Dry Powder

Report
NEBOSH Fire
Certificate
Element 4 Part 2
Issue Oct 2011
Fire Protection in Buildings
FIRE EXTINGUISHER LOCATION,
IDENTIFICATION AND USE
Fire Extinguisher
FIRE EXTINGUISHERS ARE
PROVIDED TO REMOVE
PARTS OF THE TRIANGLE
OF FIRE THEREBY
PREVENTING COMBUSTION
FROM CONTINUING.
OXYGEN
SMOTHERING
CLASSIFICATION OF FIRES
• There is not a universal fire-extinguishing agent and
therefore there is a possibility that using particular types
of fire extinguishers on ignited materials or liquids may
make the fire considerably worse and place the fire
fighter at risk.
• Under British Standard EN-2 (Classification of Fires),
fires have been divided into broad classifications for
extinguishing purposes. This will assist in selecting the
most effective fire-extinguishing agent to be used, on the
most appropriate type of fire and burning material
SIGN, COLOUR &
PICTOGRAM
CLASSIFICATION OF FIRES
Wood / Furnishings Etc
CLASS A:
All solid materials, usually organic origin nature (contains
compounds of carbon) and generally produce glowing embers - i.e.
wood, textiles, curtains furniture and plastics
Flammable Liquids &
Solids
Class B:
All flammable liquids and solids, which can also be sub-divided into:
Non-miscible with water (i.e. petrol, oils, solvents, paints & waxes)
Polar Liquid Fires (Hydrophilic/Miscible) with water (e.g. alcohol,
methanol, acetone, propanol, & ethanol etc) - sometimes known as
Polar Liquids.
Note: Hydrophilic = having an affinity with water / Miscible =
'capable of being mixed'
Fires involving Gases
CLASS C:
Class ‘C’ fires involve Natural Mains Gas, Liquid Petroleum Gases
(e.g. LPG - Butane & Propane etc) and Medical or Industrial gases.
SIGN, COLOUR & PICTOGRAM
CLASSIFICATION OF FIRES
Fires Involving Metals
CLASS D:
Class ‘D’ fires involving metals or powdered metals etc (where water is generally
ineffective and / or dangerous).
Specialist Dry Powders are produced for certain Class ‘D’ fires (i.e. M28), particularly
those involving alkali metals such as Sodium & Potassium. These Dry Powders
extinguish metal fires by fusing the powder to form a crust, which excludes oxygen from
the surface of the molten metal. A specific agent is added to prevent the powder from
sinking into the surface of the molten metals
Electrical
Electrical fires are not considered to constitute a fire class on their own, as electricity is
a source of ignition that will feed the fire until removed. When the electrical supply has
been isolated, the fire can be treated (generally) as ‘Class A’ for extinguishing purposes.
However, you should always isolate the supply before fighting the fire; if this is not
possible then a non-electrical conducting extinguishing agent is to be used regardless of
the power status, on all occasions.
Warning Note! - Some electrical equipment can store in capacitors, lethal voltages even
if their power supply has been isolated. Always use extinguishers containing a nonelectrical conducting extinguishing agent specifically designed for use on electrical
equipment such as Carbon Dioxide (CO2) or Dry Powder.
High Temperature
Cooking Oils
CLASS F:
New class specifically dealing with high temperature ( 360°C) cooking oils used in
large industrial catering kitchens, restaurants and takeaway establishments’ etc.
Cooking oil fires, because of their high auto-ignition temperatures, are difficult to
extinguish.
Conventional extinguishers are not effective for cooking oil fires, as they do not cool
sufficiently or may even cause flash back, thereby putting the operator at risk. These
extinguishers contain a specially formulated wet chemical which, when applied to the
burning liquid, cools and emulsifies the oil, extinguishing the flame, sealing the surface
Fire Extinguisher Colour Scheme
European legislation dictates that all extinguishers have
to have a Red body with an identifying label or band on it.
The following colour codes apply:
WATER
FOAM
CO2
DRY POWDER
Red body with WHITE label
Red body with CREAM label
Red body with BLACK label
Red body with BLUE label
9 LTR WATER
Red body with white labelling
Used on CLASS A fires
involving solid materials such
as paper, wood, solid plastics
Extinguishing method:
COOLING & SMOTHERING
Do NOT use on Oil based
fires, electrical fires or fires
associated with electrical
equipment.
9 LTR FOAM
Red body with a cream coloured
identifying label or band
Used on CLASS B fires involving
flammable liquids or liquefiable solids
such as Petrol, Paint solvents
Extinguishing method:
Smothering
can also be used on class A fires
Dry Powder
Red body with blue labelling
Used on All CLASSES of
fires
(except chip or fat pan fires)
Extinguishing method:
SMOTHERING
Dry Powder
STANDARD DRY POWDER knocks down flames. Best for liquids such
as grease, fats, oil, paint, petrol (except chip or fat pan fires).
MULTI-PURPOSE DRY POWDER knocks down flames and, on burning
solids, melts to form a skin smothering the fire. Provides some cooling effect.
Best for wood, cloth, paper, plastics, coal etc. Fires involving solids. Liquids
such as grease, fats, oils, paint, petrol etc (except chip or fat pan fires).
Danger
This type of extinguisher does not cool the fire very well and care has to
be taken that the fire does not re-ignite. Additionally, although it is safe to
use on live electrical equipment, it does not readily penetrate spaces
inside the equipment and similar care has to be taken to ensure the fire
does not re-ignite
The simplest method of which is usually to isolate the power supply.
Smoldering material in deep seated fire such as upholstery or bedding
can cause the fire to start up again.
CARBON DIOXIDE (CO2)
Red body with a black
coloured identifying
band or label
Provided for use where
fires could be started by
electrical equipment
Extinguishing method:
Smothering
WARNING: Gas from CO2 extinguishers can be harmful if
used in confined spaces as it displaces oxygen in the air.
Ventilate the area as soon as the fire has been extinguished.
HOSEREELS
Red body with white labelling
Used on CLASS A fires
involving solid materials such
as paper, wood, solid plastics
Extinguishing method:
COOLING & SMOTHERING
Do NOT use on Oil based
fires, electrical fires or fires
associated with electrical
equipment.
FIRE BLANKET
Red body case with white
labelling- Blanket in side
Used on fires such as
Chip or fat pan fires, persons on
fire
Extinguishing method:
SMOTHERING
Fire blankets are made of fire resistant materials. They are
particularly useful for smothering fat pan fires or for wrapping
round a person whose clothing is on fire.
FIRE BLANKET
How To Use:
Pull out the blanket from its case
Check the fire is smaller than the blanket.
Hold it well up in front of you by the top
corners and keep your hands tucked in
behind the blanket.
Place it over the fire and smother it.
Turn off power source. i.e. Gas/Electric
Don't take it back off for at least half an hour!
That will let the material cool down.
Portable Fire Fighting Equipment
•
•
•
•
•
•
Duration & Range of Discharge
3KG= 6 seconds
6 KG=9 seconds
10KG= 12 seconds
> 10kg= 15 seconds (all timings approx)
Range will vary check with manufactures data to ensure
that you will not put the operator in danger by being too
close to the seat of the fire
Portable Fire Fighting Equipment
• Siting
• On escape routes
• Near to danger points (not too near that if required
you would increase the danger to the operator)
• Near to room exits (inside or out)
• Multi story buildings same location on each
floor
• If possible in groups to form fire points
• Travel no further than 30m to reach an
extinguisher
• If possible in a wall recess handle about 1m
from floor (wall mounted) or on floor stands
• Away from excesses of heat & cold
Portable Fire Fighting Equipment
Maintenance
• Monthly Inspection- Located in proper place, if discharged,
correct pressure, any obvious damage
• Annual Inspection & Maintenance- Thorough inspection, gas
cartridges & replacement charges should be carried out by a
competent person, may include internal & external inspection
• Test by discharge intervals of 5 years (co2 10 years)
• British Standards recommendations
Portable Fire Fighting Equipment
Training Requirements
• RRFSO 2005 does not specify training for fire
extinguishers it does state “ Suitable & sufficient
instruction & training on the appropriate precautions....to
be taken by employee”
• Further requires training should be carried out
periodically.
• Any person who may be called on to use a fire
extinguisher should be trained in selection & practical
use.
Passive Fire Fighting Systems
• Passive systems are either fully automatic or allow fire
fighting to be done remotely
• Most are water systems but foam or gas may also be
used
• Their action is primarily containment and minimising
damage caused by fire spread
• Extinguishment is secondary
System Types
• Sprinklers
• Water based system fully automatic or semiautomatic
• Deluge/Drenching
• Water or gas based system fully automatic or semiautomatic
• Ventilation/Smoke Control
Sprinklers
• Various types
• Wet pipe, Dry pipe, Alternate
Pre-action.
• Siting and number
depends on fire risk
Typical Components
How Sprinklers Work
• Head fits onto water pipe
• Glass vial or bi-metal closure prevent operation
• Heat causes breakage/release releasing water under
pressure
• Deflector plate ensures spread & coverage
Drenchers
• Provides curtain of water to
protect against radiant heat
• Only vulnerable structures
need cover
• Fire resistance protects
other structures
Drench in Action
Gaseous Systems
• Work by displacing air in workroom
• Combustion cannot continue
• Precautions required to prevent loss of life to occupants
INERGEN Storage
Ventilation/Smoke Control
• Not fire fighting as such
• Ventilation cut off to prevent fire spread
• Smoke removed to allow evacuation in breathable
conditions
Effects of Smoke
Ventilation
Shopping Malls
Smoke Control of Common Escape
Route in Flats
There should be some means of ventilating common
corridors/ lobbies to control smoke and so protect common
stairs
This offers individual protection to that provided by the fire
doors to the stair
•Guidance on the
design of smoke
control systems using
pressure differentials
is available in BS EN
12101-6:2005.
B5 Access and Facilities
• The building shall be designed and
constructed as to provide reasonable
facilities to assist fire fighters in the
protection of life.
• Reasonable provision shall be made within
the site of the building to enable fire
appliances to gain access to the building.
Fire Service Access
•Vehicle access for pump appliance within 45m of “all points”to blocks
of flats
•Or: provide fire mains (not in f/f shaft)
•Fire mains
•New standard BS 9990
•Wet mains required for buildings over 50m
•Dry mains
•Access for pump within 18m
Fire Fighting Shafts/ Fire Mains
Private Fire Hydrants
Smoke Ventilators
Liaison with Fire Authority on Arrival
• Liaison established before emergency situation
• Procedures implemented & staff trained (ensure enough
staff are available to carry out procedures(disabled
evacuation etc)
• Information pack plans of buildings, info on fire alarm
system, water supplies, gas/ electric shut off valve
locations, build construction hazards (asbestos)
• Contents of building COSHH, acetylene
• Out of hours procedures (emergency box location)

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