FIRE SAFETY

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FIRE SAFETY

• NEBOSH Certificate

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FIRE SAFETY - Aims to minimise consequences of
fires

• PREVENTION
• make sure fires dont start
• PRECAUTIONS
• minimise the damage from fire
• PROCEDURES
• action to take in the event of fire

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HAZARDS OF FIRE

• flames and heat
• toxic/combustible smoke and gases
• structural failure of buildings
• oxygen depletion

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FIRE TRIANGLE - principles of combustion
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Sources of fuel
FLAMMABLE SOLID
FLAMMABLE LIQUID
FLAMMABLE GAS
OXIDISING AGENT
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SOURCES OF IGNITION - examples

• Radiant or convected heat from heaters
• friction
• hot surfaces
• chemical
• sparks
• smoking

• electricity static or mains
• internal combustion engines
• tools
• Flame

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Principles of heat transmission and fire spread
convection
radiation
conduction
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Spread of fire

• Conduction - spread of heat energy through
  solids
• Convection - heat transfer through a fluid or
  gas, involving expansion and movement
• Radiation - emission of heat energy through
  electromagnetic radiation in the infra-red part
  of the spectrum, which is then absorbed by matter
  to varying degrees

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Extinction of fires

• Remove one element or more of fire triangle, by
• starving it of fuel
• smothering it to exclude oxygen
• cooling it to reduce temperature.
• Fire-fighting revolves around these principles

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Causes of fires

• Arson
• discarded cigarettes and matches
• faulty plant equipment
• flammable liquids materials storage use
• hot processes
• heating appliances
• combustible wastes
• Arson accounted for 41 of the 43,600 fires
  that occurred in non domestic premises in
  1999 source Home Office

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Art School molotovs
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Elements of fire prevention and control
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Interaction of fire legislation
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The Building Regulations 1991 Approved Document
B Fire safety

• Covers means of escape internal fire spread
  (linings and structure) external fire spread
  access and facilities for the fire service.
• Requirements do not apply retrospectively, but
  will apply to new buildings, or modifications,
  etc to existing buildings

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BS5588 parts 1 11Fire precautions in the
design, construction and use of buildings

• Escape routes horizontal and vertical
• Number of escape routes
• Travel distances within each storey
• Width of exits and escape routes
• Number of persons per floor
• Fire compartmentation
• Fire resistance

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BS5588-111997 Escape distances
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Fire compartmentation in buildings
Fire escape route from various rooms
are protected.
office
laboratory
classroom
Office and classroom similar level of risk no
barrier.
Classroom protected from higher fire risks in
laboratory.
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Means of escape

• A route that can be followed by an occupant,
  unaided or without risk from fire, that will lead
  to safety
• clear marking of route, HSafety (Signs
  Signals) Regs 1996 BS 5499 1990 Fire safety
  signs, notices and graphic symbols, parts 1 3

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Escape 2

• Calculated Time available for escape greater
  than Time needed for escape
• time available calculated on assessment of time
  from fire start and its making escape route
  unsafe
• time taken for everyone to evacuate once the fire
  has been discovered warning given.
• More than one route - 25m(HR), 32m(Norm sleeping
  area), 45m(NR), 60m(LR)
• One route - 12m(HR), 16m(NR sleeping), 18m(NR
  except factories), 25m(incl. Factories), 45m(LR).

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Escape 3

• Protected and unprotected zones
• Escape distances 18m hazardous processes, 45m
  offices
• Fire compartments
• Fire doors - self-closers, smoke seals, etc

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Number width of exits - Escape 4

• There should be enough available exits of
  adequate width, from every room, storey or
  building. Adequacy is assessed on
• doorways min. width 0.75m for upto 40
  people/minute
• doorways min. width 0.8m for wheelchair users
• doorway min. width 1m for upto 80 people/minute
• where more than 80 people/minute need to escape,
  the min. width should be increased by 0.075m for
  every additional 15 people.
• Calculate above on the people in the building
  divided by the time available for escape

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Building fabric - Building Regs 1991, Approved
Document B

• 0.5 or 1 hour fire resistance of doors, walls and
  ceilings materials from which escape routes
  constructed
• Fire resistance of load bearing elements of
  structure
• Compartmentation, to reduce spread of fire,
  complementary to construction of escape routes
• Other - external fire spread, fire service
  access, ventilation

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EVACUATION PROCEDURE - the recommended order of
business

• 1. evacuate the building by the fastest route
• 2. sound the fire alarm
• 3. call the fire brigade
• 4. assemble at the designated location

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FIRE DRILLS

• legal requirement
• effective means of escape
• training exercise
• practice evacuating the building by the fastest
  route and use of assembly points
• test emergency procedures
• role of fire marshals to aid evacuation and
  prevent re-entry

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Fire Precautions Act 1971

• All premises meeting certain criteria must have a
  valid fire certificate
• hotels, boarding houses gt 6 people, or bedrooms
  above/below ground floor
• workplaces, ie. Factories, OSRP premises
• 20 in workplace at one time, or
• 10 above ground floor, or
• explosives or HFs stored or used
• Cert. Issued subject to adequacy of escape
  routes, alarm systems, fire fighting equipment,
  etc

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Fire Precautions (Workplace) Regs 1997 (99)

• Require provision and maintenance of measures to
  detect, fight and warn of fires, ensure safe
  evacuation
• Now, with MHSWR, require FRAs for premises
• Revising FRAs ensures steady improvement, and
  covers buildings not included in FPA 71 and fire
  certificates

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Building management of fire risks

• Good housekeeping by those responsible for
  managing buildings is a combination of
• Following fire risk assessment/Fire Certificate
  recommendations
• Constructing compartments, fire escape routes,
  and installing fire detection and alarm systems
  as necessary
• Reducing potential for fuels and ignition sources
  to mix
• Maintaining readiness to evacuate safely through
  organising staff, instruction and training,
  conducting fire drills and reviewing performance
  of people and systems.

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BS 5839, part12002 - Fire detection and alarm
systems

• Manual - ie. People, who trigger the alarm system
  by activating a break-glass
• Automatic - detectors placed carefully and
  sensitive to heat, smoke or combustion products

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BS5839 part 1 2002 Fire detection and fire
alarm systems for buildings

• Purpose of fire alarm systems protection of
  life and property
• System categories
• M Manual systems
• L 1 5 incorporate automatic fire detection to
  some degree, for the protection of Life
• P 1 2 incorporate automatic fire detection to
  protect Property.

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Fire alarms

• Triggered by automatic smoke or heat detectors or
  person activating a break-glass
• Audible warning, klaxon or bell (can also be
  visual flashing lights for deaf, or vibrating
  pagers for deaf/blind)
• can be shouting fire! or hand-bell in small
  premises
• Detection alarm systems to comply with BS5839
  part 1

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Classification of Fires - BS EN 2

• A - Free burning materials, paper, wood, plastics
  etc.
• B - Flammable liquids, petrol, meths, solvents
  etc.
• C - Flammable gases, methane, hydrogen etc.
• D - Metals, potassium, sodium, magnesium etc.
• Electricity can be involved in any class of fire

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Water extinguishers
Red body Suitable for use on Class A Fires, wood
and paper etc. Not suitable for combustible
liquids, cooking fats etc. Not safe to use on
fires involving electricity Extinguishes by
cooling
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Foam extinguishers
Cream body (Old type) or Red Body with Cream
label. Suitable for Class A and B Fires. Not
suitable for use on fires involving electricity
Extinguishes by cooling and sealing the surface
of a burning liquid.
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Powder extinguishers
Blue body (Old type) or Red body with blue
label. Best on Class B fires but safe to use on
any type of fire. Works by chemically interfering
with the combustion reaction
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Carbon dioxide CO2 extinguishers
Black body (Old type) or red body with black
label (New type). Best on Class B and C fires but
safe to use on any type of fire Safe to use on
fires involving electricity Extinguishes by
reducing oxygen levels and cooling.
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Other fire fighting equipment

• Hose reels
• Fire blankets
• Automatic sprinklers
• Carbon dioxide/Halon systems
• Drenchers

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HFL LPG Regs - definitions

• HFLs - flashpoint (below 32o C) and
  combustibility. Test methods in schedules 1 2
  of Regs.
• LPG - commercial butane, commercial propane, or
  combinations thereof.

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Storage

• Suitable fixed storage tanks in safe positions
  suitable closed vessels in open air and protected
  from direct sunlight or closed vessels in
  storerooms in safe position or fire resisting
  structure or in workroom in fire resisting
  cupboard which is fire resisting structure.

Marking

• Every storeroom, cupboard, bin, tank, and vessel
  used for storing HFLs should be clearly and
  boldly marked Highly Flammable or Flashpoint
  below 32oC
• Where this is impracticable, such a warning is to
  be placed as near to storage as possible.

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Precautions against spills and leaks

• Conveyed through factory in vessels designed to
  prevent spills.
• Process use to be kept as low as r.p.
• Steps taken to prevent storage tanks from
  leaking.
• Spills should be drained off to a safe place.

Sources of ignition

• No ignition sources shall be present where a
  dangerous concentration of vapours from hfls is
  expected to be present.

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Example references

• Fire Precautions Act 1971
• Fire Precautions (Workplace) Regulations 1997 as
  amended
• Building Regulations 1991, Approved Document B
  Fire Safety not retrospective
• BS5588 Fire precautions in the design,
  construction and use of buildings parts 1-11
• BS5839 pt 12002 Fire detection and alarm
  systems for buildings