Hydrants & Rising Mains Flashcards
Purpose of Fire Hydrants
- 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.
Provision of Fire Hydrants
- 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.
How to distinguish it from a public hydrant?
Yellow band is usually painted on standpipe of private hydrant.
Factors Affecting Fire Hydrant Location
- 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
Purpose of Rising Mains Systems
- 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.
Reasons for Providing Rising Mains
*Where building is too tall to fight fire from outside.
*Where building floor area is large.
*Where building has basements.
Types of Rising Main Systems
- Dry Rising System
- Wet Rising Mains
Dry Rising Main Systems
- 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.
Dry Rising Mains: No Fire Situation
For all buildings, except Purpose Group I, with habitable heights greater than 10m but not exceeding 60m
Dry Rising Mains: Fire Situation
- 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.
Provision of Type of Rising Mains based on Building Height
- 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.
Why is type of rising main used is determined by habitable height of building.
To avoid excessive pressures required of the pumps.
Required Number of Rising Mains
- 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.
Location of Rising Mains and Landing Valves
- 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.
Provision of Landing Valves
- 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.