fire protection - riser

7/29/2019 Fire Protection - Riser

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FIRE PROTECTION: RISERPrepared by: Nur Afiqah binti Mohd Bashir

Commonly known asstandpipes system for fireprotection.

It is designed to provide rapidaccess to water in the event

that a fire breaks out.Also bundled with sprinklersystems which providingautomatic or manual sprinklers.


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RISER CONTD

This system also installed in high rise or large

buildings.

Difficult to get pressure, especially on high floors,

which makes it harder to pump water quickly

enough to put the fire out.

There are two types of riser systems which are dry

riser and wet riser systems.


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DRY RISER SYSTEM

A dry riser does not normallycontain water, but is charged with

water by the fire brigade during

an outbreak of fire.

It is suitable for building between20mm-60mm.

Are usually fitted into a staircase

or similarly suitable location.

It must be installed within 18m of

fire engine access to the inlet box

and installed in a fire proof

enclosure.


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DRY RISER SYSTEMCONTD

Comprises a riser pipe withlanding valves at each floor which

canvas hose with nozzles.

Breeching inlets into which the

firemen pump water are provided

at ground level and are connected

to the bottom of the dry risers.

A dry pipe system operates more

slowly and more expensive to

install and maintains than a wet

pipe type.


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Components of Dryriser system

1. Fire Breeching point Should be located on the

external wall of the building at760 mm above ground level and< 12 m from the riser.

The inlets should be within 18 m

of an access road. 100 mm dia. dry riser 2 inlets

150 mm dia. dry riser 4 inlets

2. Dry riser (stand-pipe)

The fire brigade will connect riser

to the water supply The inlets at the ground level and

the pumps force water from themain into riser

Minimum diameter is 100 mm.

2) Dry riser

1) Fire Breechingpoint


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Components of Dryriser system contd

3. Landing Valve Usually install at every

storey.

Space from floor not less

than 750mm Installed with metal box or

cabinet to avoid damage.

4. Automatic air valve

An automatic air valve atthe top of the riser opensto allow air in the pipe toescape, but closes whenthe pipe is full of water.

3) Landing Valve

4) Automatic air valve


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Dry riser inlet box

Horizontal landing valve

Dry Riser Outlet Boxes

Twin Inlet Breeching

Four-way Inlet Breeching


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Operation of Dry Riser System

Water is enteredfrom pillar hydrantby fire bridge when

fire occur

Outlet pump willconnected at Dry

riser inlet

Water will enterfor give the

pressure andremove pressure

air upside

Automatically,water valve located at thetop will open and remove

the air, but will closeagain once the

water has tomeet the dry riser

Firebridge will connec

t them inthe landing valve

and open it

Thensprayed towards

the firewith a pressurizedwater conditions


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Components of Wet risersystem

1. Fire brigade breeching point/Hydrant Minimal diameter is 65mm.

Fitted with a coupling compatible withthe local fire brigade. (different hoseconnections)

2. Water Supply & Break Tank Supplied from break tank - >11.5 m,

water main - >27 litre/s

150 mm diameter, 64 mm int. dia.instantaneous male couplings(connection to pump) fire brigade

breeching inlet at street level.

3. Overflow Pipe capable of developing 375 litre/s to

the open air should be connected tothe break tank.

1) Fire brigade breeching

2) Water

Supply &Break Tank

OverflowPipe


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4. Booster Pump seti. Jockey Pump

When the system pressure drop(150psi-230psi) to a preset level,jockey pump starts and charges

the system back to normalpressure

i. Stand-by Pump

Standby pump is startedautomatically when the duty

pump fails. Acts as supportpump.

ii. Duty pump

The duty pump starts when thepressure in the fire sprinkler

system drops below a threshold.

Components of Wet risersystem contd

4) Booster

Pump set


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5. Pipe work & Valves The control valves are used in

combination with the pipe work

to control a direct the flow of

water.6. Riser (stand-pipe)

Have same function with dry

riser system

7. Landing valve

Landing valve from floor level

should not less than 750 mm

Its dia. 64 mm (minimum)

Components of Wet risersystem contd

5) Pipe work

& Valves

6) Riser

(stand-pipe)

7) Landing

valves


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Operation of wet riser system

The drop in waterpressure is detectedby a pressure switch

which in turn startsthe booster pumps

Connectrubberpipe at

hosecoupling

Pump willbe

functioned

whenswitch is on

Openlanding

valve

At the bottom landing

valve,it has orifice platefunctioned as to limitpressure at landing

valve for high building,so it can be limit tomaximum, 520kPa

Water fromthe tank fill inthe riser and

flow torubber pipe.

Excessive water

will flow to drainpipe and it willflow back to thetank, then the

processrepeated

Close thelanding valve

after used.

fire protection - riser

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