Fire Detection & Protection Presentation.ppt

7/28/2019 Fire Detection & Protection Presentation.ppt

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FIRE DETECTION &

PROTECTION SYSTEMS

Engr. ZAFAR AHMEDSuperintending Engineer

PWD E/M P&D CircleDhaka.


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How Does a Fire Work?

Need all threecomponents to start afire

Fire extinguishersremove one or more of

the components


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Fire Tetrahedron

Basic components ofa fire are:

fuel

source of ignition

oxygen

process of

combustionCommonly referred

to as the "firetetrahedron"


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Types of Fires

Class A - fires occur in ordinarymaterials, such as wood, paper, cloth,carpets, and rubbish.

Class B - fires occur in the vapor-air

mixture over the surface of flammableliquids, such as gasoline, oil, grease,paints, and thinners.

Class C - fires occur in or nearenergized electrical equipment

Class D - fires occur in combustiblemetals such as magnesium, titanium,zirconium, lithium, potassium, andsodium.


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Extinguisher Classification

Class A ordinary combustibles (wood,cloth, paper)

Class B flammable liquids, gases,greases

Class C energized electrical equipment

Class D combustible metals

Letter classification given an extinguisher to designate the class or

classes of fire on which it will be effective.

A B CD

Ordinary

Combustibles

Combustible

Metals

Flammable

Liquids

Electrical

Equipment


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Fire/Life SafetyFire Protection

Class A Fires: Ordinary combustiblessuch as wood and paper.

Class B Fires: Flammable and combustibleliquids and gases.

Class C Fires: Energized electricalequipment.

Class D Fires: Combustible metals.Class K Fires: Cooking Oils and Fats.


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COMPARISION OF FIRE CLASSES

AMERICAN EUROPEAN AUSTRALIAN/

ASIAN

FUEL/HEAT

SOURCES

CLASS A CLASS A CLASS A ORDINARYCOMBUSTIBLES

CLASS B CLASS B CLASS B FLAMMABLELIQUIDS

CLASS C CLASS C FLAMMABLELIQUIDS

CLASS C Unclassified CLASS E ELECTRICAL

EQUIPMENTSCLASS D CLASS D CLASS D COMBUSTIBLEMA

TERIALS

CLASS K CLASS F CLASS F COOKING OILOR FAT


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DETECTION AND SUPPRESSION HARDWARE

Fire Alarm Control Panels, Digital / Analogue Addresable Panels

Ionisation Smoke Detectors Duct Mounting Kits

Rate of Heat Rise Detectors Analogue Fire Sensors

Optical Smoke Detectors Callpoints

Combustable Gas Detectors Alarm Bells

Sirens and Strobes Gas Extiguishant Systems

Even the best fire-fighting agent is ineffective without the right detection package. FM-200 fast agent discharge, combined with early fire detection, provides maximum assetprotection and limits the production of combustion and decomposition products.


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Fire Extinguisher


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Different Kinds of Extinguishers

The 4 most common fire extinguishers:

All Purpose Water

Carbon Dioxide

Multi-Purpose Dry Chemical

Dry Powder

Each kind of extinguisher has a specificuse


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Extinguishing Agents

Class ARespond best to water or water type

which lower the fuel below its ignition

point.Class BRespond to Carbon Dioxide, Halogenated

Hydrocarbons (Halons), and dry

chemicals, all of which displace theOxygen supply making combustionimpossible.


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Class C

Respond best to Carbon Dioxide which

displaces the Oxygen.Must have a non-metallic horn to prevent

static electricity and transmission of

electricity to operator from the fire.


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Class C cont.Halons or dry chemicals may be used but

the disadvantage it the powder

contamination which can lead to furtherdamage of electrical components.

Class DResponds best to dry powder which

prevents oxidation and and the resultingflame.


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Fire Extinguishing Agents

Agents work by two methods

Displacing the oxygen

Chemically combining with oxygen to prevent

combustionAgents commonly used

Carbon dioxide (CO2)

Freon (chlorinated hydrocarbon)

Halon 1301 (monobromotrifluoromethane CF3Br)

Nitrogen (N2)


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CO2 is usually limited to to older,

reciprocating engine powered aircraft.

Freon is used in modern aircraft.Halon 1301 is used in modern aircraft.

N2 is typically used primarily in current

systems as a propellant for the other

chemicals.


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Liquid Freon and Halon 1301 are stored under pressure

in liquid form but when released are in gaseous form.

When released the gas can cause frostbite due to

extreme low temperatures during evaporation.

Dry chemical extinguishers are not used because of the

damage caused by toxic and corrosive chemicals.

Some gaseous agents may be considered toxic

because of the rapid displacement of Oxygen when

used.


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Identification of Fire Extinguishers

Class A

Triangle containing the letter A

GreenClass B

Square containing the letter B

Red


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Identification of Fire Extinguishers

Class C

Circle containing the letter C

BlueClass D

Five point star containing the letter

DYellow


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Volume of the room or area

Cause/ Nature of the fire

Contents of area (Flammable objects or materials)

The number of occupants of area

Some agents like Halon 1301 (banned in Montreal Protocol) are toxic

to humans, have adverse effects on the Ozone layer and leave residuesthat are damaging to equipment and machinery. Also, conformity withinternational safety standards like the Montreal Protocol, NFPA 2001and ISO 14520 have to be made, and taken into consideration beforean appropriate agent can be chosen.

Extinguishing Agents are the gases used to put out fires. Specific agents will be required forspecific hazards, and in order for it to be completely effective extinguishing agent must-cause minimal or no damage to any equipment within the hazard area

not have any ill effects on personnelput out the fire in a minimal amount of time (10 seconds)The extinguishing agent depending on the following variables:

EXTINGUISHING AGENTS


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All Purpose Water

Use on CLASS A

fires

Pressurized water

Pressure gauge


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Carbon Dioxide(CO2)

Use on CLASS Band

CLASS C fires

Hard, plastic nozzle


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Dry Chemical ExtinguishingSystems

Use the same types of finelypowdered agents as dry chemicalfire extinguishers

Agent kept in self-pressurized tanksor in tanks with an external

cartridge of carbon dioxide ornitrogen that provides pressurewhen the system is activated.


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Multi-Purpose Dry Chemical

Use on CLASS A,CLASS B, andCLASS C fires

Fine powder underpressure

Pressure gauge


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Maintaining Portable Fire Extinguishers

Must maintain in a fully charged andoperable condition

Must keep in their designated placesat all times except during use

Must conduct an annual maintenancecheck

Must record the annual maintenance

date and retain this record for oneyear after the last entry or the life ofthe shell, whichever is less


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PortableFire Extinguishers

Extinguishers shall be distributed so that

maximum travel distances apply:

Class A 75 feet

Class B 50 feet

Class C Based on appropriate patternClass D 75 feet


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Emergency Procedures

Building Evacuation

Proceed to nearest exit in an orderly fashion

Assemble at least 100 feet from building

Provide emergency crews with informationabout people still in the building

Provide information to emergency crews about

the reason for evacuation Neverre-enter a building until instructed to by

the police department, fire department.


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Carbon Dioxide (CO2) Extinguishing Systems

Designed toprotect a single

room or a series ofrooms

Should beconnected to the

buildings firealarm system


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Several fire extinguishing cylinders work as extinguisher tank under pressure


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FM 200 CYLINDERS

DETECTORS/SENSORS

FIRE CONTROLPANEL

DISCHARGE NOZZLES

BASIC FM 200 INSTALLATION

ELECTRICAL PIPEWORK

FM 200 GAS PIPEWORK

LEGEND


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A TYPICAL FIRE DETECTION SYSTEM


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Introduction

Fire protection systems have fairlystandardized design requirementsacross North America.

Most areas follow the applicable NFPAstandards.

Local fire prevention and building codes

may require different types of systemsfor different buildings. In BangladeshBNBC is followed.


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Fire Alarm and DetectionSystems (1 of 2)

A fire detection system recognizeswhen a fire is occurring and

activates the fire alarm system.

Alerts occupants

May alert the fire department

May automatically activate firesuppression systems


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Fire Alarm and DetectionSystems (2 of 2)

Fire alarm and detection systemscan be very simple or very complex.

These systems generally have the samebasic components.


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Fire alarm system control panel

A simple control Panel

An integrated control panel

Control Panel

With auto dialer

Control Panel

With Suppression

System
http://en.wikipedia.org/wiki/File:Potomac_hall_facp.jpghttp://en.wikipedia.org/wiki/File:Fire_alarm_diag2.jpg


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Conventional panels have been around ever since

electronics became small enough to make them viable.

They are no longer used frequently in large buildings, but

are still used on smaller sites such as small schools, stores,

restaurants, and apartments.

A conventional system employs one or more initiating

circuits, connected to sensors (initiating devices) wired in

parallel. These sensors are devised to decrease the circuits

resistance when the environmental influence on any sensor

exceeds a predetermined threshold. In a conventional

system the information density is limited to the number ofsuch circuits used. A small map of the building is often

placed near the main entrance with the defined zones

drawn up, and LEDs indicating whether a particular

circuit/zone has been activated. Another common method is

to have the different zones listed in a column, with an LED

to the left of each zone name, or to use an LCD interface to

display information.

The main drawback with conventional panels is that one

cannot tell which device has been activated within a circuit.

The fire may be in one small room, but as far as emergency

responders can tell, a fire could exist anywhere within a

zone

Control Panel type: Conventional


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Multiplex systems, a sort of transition between

conventional and modern addressable systems, were

often used in large buildings and complexes from themid to late 1970s into the late 1980s. Early on, these

systems were programmed to function as large

conventional systems. Gradually, later installations

began to feature components and features of modern

addressable systems. These systems were often

capable of controlling more than a building's firealarm system (i.e. HVAC, security, electronic door

locks...) without any type of alarm or trouble condition

present. While the main panel was the brains of the

system and could be used to access certain

functions, fire alarm controls were usually accessed

through transponders. These were smallerconventional panels programmed to 'communicate'

the status of part of the system to the main panel and

also could be used to access basic fire alarm control

functions

Control Panel type: Multiplex


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ALARM SYSTEMS

Alarm systems can be divided into four groups: local,auxiliary, central station, and proprietary.

All types of alarm systems should be equipped with a

signal system that clearly communicates to all persons inthe building, plant, or laboratory.

Whenever an alarm is sounded in any portion of thebuilding or area, all employees must know what the sound

means.


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Central Station Systems

Central station systems are available in most major citiesaround the country.

Operated by trained personnel, a central station continuallymonitors a number of establishments and, in case of an alarm,calls a nearby fire station and alerts the buildings personnel.

Central station devices are almost always leased.

Proprietary Alarm Systems

Proprietary alarm systems feed alarms to the buildingsmaintenance force, and, optionally, to the fire department as

well.

One reason for their acceptance is that insurance regulations

generally require security officers.

R id ti l Fi Al S t


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Residential Fire Alarm Systems(1 of 2)

Single-station smokealarm most commontype of residential fire

alarm system. Includes both a

smoke detectiondevice and an audiblealarm within a single

unit Millions installed in

private dwellings andapartments


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Fire Alarm System Components

Three basic components in a firealarm system:

Alarm initiation device

Alarm notification device

Control panel


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May performadditionalfunctions, and may

interface with othersystems andfacilities

Vary greatly

depending on ageof system andmanufacturer

Fire Alarm System Control Panels(2 of 3)


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Used to silence the alarm and reset thesystem

Many buildings have an additional display

panel, called a remote annunciator in aseparate location.

In some systems, a battery in the firealarm control panel will automatically

activate when the external power isinterrupted.

Fire Alarm System Control Panels(3 of 3)

36


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Manual Initiation Devices

Designed so thatbuilding occupants canactivate the fire alarmsystem

Primary manualinitiation device is themanual fire alarm box,or manual pull-station.

Once activated, should

stay in the activatedposition until it isreset.

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Double-Action Pull Stations

Variation on thedouble-action pull-station, designed toprevent malicious false

alarms, is covered witha piece of clear plastic

Often used in areaswhere malicious falsealarms frequentlyoccur


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Smoke Detectors

Designed to sense thepresence of smoke

Commonly found inschool, hospital,

business, andcommercialoccupancies with firealarm systems

Most common are

ionization andphotoelectricdetectors.


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Fixed Temperature Heat Detectors

Designed tooperate at a presettemperature

Usually use a metalalloy that will meltat the presettemperature


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Gas Detectors

Calibrated to detect the presence of aspecific gas

Need regular calibration

Usually found only in specificcommercial or industrial applications


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Air Sampling Detectors

Continuouslycapture airsamples and

measure theconcentrations ofspecific gases orproducts of

combustion

I id fi ti f S k d t t


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1: Optical chamber

2: Cover

3: Case moulding4: Photodiode (detector)

5: Infrared LED

Inside configuration of Smoke detector

Photoelectric smoke detector

Ionization smoke detector

Alarm initiating device types


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CO2 Gas detector Smoke detector

Heat detector

Rate of riseInfrared Flame detector

Alarm initiating device types

Manual Call point

Or Hand Operated

Initiating Device

Heat detector

Fixed temperature

Ionization versus Photoelectric


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Ionization versus PhotoelectricSmoke Detectors (1 of 2)

Ionization detectors are triggered bythe invisible products of combustion.

Photoelectric detectors are triggeredby the visible products ofcombustion.

I i ti Ph t l t i36


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Ionization versus PhotoelectricSmoke Detectors (2 of 2)

36


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Thermo-switch System

A circuit in which one or more thermal

switches are connected to an electrical

circuit with a warning horn and an aural

alarm to alert the flight crew that an over-heat condition is present.

If more than one thermal switch is used

they are connected in parallel, so closing of

any one switch will provide warning.


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Thermocouple System

Also called a rate of rise detection system.

A circuit where one or more thermocouples

are connected in series to activate an alarm

when there is a sufficient temperatureincrease at the sensor.

Thermocouples are made of two dissimilar

metals which are twisted together inside anopen frame.


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Thermocouple System

The frame allows air to flow over the

wires without exposing the wires to

damage.The exposed wires make a hot

junction.

The cold junction is located under theinsulating material in the sensor unit.


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False Unwanted and


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False, Unwanted, andNuisance Alarms

Malicious False Alarms

Caused by individuals who deliberately activate

a fire alarm when there is no fire Unwanted Alarms

Occur when an alarm system is activated by acondition that is not really an emergency

Nuisance Alarms Caused by improper functioning of an alarm

system or one of its components


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Fire Department Notification

Fire alarm systems can be brokendown into five categories, based onhow the fire department is notified of

an alarm: Local alarm system

Remote station system

Auxiliary system

Proprietary system Central station


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Fire Department Notification

Local Alarm System

Does not notify the fire department

The alarm sounds only in the building to

notify the occupants.

Remote Station System

Sends signal directly to fire department

or to another monitoring location via atelephone line or a radio signal


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Fire Suppression Systems

Include automatic sprinkler systems,standpipe systems, and specializedextinguishing systems such as dry

chemical systems

Understanding how these systemswork is important because they can

affect fire behavior


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Automatic Sprinkler Systems

In most automatic sprinkler systems,the sprinkler heads open one at atime as they are heated to their

operating temperature. One of the major advantages of a

sprinkler system is that it can

function as both a fire detectionsystem and a fire suppressionsystem.

Automatic Sprinkler System 36


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Automatic Sprinkler SystemComponents

Four majorcomponents: Automatic

sprinkler heads

Piping

Control valves

A water supply,

which may or maynot include a firepump


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Automatic Sprinkler Heads

The working ends of asprinkler system

Composed of:

A body, which

includes the orifice(opening)

A release mechanismthat holds a cap inplace over the orifice

A deflector thatdirects the water in aspray pattern


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Fusible Link Sprinkler Heads

Use a metal alloy,such as solder thatmelts at a specifictemperature

Alloy links two otherpieces of metal thatkeep the cap in place.

When designatedoperating

temperature isreached, solder meltsand the link breaks,releasing the cap.


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Frangible Bulb Sprinkler Heads

Use a glass bulbfilled with glycerinor alcohol to hold

the cap in place As bulb is heated,

liquid absorbs theair bubble andexpands until it

breaks the glass,releasing the cap.


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Types of Automatic Sprinkler


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Types of Automatic SprinklerSystems

Divided into four categories:

Wet sprinkler systems

Dry sprinkler systems

Preaction sprinkler systems

Deluge sprinkler systems


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Dry Sprinkler Systems (2 of 2)


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Residential Sprinkler Systems

Relatively new, butmany homes nowbeing built include

them Typically use

smaller piping andsprinkler heads

with smallerorifices and lesswater discharge


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Mounting Position


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Sprinkler Piping

Network of pipes thatdelivers water tosprinkler heads

Includes main water

supply lines, risers,feeder lines, andbranch lines

Usually made of steel

Plastic pipe sometimes

used in residentialsystems


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Water Supplies

Water may come from municipalwater system, on-site storage tanks,or static water sources.

Water supply must be able to handledemand of the sprinkler system, aswell as the needs of the firedepartment.

Preferred water source for a sprinklersystem is a municipal water supply.


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Fire Pumps

Used when thewater comes froma static source

May also be usedto boost thepressure in somesprinkler systems,

particularly for tallbuildings


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Class I Standpipes

Designed for useby fire departmentpersonnel only

Each outlet has a2 1/2" malecoupling and avalve to open the

water supply afterthe hose isconnected.


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Class II Standpipes

Outlets generallyequipped with a lengthof 1 1/2" single-jackethose preconnected tothe system.

Intended to enableoccupants to attack afire before the firedepartment arrives,but safety and

effectiveness isquestionable.


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I d F i ti L


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Increased Friction Loss

Sediment and Debris Incrustation from Mineral Deposits


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Whats A Fire Door?

Fire doors are designed towithstand fire, heat and smokefor a period of 20-minutes to 3hours.

Did you know that corridoroffice doors are fire doors and

should have a 20 minuterating?

Corridor laboratory doorsshould have a 60 minute rating.

Fire Doors are required to:

Be Self Closing: fire doorsshould have a door closurethat pulls doors completelyshut after the door hasbeen opened

Have Positive latching: apositive latch locks a doorin place so can open swingopen freely.


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Electrical hazards are the cause of numerousworkplace fires each year. Faulty electrical equipmentor misuse of equipment produces heat and sparks thatserve as ignition sources in the presence of flammableand combustible materials.

Examples of common ignition hazards:

Overloading circuits

Use of unapproved electrical devices

Damaged or worn wiring

Fire Safety-Electrical Issues


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Electrical Fire Safety

Avoid the followingimproper andhazardous practices:

Never use three prongadapters that allow athree pronged plug toplug into a two prongoutlet.

Never use any itemwith a damaged orfrayed electrical cord.

Space Heaters are notallowed in campusbuildings.

Never daisy chain orpiggy back multi-plugstrips and electricalcords (plugging strips

and cords into eachother).

Piggy-backed

multi-plug

strips


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Electrical Fire Safety

Avoid the followingimproper andhazardous practices:

Never use three prongadapters that allow athree pronged plug toplug into a two prongoutlet.

Never use any itemwith a damaged orfrayed electrical cord.

Space Heaters are notallowed in campusbuildings.

Never daisy chain orpiggy back multi-plugstrips and electricalcords (plugging strips

and cords into eachother).

Piggy-backed

multi-plug

strips


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QUESTION & ANSWER


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THANK U

&

See Again

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