Fire Protection System_2

7/21/2019 Fire Protection System_2

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FIRE PROTECTION SYSTEM

(Lecture – 2)

Prepared By

Manoj Paudel

1



Fire Detection and Alar

• Fire is detected by observing the temperaturerise, pressure rise or presence of smoke.

• Early detection means, early evacuation and

so less damage life and property!• "#o types of detectors are used for $re

detection%

– &eat 'etectors

– (moke 'etectors

• )s soon as the detectors get activated theyactivate the alarm

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!eat Detector"

• ) #eat detector is a $re alarm devicedesigned to respond #hen the convectedthermal energy of a $re increases the

temperature of a heat sensitive element.• $ed temperature heat detector operate

#hen the surrounding reaches thresholdtemperature

• -ate of rise heat detector operate on rapidrise of temperature degrees per minute!of the surrounding



So$e Detector"

• (moke detectors set the alarm#hen they detect the $re.

• "#o types% Photoelectric (moke'etectors and /oni0ation (moke'etectors.



P#otoelectricSo$eDetector" "here is a light source and a

sensor, but they arepositioned at 234degreeangles to one another

/n the normal case, the light

from the light source on theleft shoots straight acrossand misses the sensor. 5hensmoke enters the chamber,ho#ever, the smoke

particles scatter the lightand some amount of lighthits the sensor.

"he sensor then sets o6 the

horn in the smoke detector. 7



Ioni%ation So$e Detector

/oni0ation smoke detectors use an ioni%ationc#a&er and a source of ioni%in' radiation todetect smoke.

/nside an ioni0ation detector is a small amountperhaps 187333th of a gram! of aericiu2*./t ioni0es the air.

5hen there is no smoke the current 9o#s #hereas

#hen smoke enters the chamber, current is :



Fire Su++re""ion S,"te

;

1-Fire is sensed by Detectors and signal is sent to the Control Unit2-The Control Unit performs a series of actions; shutting down ventilation

systems and equipment, sounding alarms

3-The Agent Containers is propelled through iping and !o""les into the

protected area

4-Discharges as a gas to all areas and quic#ly suppressing the fire



!,drant S,"te

• "he hydrant system is an arrangement of pipes,valves, hose outlets and allied e<uipment.

• "he outlets are located strategically to cover a

large area arc of 1=43m! and thus put out the$re and hence protect both e<uipments andoccupants.

• 5ater is discharged in stream through hose and

no00les attached to such hose outlets.• Pumps are provided to supply #ater to the hose

outlets.

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2

!o"e Reel

In"tallation



'ry &ydrant• For building of height 1= > 3m.

• Pipe initially do not contain #ater, $re

pumps pump #ater #hen re<uired

• (uitable for cold climate

5et &ydrant• Pipe is permanently charged #ith #ater

• ?ot (uitable for cold climate as #atermay free0e in pipe and block 9o#

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Fire &ydrant E<uipments

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1*

/ndoor Fire &ydrant @utdoor Fire &ydrant



Fire (prinkler (ystem

1

) Fire (prinkler (ystem is used as an active$re protection and $re $ghting measures in

commercial and residential industries andmany more, comprising #ith a #ater supplysystem #hich provides an enough pressureand 9o# rate to a #ater supply piping system

onto #hich $re sprinklers are attached.



!o"e Reel and S+rin$ler -aterSu++l,

1

Fu" e n % a so ere



S+rin$ler!ead

Fu" e n % a so erelink in a system of leversholds the #ater outlet shut.)t a predetermined

temperature the soldermelts and #ater 9o# starts.

C#eical% similar to thefusible link but using a

block of chemicaldepending on theapplication.

.la"" &ul&% a <uart0 bulbcontaining a coloured 9uid#ith a high coeAcient ofepansion. lass breaksdue to epansion of 9uid athigh temperature

O+en T,+e % no trigger 17



T,+e" o/ Fire S+rin$lerS,"te

1:

• -et +i+e

– Pipes are permanently charged #ith #ater, Mostcommon type

• Dr,+i+e

– Pipes are $lled #ith compressed air

– #here pipe#ork is eposed to air temperatures belo# 7degree celsius or above ;3 degrees celsius

• Delu'e

– for high ha0ard applications, occupancies #ith rapid

$re spread• PreAction

– #here concerns over #ater damage

– a dry pipe installation but has additional heat detectors

#hich preempt the opening of sprinkler heads andadmit #ater into the pipe#ork



5et Pipe (ystem

• Composed of steel pipes that are al#ays$lled #ith #ater hence, the term D#etD!.

• &as pressuri0ed #ater inside the system

for etinguishing a $re #hen any sprinklerhead gets hot enough to open.

• 5hen the sprinkler head is activated, thepressuri0ed #ater in the pipes is

immediately released, providing a fasterreaction time than any other type ofsystem.

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Ad0anta'e" o/ -et S,"te De"i'n

• S,"te "i+licit, and relia&ilit, 4 5et pipe sprinklersystems have the least number of components .

• Relati0e lo1 in"tallation and aintenancee+en"e 4 'ue to their overall simplicity, #et pipe

sprinklers re<uire the least amount of installation timeand capital. Maintenance cost savings are also reali0ed .

• Ea"e o/ odi3cation 4 5et pipe $re sprinkler systemsare advantageous since modi$cations involve shuttingdo#n the #ater supply, draining pipes and making

alterations.• Fa"ter Reaction Tie

1=



Di"ad0anta'e"

• Free%in' o/ 1ater in +i+e% ?ot suitablefor cold climate regions #here #atercould free0e in pipe

• Floodin' T#reat% due to leakage in

pipes.

(uitable for% Most commercial buildings

?ot suitable for% Buildings #here accidentalleaks could be detrimental, very coldclimate

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'ry Pipe (ystem

• "he pipes are not $lled #ith #ater 4 theyreactually $lled #ith compressed air.

• 5hen the sprinkler head is activated, a

valve releases the compressed air throughthe sprinkler head. @nce all of the air isreleased, the pressure in the pipe changes,allo#ing #ater to $ll the system.

• "hen, this #ater puts out the $re.• 'eluge and Pre4)ction (ystems are

variations of dry system

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• /n Delu'e S,"te" #ater enters the pipes #hentriggered by a heat or smoke detector, separate

from the sprinkler heads. "here may also be amanual function, #here pushing a button orpulling a cord activates the system. "he sprinklerheads in a deluge system are open, meaning they

dont have a trigger function and are activatedsimultaneously.

• Preaction ","te" must be triggered t#ice

before #ater is dispensed from the sprinklerhead. "he $rst trigger 4usually a smoke detectoror a heat detector that is separate from thesprinkler head 4 allo#s #ater into the pipes. @ncethis trigger occurs, the system acts like a #et

pipe system. "he second trigger, the individual *1



'ry (ystem are installed in cold areas#here free0ing of #ater occurs, unheatedbuildings, #arehouses

'eluge (ystems are suitable for chemicalplants or other areas #here the spread of$re #ould be eceptionally ha0ardous.

Pre4)ction (ystems are suitable for placesdealing #ith sensitive property like in amuseum or library.

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4"e o/ Dr,5 Delu'e and PreAction S,"te"



/n Comparison to 5et (ystem 'ry

(ystem has follo#ingdi"ad0anta'e"

• /ncreased compleity

• &igher installation and maintenancecosts

• o#er design 9eibility

• /ncreased $re response time• /ncreased corrosion potential

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Fire Protection System_2

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