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Workplace Safety 3220Workplace Safety 3220
Chapter 3.2
Fire Protection
3.2 Fire Protection3.2 Fire Protection
In this chapter you will understand:
Why fires occur, and
How to properly apply the procedures used to
Prevent,
Detect and
Extinguish fires
3.2 Fire Protection3.2 Fire Protection
Work-related fires have killed hundreds of people in this country and injured thousands of others.
Many fires are caused by the unsafe acts of people through carelessness and a lack of knowledge.
What they all have in common is that they are Preventable.
Fire prevention is Everyone's Responsibility.
The Chemistry of FireThe Chemistry of Fire
For a fire to occur, 4 components are necessary:
Fuel
Oxygen
Heat
Chemical ChainReaction
Common Causes of FireCommon Causes of Fire
Smokers Materials
CigarettesMatchesOpen Flame
Electrical
FusesShort CircuitsOverlaoded CircuitsLoose Connections
Misuse of Flammable Liquids
Fat FiresOily Rags
ExplosionsExplosions
An explosion is
A very rapid, contained fire occurring when the gases produced by the fire exceed the pressure capacity of the container.
A simple example is a firecracker:
1.The fuse burns into the centre of the firecracker.
2.The powder inside ignites and burns very rapidly, producing gas.
3.The paper wrapper cannot withstand the pressure and blows apart.
ExplosionsExplosions
Controlling FiresControlling Fires
Knowing how and why fire burns suggests ways to control it.
Fire can be controlled in the following ways:
By cooling the burning materials
By removing oxygen
By removing fuel
These methods interrupt the chemical chain reaction.
Heat TransferHeat Transfer
Heat always moves from higher temperatures to lower temperatures.
Heat from a fire is transferred to other objects in 3 ways:
Conduction: direct heat transfer through solids and liquids in contact with each other.
Radiation: electromagnetic wave transfer of heat to a solid. Eg. Heat and light from the Sun
Convection: heat transfer through the movement of hot gases.
Types of Heat TransferTypes of Heat Transfer
Spontaneous CombustionSpontaneous Combustion
This can occur when organic compounds decompose and release flammable gas. This leads to a buildup of heat and can result in a fire.
In nature, such as in forests and swamps, gas and heat are vented naturally and fires are rare.
If oily rags are stored in a closed container, heat buildup can cause the oil to vapourize. This creates a potentially dangerous hazard. Propercontainers are required.
Classification of FiresClassification of Fires
Fires are classified according to the types of materials being burned.
Class A FireClass A Fire
Ordinary materials
Wood, paper, garbage
Class A fires are extinguished by the quenching and cooling effects of water.
Class B FireClass B Fire
Flammable or combustible gases and liquids.
Gasoline, kerosene, propane, grease, paint thinner, paint, oil.
Water will spread the fire. Use dry chemicals, CO
2, or
foam.
Class C FiresClass C Fires
Energized electrical equipment.
Appliances, power tools, switches.
Do not use foam or water (they conduct electricity).
Use dry chemicals or CO
2.
Class D FiresClass D Fires
Combustible metals.
Titanium, magnesium, sodium, potassium, phosphorous*.
Do Not use normal extinguishing agents of Class D fires. It can make them more intense. Use only specialized techniques, agents and equipment.
Fire PreventionFire Prevention
Fire PreventionFire Prevention
Practise Good Housekeeping:
Keep work area free of clutterClean flammable dust regularly (sawdust)Wipe up spills of flammable liquidsKeep fire exits and exit routes clearNever use alcohol or gasoline as a cleaning
agentStore flammable waste in proper containersStore flammable liquids properlyExtinguish cigarettes in proper containersObey all “No Smoking” signs
Fire PreventionFire Prevention
Avoid Electrical Hazards
Don't overload circuitsDiscard frayed or worn cordsCheck for problems with electrical equipment
OverheatingFaulty switchesExposed wires
Never use a tool or extension cord if the grounding plug has been removed.
Fire PreventionFire Prevention
Be careful handling flammable, combustible, and explosive materials
Flammable – materials that catch fire and burn easily and give off intense heatLiquids – gasoline,
acetoneSolids –
phosphorous, magnesium, sodium
Gases – propane, acetylene, hydrogen
Fire PreventionFire Prevention
Combustible – materials that will burn under ordinary circumstances because of an outside source
paper, wood, cloth
Fire PreventionFire Prevention
Explosive - materials such as dynamite, nitroglycerin, blasting caps, metal powders, plastic powders, even dust.
Fire PreventionFire Prevention
Keep flammable, combustible, and explosive material away from sources of heat or friction.
Never refuel a hot or running engine
Clean up spills immediately
Look out for empty containers that once held flammable materials
Flammable, combustible, and explosive materials must be properly labelled
Fire PreventionFire Prevention
Minimize the potential for a dust explosion
Can occur when a spark comes in contact with sawdust, mill dust, or other finely divided particles.
Fire PreventionFire Prevention
Be aware of possible ignition sources
FlameCigarettesStatic electricitySparksWeldingFurnacesHot ashHeating elementsElectrical switches
Responding to a FireResponding to a Fire
Know the locations of fire alarms
Know the locations and operation of fire extinguishers
Be aware of the nearest fire exits
Know evacuation procedures
Know where to gather after evacuation
Know the company's procedure for reporting a fire
Escape and Muster PlansEscape and Muster Plans
Industrial FiresIndustrial Fires
Try to eliminate the causes of fires:
Use only approved equipment
Establish Safe Work Practises
Enforce good housekeeping procedures
Train workers to spot hazardous conditions and report them immediately.
Industrial FiresIndustrial Fires
Develop Fire Protection Programs
Design buildings with fire protection in mind
Enforce regular inspections
Train employees in detection, alarms, evacuation, preventing, confining, and extinguishing a fire.
Fire DetectionFire Detection
Fire detection devices include:
Human observers
Automatic sprinklers
Smoke, flame, heat, CO
2, and CO
detectors
Fire DetectionFire Detection
The 2 main tasks of fire detection are:
To give an early warning to allow building occupants to escape
To give an early warning to fire-fighting teams to prevent or minimize losses
Fire DetectionFire Detection
Building should be equipped with fire detection systems that do 2 important things:
Communicate to all where the fire is located
Summon appropriate fire-fighting units.
When an alarm is sounded, all employees must know what the sound means.
A building can have different alarms for different emergencies