ignition sources.

Larger quantities:
• Purpose-built, single-storey flammables store, segregated chemicals.
• Built of non-combustible materials, lightweight roof for explosion relief.
• Built outdoors away from other buildings or having firewall protection.
• The store suitably fenced in a secure area.
• All electrical systems intrinsically safe, all other ignition sources eliminated.
• Store being well-ventilated at high and low levels.
• All access doors lockable with sill to contain spillages.
• Adequate fire-fighting equipment, suitable fire safety signs.
• Regular checks for security, safe storage of substances.
• Clear, safe access for fire service, adequate means of escape.

Compartmentation
• Keeping fire and smoke in or out of area of building.
• Creating enclosed/sealed boxes using fire-resistant materials.
• Fire is contained in one part of the building.
• Only fully effective if openings in the compartment walls are
sealed.
• Local building regulations play a major part in applying high
standards of compartmentation to workplaces.

Characteristics of fire door:
• Able to withstand fire for a set time (e.g. 30 mins).
• Fitted with self-closing devices.
• Fitted with intumescent strip (expands when hot).
• Fitted with a cold smoke seal.
• Have vision panels of fire-resistant glass (typical).
• Clearly labelled.
Compartmentation

Properties of Common Building Materials
Surface treatment can improve fire performance:
• Encasing steel in concrete.
• Intumescent paint.
• Insulation.
• Wall coverings.
Concrete: Usually performs well in a fire.
Steel: Severely affected by high temperatures.
Brick: Usually very resistant.
Timber: Thin timber will burn quite quickly; thick timber will
survive for longer.

Properties of Common Building Materials
Insulation:
• Must be fire retardant.
Wall coverings:
• Can be flammable so need to be carefully selected.

Protection of Openings and Voids
Openings:
• e.g. service conduits, air handling ducts.
Voids:
• e.g. stairwells, voids between floors, roof voids.
Protection:
• Self-closing shutters.
• Fire break walls.
• Procedure to seal any new openings, e.g. with fire-
retardant foam.

10.3 Fire Alarm Systems and Fire-Fighting

Fire Detection and Alarm Systems
• Simplest system:
‒ Someone shouts ‘Fire!’
• Simple with more noise:
‒ Hand bell, whistle or air horn.
• Manually operated fire alarm:
‒ Manual call points.
• Interlinked smoke alarm:
‒ Links normally unoccupied rooms to interlinked smoke alarms.
• Automatic fire detection and alarm:
‒ Automatic detectors, manual call points, linked to sounders/lights.
The sophistication will depend on the complexity of workplace.

Fire Detection and Alarm Systems
Smoke detectors:
• Detect small smoke particles.
• Very sensitive, early warning.
• Two main types: ionising and optical.
• Can give rise to false alarms.
Heat detectors:
• Detect excess heat generated by a fire.
• Less sensitive, later warning.
• Two main types: rate of rise and fixed temperature.
• May not detect fires that are giving off smoke but not much heat.

Portable Fire-Fighting Equipment
• Fire extinguisher.
• Fire blankets:
‒ Physically smother fires, e.g. fat fires in kitchens.
• Hose reels:
‒ Used in large buildings for fire teams.
• Sprinkler systems:
‒ Sited in buildings and warehouses.
‒ Automatically dowses the fire.

Extinguishing Media

Siting, Maintenance and Training
• On fire exit routes.
• Close to exit doors.
• Close to specific hazards.
• Fixed to the wall or on stand/trolley.
• Clearly visible.
• Signed.
• Unobstructed access.

Inspection:
• Regular and frequent to ensure they are:
‒ In place (firing pin).
‒ In good working order.
Maintenance:
• Ensure they remain in safe working order.
• Once a year.
• Certificated engineer.
• Inspection, testing, dismantling.

• Theory training.
• Types of extinguisher.
• Hands-on experience.
• Records kept in line with local regulations.

Access for Fire and Rescue Services
The requirements for vehicle access differ depending on the:
• Presence of fire mains.
• Size of the building.
• Type of fire appliance to be used.
• For small buildings without a fire main, access for a pump appliance should be
provided to 15% of the perimeter.
• For large, high-rise buildings, the entire perimeter will need to be accessible.
• Site should have an emergency plan including liaison with fire service.
• Familiarisation visits may be carried out.

1. What are the different ways of detecting fire and
sounding the alarm?
2. Name the different types of fire extinguisher and
the class of fire they can be used on.

10.4 Fire Evacuation

Means of Escape
• Available to every person in the workplace.
• Does not require use of lifts (expect in special cases).
• Must take person to a place of safety.
• Two or more separate routes may be required.
• Travel distance should be short.
• Adequate width.
• Clearly signed.
• Appropriately lit.
• Emergency lighting.
• No obstructions.

Travel Distances
Depends on:
• Number of people occupying a room.
• Travel distance to nearest available:
‒ Final exit - to a place of total safety.
‒ Storey exit - into protected stairway.
‒ Separate fire compartment - containing final exit.
• Fire risk.
• Number of alternative escape routes available.

Stairs and Passageways
• Fire-resistant protection.
• Adequate width:
‒ Consider wheelchair users.
• Unobstructed.
• No storage of materials or equipment.

Doors
• Easy to operate.
• Adequate width.
• Open in direction of travel.
• Not locked.

Emergency (Escape) Lighting
• At night or where there is no natural light.
• To indicate escape routes.
• To indicate call points and fire-fighting equipment.
• Regular maintenance.
• Routine inspection/testing.

Exit and Directional Signs
• Standard shape.
• Standard colour.
• Pictogram.
• Easy to interpret.
• Clearly visible.

Assembly Points
• Safe distance from building.
• Safe location.
• Further escape possible if
needed.
• Must not impede fire-fighters.
• Clearly signed.
• 'Refuges' for disabled workers.

Group Exercise
Under your tutor’s direction, take a tour of an area of the building
you are in.
Note:
• Fire compartment, e.g. stairwells, fire doors, etc.
• Travel distances.
• Fire detection and alarms.
• Fire extinguishers, etc.
• Emergency lighting, signage.

Emergency Evacuation Procedures
Emphasis is on personal safety:
• Sound the alarm.
• Get out of the building.
• Stay out of the building.
More complex procedures needed for
some workplaces, e.g. hospitals.

Fire Marshals
Typical duties:
• Check all areas are evacuated.
• Assist disabled/infirm workers.
• Ensure fire escape routes are kept clear.
• Ensure windows and doors are closed.
• Conduct roll call at assembly point.

• Ensure all persons accounted for.
• May not be practical, e.g. supermarkets.
Roll Call

Provision for the Infirm and Disabled
• Staff with disabilities may need personal evacuation plans:
‒ Assist with travel downstairs.
‒ Alert those with hearing impairment.
• May need to consider temporary disabilities, e.g. use of crutches.
• Consider also evacuation of young/elderly.

Building Plans and Emergency Escapes
Fire plans should include:
• Who is likely to be in premises.
• Action to be taken on discovering fire.
• Escape routes.
• Fire-fighting equipment.
• Action to be taken after evacuation.
• Training.

Training and Information
Information on fire safety procedures for:
• Employees.
• Contractors.
• Visitors and the public.
Training for staff:
• Who use portable extinguishers.
• Fire marshals.
• Assist disabled or infirm people.
• Members of the fire team.

Fire Drills
• Usually once or twice a year.
• Allows staff to practise procedures.
• Allows for testing of those procedures.
• Records kept.

1. What general principles should be applied when
establishing means of escape?
2. What is the purpose of emergency lighting?
3. What might fire marshals do in the event of an
evacuation?

Summary
In this element, we have:
• Outlined some of the basic principles of fire safety such as: the fire
triangle, the five classes of fire, the methods by which fire can
spread and some of the common causes of workplace fires.
• Explained how fire and the spread of fire can be prevented by
controlling potential fuel sources and potential ignition sources.
• Outlined the structural measures that exist to contain fire and
smoke in the event of a fire starting, and the use of self-closing fire
doors.

• Described the general principles of fire detection and alarm
systems.
• Discussed types of fire extinguisher commonly used, such as
water, carbon dioxide, foam, dry powder and wet chemical, and
the strengths and limitations of each type.
• Outlined the principal characteristics of a means of escape.
• Described basic requirements for evacuation procedures, fire
marshals, training and information, the capabilities of
employees, fire drills and special procedures for the infirm or
disabled, and the inclusion of escape routes in building plans.
Summary

NEBOSH international general certificate element 10.pptx

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