Hydrants & Rising Mains Flashcards

1
Q

Purpose of Fire Hydrants

A
  • A fire hydrant is essentially a short standing pipe usually provided with two outlet connections.
  • Connected to water supply mains from which fire service pumps draw water for fighting fires in an emergency via rising mains in a building.
  • Water supply to fire hydrant is controlled by hydrant valve.
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2
Q

Provision of Fire Hydrants

A
  • Every part of a fire engine accessway of a building and/or fire engine access road to the building should be within unobstructed distance of 50m from fire hydrant.
  • Where public fire hydrant conforming to this requirement is not available, private fire hydrants should be provided.
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3
Q

How to distinguish it from a public hydrant?

A

Yellow band is usually painted on standpipe of private hydrant.

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4
Q

Factors Affecting Fire Hydrant Location

A
  • Closeness to Buildings: within 50 m from fire engine accessway
  • Closeness to Access Roads: accessible to fire engines
  • Located away from Building at Risk: preferably 6m but minimum 1m away from building so it remains useable during fire
  • No Risk of Obstruction: parking, loading & unloading of vehicles, landscaping
  • Protection from Mechanical Damage: no risk of damage by vehicles
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5
Q

Purpose of Rising Mains Systems

A
  • Rising main is a vertical pipe provided in a building for carrying water when fighting major fires.
  • Primary means by which firemen obtain large volumes of water to fight major fires on the upper floors of high-rise buildings & also in basements.
  • Also suitable for low-rise buildings with extensive floor areas.
  • Otherwise, task of laying & connecting lengths of relay hoses over large distances will be too time consuming.
  • Rising mains are fitted w landing valves at various floors from which
    firemen can connect their hose reels to draw water to fight fires.
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6
Q

Reasons for Providing Rising Mains

A

*Where building is too tall to fight fire from outside.
*Where building floor area is large.
*Where building has basements.

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7
Q

Types of Rising Main Systems

A
  • Dry Rising System
  • Wet Rising Mains
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8
Q

Dry Rising Main Systems

A
  • Normally empty of water but is capable of being charged with water for firefighting.
  • A connection, called the breeching inlet, is provided at ground level to allow fire service to pump water from fire hydrant to the dry rising main.
  • Pump is provided in fire engine.
  • Firefighter can then connect their hoses from landing valve on floor
    where the fire occurs to fight fire.
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9
Q

Dry Rising Mains: No Fire Situation

A

For all buildings, except Purpose Group I, with habitable heights greater than 10m but not exceeding 60m

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10
Q

Dry Rising Mains: Fire Situation

A
  • Permanently charged with water from a pressurised supply.
  • Pumps are installed in the building by owner & water is obtained from a suction tank installed near the pumps.
  • Hence, water is immediately available at landing valve for fighting fires.
  • Water is supplemented by firemen to suction tank via breeching inlet.
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11
Q

Provision of Type of Rising Mains based on Building Height

A
  • Dry rising mains are required in all buildings, except for Purpose Group I, where habitable height is beyond 10m but does not exceed 60m.
  • Wet rising mains are required in buildings where the habitable height exceeds 60m.
  • Dry rising mains also required to be provided to any part of a single or multiple level basement of building.
  • Separate dry & wet rising main systems are permitted.
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12
Q

Why is type of rising main used is determined by habitable height of building.

A

To avoid excessive pressures required of the pumps.

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13
Q

Required Number of Rising Mains

A
  • Any point on floor should not be more than 38m (30m of hose length plus 8m of water throw) from landing valve along a route suitable for hose lines.
  • Each rising main must serve not more than 930 m2 and all parts of the floor must be within 38m from landing valve.
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14
Q

Location of Rising Mains and Landing Valves

A
  • Rising mains & landing valves should be free from obstruction.
  • Located within smoke-stop lobbies or external corridor immediately outside door of exit staircase.
  • If got no smoke stop lobby/external corridor, it should be located inside exit staircase, or in common area & within a protected shaft, immediately outside door of the exit staircase.
  • Smoke stop lobby is protected from smoke entry & is used as staging area for fire-fighting operations.
  • All specified areas are closed to exit staircases, allowing firemen to access these areas easily.
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15
Q

Provision of Landing Valves

A
  • Provided on each rising main on every level of a building.
  • Where any part of first storey of a building, except for Purpose Group II
    buildings, is more than 38m (30m hose line length and a water throw of 8m) from breeching inlet, a landing valve at the 1st storey should be provided.
  • When one rising main is used for a floor area exceeding 930 m2, two
    landing valves needed per floor.
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16
Q

Installation of Landing Valves

A
  • Installed in a visible position where they are not obstructed by opening of doors.
  • Installed at height of 760 mm to 1000 mm above floor level.
17
Q

Automatic Air Release Valve for Rising Mains

A
  • Provided at the highest point in a rising main.
  • Allows air in rising main to escape to atmosphere when water is pumped in from ground level.
18
Q

Location of Breeching Inlets

A
  • Positioned near fire hydrants &
    protected from damage by falling glass or other debris during fire.
  • Breeching inlets are located:
    o within 18m of the access for fire engines.
    o as close as possible to the rising main.
    o in a visible position for fire fighters
    o about 760 mm to 1000 mm above ground level.
19
Q

Provision of Breeching Inlets

A
  • Must be suitable for direct coupling for the fire-fighting hose.
  • For wet rising main, the breeching inlets are connected to feed water storage tank.
20
Q

Means of Water Supply in rising mains

A
  • Water to wet rising mains is drawn from suction tank with capacity of
    at least 30 minutes.
  • Suction tanks are automatically supplied with water either directly or indirectly from water mains.
21
Q

Pumps for Wet Rising Mains

A
  • Two fire pumps, one of which is supplied from independent power source, each pump capable of providing independently the necessary water flow & pressure requirements,
  • Three fire pumps, all of which supplied from independent power source, and any two of the three pumps must be capable of providing in total, the necessary water flow & pressure requirements.
  • Standby pump is arranged so that it will operate automatically when duty pump fails.
  • Pumps must be connected to emergency power supply, if available.
22
Q

Checking and Testing of Wet Rising Mains Pumps: Four items to be checked

A
  • Duty pump can be started automatically.
  • Power supply to both duty & stand-by pumps can be changed over automatically from PUB main electrical supply to secondary power supply.
  • Duty pump can be switched over automatically to standby pump.
  • Both duty & stand-by pumps can be started manually.
23
Q

Standby Fire Hose for Rising Main

A
  • Required for every rising main except for those in buildings under Purpose Group II.

*Required length of hose is 30m & able to withstand a minimum working pressure of 15 bars.

  • Hose should be kept stowed in Dutch Rolled position & housed in a conspicuously labelled glass fronted cabinet.