Dry riser system

DRY RISER SYSTEM

1.0 DESIGN STANDARDS

• Part 1 Hydrant systems, hose reels and foam inlets.

• Part 2 Landing valves for dry risers.

• Part 3 Inlet breeching for riser inlets.

• Part 4 Boxes for landing valves for dry risers.

1.1 LANDING VALVE

• Provided in each floor and comply with landing valve for dry risers.

• Located at fire access lobbies, protected staircases and protected lobbies.

• Installed not more than 0.75m above floor level.

• To protect landing valves, box are provided.

• Fire hose not less 38mm diameter, 30m length, 60mm diameter and nozzle should be provided.

1.2 BREECHING INLET

• Fire brigade breeching inlet installed at bottom of riser should comply with inlet breeching.

• Breeching inlets enclosed within a box and labeled ‘Dry Riser Inlet’.

• Drain should be provided at bottom of riser to drain the system after use.

• Two-way breeching inlet should provided 100mm diameter dry riser.

• Four-way breeching inlet installed with 150mm diameter dry riser.

• Breeching inlets should located not more than 18m from appliance access road and not more 30m from near external hydrant outlet.

1.3 RISER PIPE

• Riser pipe diameter located within fire access lobby or staircase at 150m if highest outlet more than 22.875m above breeching inlet or otherwise pipe riser diameter is 100mm.

• Riser pipe will galvanised iron to heavy gauzed or class c tested to 21 bar.

• Horizontal runs pipework feeding the risers should slope to enable proper draining.

• Air release valve should installed at top of riser to relief air trapped.

• Riser pipe should electrically earthed or connected to building earth to avoid equipotential.

WET RISER SYSTEM



• Part 1 Landing valves for wet risers.



2.1 WET RISER LANDING VALVE

• Landing valves are provided on each floor and comply with hydrant systems, hose reels and foam inlets.

• Located within fire fighting access lobbies, protected staircases or protected lobbies and installed not more than 0.75m from floor.

• To protect landing valves, boxes are provided and should comply with boxes for landing valves for dry risers.

• Pressure at landing valve should be no lessthan 4 bars and not more 7 bars.

• Two type of landing valves

i) pressure reducing with outlet (required wet riser return pipe)

ii) pressure reducing without outlet

• Fire hose of canvas not less 38mm diameter, 30m length, 6mm diameter quick coupling and jet spray nozzle are provided in hose crdle beside landing valve.

2.2 BREECHING INLET

• Breeching inlet should 4-way type comply with inlet breeching for riser inlets.

• Breeching inlet is enclosed within a box and labelled with ‘ Wet Riser Inlet’.

• A drain are provided at bottom of riser to clean the system.

• Breeching inlets should located not more than 18m from fire appliance access road not more than m from nearest external hydrant.

2.3 WET RISER PIPE

• Located with in smoke free lobby, protected areas within 45m coverage from landing valve.

• More than one riser are required for each floor and distance between risers not more 60m.

• Distance between lowest and topmost landing valve in upper stage riser not more 60m.

• Riser pipe diameter should 150mm galvanised iron to heavy gauge.

• Relief pipe are required with return pipe minimum 100mm diameter, galvanised iron to medium gauge, discharging back to wet riser tank whenever possible.

• Air release valve should installed at top of riser to relief air trapped in system.

• Wet riser pipes should coated with primer and finished with red gloss paint or coded by red bands 100mm width and elbows and tees painted red.

• Wet riser pipes should electrically earthed to achieve equipotential.

2.4 WET RISER PUMPS

• Wet riser pumps draw water from wet riser storage tank and two sets of pump.

• Pump capacity usually sized to deliver a flow rate 1500l/min at running pressure not less 4 bars but not more 7 bars.

• Standby wet riser pumpset should supplied with power from emergency generator it available or it should be diesel engine driven.

• Fuel supply should adequate minimum 2 hours continuous operation.

• Electrical cabling to supply power wet riser pumps should MICC or fire rated type.

• Batteries for diesel engine should maintain free type.

• Wet riser pumpsets should protected from fire and away from locations likely to be flood.

• Some are installed in fire pump room located at basement below external drainage levels.

• It should ventilated by natural or mechanical means and provide with signage.

• Carbon dioxide type portable extinguisher should be provided.

2.5 WET RISER TANKS

• Fire water storage tank should sized for minimum capacity 45 500l with automatic refill rate 455l/min.

• Intermediate break tank for upper stages not less than 11, 375l with automatic make-up flow of 1365l/min.

• Wet riser tank should be pressed steel, FRP or concrete.

• Pressed steel tanks should hot dipped galvanized and coated internally with bituminous for corrosion protection.

• Water tank should be compartmented unless it was reinforced concrete.

• Ball float valves, overflow pipes, drain pipes and water level indicators should be provided at each compartment.

• External surface of tank should painted red or red band minimum 200mm are painted to indicate it is a fire tank.

• Wet riser tank usually are located at ground level, first or second basement.

• Wet and dry tank usually seperated from others tank.

• It may be combine with hose reel tank when tank capacity equal to total water storage for both wet riser for hose reel system.

• Hose reel tap off level should be above riser tap off level to reserve it maintain.

2.6 PUMP STARTER PANELS AND CONTROLS

• Pump starter panel should complete with indicator lights.

• Ventilation slot are provided with insect screen to prevent entry of vermin.

• Cables should be MICC or fire rated type routed.

• It should be located at same room where fire pump are located.

• Wet riser pumps are automatically started upon actuation of pressure switches but stopped manually.

• Three pressure switches are:i) starting duty pumpset at 80%

ii) starting standby pumpset at 60%

Iii )starting and stopping jockey pumpset at 90% and 110%

• Pressure switches normally installed in test drain line on pump discharge side.

• Pressure setting should be clearly labelledon tags attached to each pressure switch.

DOWNCOMER SYSTEM



• Part 1 Landing valves for wet risers.



3.1 DOWNCOMER LANDING VALVE

• Landing valves are provided on each floor and comply with hydrant system, hose reels and foam inlets.

• Located within fire fighting access lobbies, protected staircases or protected lobbies installed not more 0.75m from floor.

• Pressure at landing valve depends on static pressure on valve from roof tank.

• Semi-rigid 40mm diameter hose and nozzles should provided at every landing valve on floor.

• Two sets fire hose of canvas type not less than 38mm diameter, 30m length complete with 65mm diameter quick coupling and jet spray nozzle should provided at caretakers unit or management office.

3.2 BREECHING INLETS

• Fire brigade breeching inlets into firemen pumps water provided at bottom of riser at ground floor.

• It should 4-way type comply with inlet breeching for riser inlets.

• Where it is enclosed within box and label ‘Downcomer Inlet’

• Drain should be provided at bottom of riser to drain system.

• Breeching inlets should located not more 18m from fire appliance access road and not more 30m from nearest external hydrant.

• Check valve installed between topmost landing valve and tank to prevent back flow.

3.3 DOWNCOMER PIPE

• Located within some free lobby or protected areas within 45m coverage from landing valve.

• More than one riser are required for each floor, distance not more 60m.

• Riser pipe diameter should 150mm galvanised iron to heavy gauge.

• Released valve should installed at top of riser to relief air trapped.

• Downcomer pipes should be coated with primer and finished with red gloss paint.

• Pipe can be colour coded with red bands 100mm width and elbows and tees painted red.

• Riser pipe should electrically earthed.

3.4 FIRE WATER TANKS

• Fire water storage tank should be sized minimum 45 500l, automatic refill rate of 455l/min.

• Tanks maybe pressed steel, FRP or concrete.

• It should hot dipped galvanized and coated internally with bituminous for corrosion protection.

• Water tanks should compartmented unless they are reinforced concrete and ball float valves, overflow pipes, drain pipes and water level indicators should provided.

• External surface of tank should painted red white or red band 200mm should be painted to indicate it was a tank.

• Usually located on the roof to provide maximum static pressure and seperatedfrom other tank.

• It may be combine with hose reel tank when tank capacity equal to total water storage for downcomer for hose reel system.

• Hose reel tap off level should be above downcomer tap off level to reserved for downcomer.

Engineering

Dry riser system