The scheme and operation of cold water distribution installations for fire
To combat a fire that may occur in a civil or industrial building provided a cold water distribution system, equipped with devices and fittings for training, directing and spread water flow, such as:
Hydrants outside , inside and sprinclere hydrants.
Water bodies as the jet cools causing fire burning.
Underground Hydrants (STAS 695) 70 run in diameter and 100 mm pressure of 10bar.
Is connected to the external network via a fixed flange connector body underground hydrants.
Underground hydrants are equipped with drain water to prevent freezing in winter.
Fire hoses and connections to underground hydrants through hydrants, portable cranes (STAS 697) may be two connections fixes have no shut-off valves (STAS 698) which can be single or double side.
Ground fire hydrants presents much greater reliability than underground hydrants and can be easily identified and quickly connected to water supply sources (including pumps) and fire-fighting equipment.
Number, type, location and specific flow for fire hydrants and exterior set so that the flow calculation of the water distribution pipes to extinguish a fire outside Qie (l / s) to be provided for each fire department, taking account the scheme adopted for mobile fire fighting pump or hose lines connected directly to external hydrants.
Number of external hydrants shall be such that each point of the buildings to be touched by number of jets in service simultaneously their output amounted must ensure prescribed fire water flow for each type of building.
The number of simultaneous fires that may occur outside the territories of industrial enterprises is determined as follows:
-Land-surface is less than 150ha, fire.
-Land-surface is more than 150ha, consider two simultaneous fires, choosing two buildings that require the highest water flow of fire.
Distances exterior location of fire hydrants set according to the range of hydrants, which is considered the 120m when the water pressure at hydrants required is provided by external network of 100 ÷ 150m when using pumps and 200m when using automatic pump.
In determining the location of hydrants outside distances for fire takes into account that buildings that can be protected height not exceeding 45m
Minimum pressure at hydrants that occurs outside the direct fire, should ensure the compact jets of at least 10m long, the discharge pipe acting and away the highest points of the stacks at a rate of 5 to 10 l / s.
Minimum pressure measured at the land surface from the exterior hydrants, fire intervention to ensure using mobile pumps must be at least 0.7bar.
As a result of fire hydrants can be supplied with water from external networks with hydrodynamic load at the point of connection of the hydrant, Hdisp ≥ 0.7bar.
Fire hydrants outside the network of low pressure is placed on the border 2m carriageway of the road, if the outside water supply network is located in a green area, away from the border road carriageway to the hydrants will not exceed 6m.
External fire hydrants are installed on building walls 5m surface and 10 ÷ 15m heat sources.
Exterior fire hydrants be installed at a depth of 1.25m below the depth of frost ÷ 1.5m and are served by equipment that comprises:
-Key to open your mouth water
-Handheld-hydrant hydrant valves for connection to underground
Discharge-pipe for forming and directing the water jet hole diameter of 20mm watering.
External fire hydrants are supplied with water from external networks, which can be common to those for sewage and industrial and safety are of ring operation.
Specific flow and pipe flow for calculating the size distribution outside water hydrants
Specific flow
At one outdoor fire hydrant shall be deemed 5l / s.
Water flows for fire fighting outside the civil buildings Qie isolated hospitals and administrative buildings are social-normative data.
Flow calculation for water networks that supply industrial enterprises are taken into account by the number of fires that can occur simultaneously on their territory.
In determining simultaneetatilor and duration of operation of different systems of protection are taken into consideration the following:
- If the installation is interior and exterior hydrants is considered the usual construction, operation hydrants inside for 10 minutes, and those outside these 3 hours.
The high block buildings, in the first hour to ensure the operation or the hydrants inside either the exterior installation dimensionandu to the largest flow, and these only 2:00 of the exterior.
Fire water requirements can be provided by expanding the distribution network in that city populated center of the distribution network and its own reserves or only from its own reserves.
Hydrants shall be provided with external systems for underground parking with more than 20 cars.
If networks do not provide satisfying water flow and pressure conditions required for fire water reserve sized according NP086/05.
Solutions to achieve the installation of fire hydrants outside
External fire hydrants can be:
-Underground hydrants
-Surface-hydrant
Pipes that are placed outside fire hydrants have the following minimum diameters:
-100mm hydrants Dn 65mm sau Dn80mm
-150mm for hydrants Dn100mm
-250mm for hydrants Dn150mm
External fire hydrants shall be equipped with accessories for the passage of water according to fire safety scenarios prepared for the worst situations in the project adopted and mentioned in the instructions.
External water supply networks in which flows and pressures available to ensure the possibility of direct intervention in case of fire, the fire hydrants outside, fitted with accessories in accordance with rules
These accessories can be stored in boxes attached to the walls of the building or mobile carts rooms housed in the fire service.
Water jets made by fire hydrants must reach all points outside of buildings protected combustible, considering the range of hydrants depending on the length of hose:
-Maximum 120 m from water supply networks to ensure the required supply pressure directly from hydrants..
-150 M when using motopompelor
-200 M when using autopompelor
Number, type, location and flow distances specific for exterior fire hydrants shall be designed, flow calculation of water distribution pipe for fire fighting outside Qie [l / s] to be provided for each compartment fire, taking into account the scheme adopted for mobile fire fighting pump or hose lines connected directly to external hydrants.
Number of external hydrants shall be such that each point of the buildings to be touched by the number of jets in service simultaneously their output amounted must ensure prescribed fire water flow for each type of building.
A fire will return to an area inhabited by more than 10 000 inhabitants.
In determining the location of hydrants outside distances to fire will also take into account that the heights of buildings that can be protected shall not exceed 45m.
Minimum pressure in fire hydrants which occurs outside of direct fire, should ensure the development of compact jets with a minimum of 10m length, discharge pipe acting and away the highest points of the roof or stacks with a capacity of 5 ÷ 10 l / s.
Mounting external fire hydrants
Mounting external fire hydrants
For connection to the hydrant water supply pipe is mounted on a tee or welded it ramificatie.Inainte mounting a check if the hydrant is in working order and if it closes normally-open, if discharge hole is not clogged and if there are rubber gasket between flanges with fabric insert.
Grease hydrant rod with grease at the point of friction occur.
Hydrant foot rests on a block of concrete poured directly into the ditch.
The role of this block is not to allow movement down the hydrant during operation.
To absorb water that flows from the hydrant to the closure, drainage runs, three buckets of gravel poured into the right outlet..
Hydrant is mounted on concrete block, checking the verticality of the body and is connected to pipe water. During the test, is based hydrant short wooden ball, not moving.
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