Fire trucks can supply the needed water to put off the small fires. For bigger fires using the local underlying water pipe network can be a good and reasonable solution. So for this purpose in high risk area, safety engineers consider a special connection (pipe with valves and outlets) on the pipe lines of water distribution system which called fire hydrant. To put it simply, fire hydrant is a pipe with valves and outlets which provide a water for firefighting. Fire fighters only need to attach their hoses to the outputs of the hydrant and open it!
Hydrants have one or more outputs for different flow rates. Usually minimum flow rate is 945 litre per minute.
Hydrant types based on installation:
There are many different types of hydrants which the most commons are as below:
- Above ground: positioned at the street level.
- Under ground: connected to the water pipe line directly.
- Break away
- Tunnel (garden hydrant)
Hydrant types based on pressure:
1- Pressurized
- Dry barrel (riser): hydrant is connected to water source directly and each outlet has a separate valve.
- Wet barrel (riser): hydrant is separated from water source with one main valve and normally there are no other valves on the outlets.
2- Unpressurized
Hydrant connection types:
Fire hydrant connection type must be compatible with common hoses in fire trucks which used by fire fighters in that area.
- Threaded
- Storz
- Other special connections
What is the stand pipes and their difference with hydrants?
Operation of stand pipes is also like hydrants but with below differences:
- Hydrants typically placed outside of the buildings and stand pipe for internal access of fire fighters inside the buildings. Meanwhile there is a special stand pipe in fire trucks for intermediary connection of underground hydrants.
- Hydrants are installed vertically but stand pipes are used for both horizontal and vertical positions.
Note1: Installation of hydrants must be according to standards and local regulations.
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