How is the enriched water column defined by a fire hydrant?
The effective range of fire water flow is usually expressed in a full water column. The full water column of a water gun is the jet from the exit of the nozzle, up to 90% of the total jet flow through the diameter of the 38cm circle, and the length of the dense, non dispersed jet. The experimental data statistics, radiant heat fire firefighters that can not close the ignition point, therefore, from the gun nozzle flow, should have sufficient range to ensure the fire flow required to reach. When the length of the water column of the water gun is too large, the counterforce of the jet will make it impossible for fire fighters to grasp the water cannon and extinguish the fire, so that the length of the water column should not be larger than 15m. All types of buildings require water cannons to enrich the length of the water column, and can be chosen according to the table when they are designed.
Building water supply and drainage, wrote: "water guns in the diameter of 26~38cm round section, containing all the water 75%~90% dense water column length, called the full length of the water column.". The length of the water column ranges from 7 to 15 meters (including 7 and 15 meters). Less than 7 meters, difficult to approach the fire source, greater than 15 meters, recoil force is too large. Fire water writes: "enriched water column" means the amount of water from the nozzle to the dense jet, 90% of which passes through a dense jet at the diameter of 38cm. "Fire code for building design" GB50016-2014 pointed out that: water jet from the water jet nozzle, 90% of the water column through the diameter of 380mm round hole at the length of a jet.
26~38cm water column (Full 75%~90%) refers to the water cannon in the round section of the diameter, containing all the water volume of the dense water column length, called the length of the enriched column. Represented by Hm.
