Managing Your Water Supply

A Guide to Fire Streams and Pump Operations


   Fire Hydraulics is an introduction to the principles, variables and calculations concerned with the practical application of water as utilized in the fire service. An overview of fire characteristics, properties of water, apparatus and appliances, fire streams and hydraulic calculations will be addressed to establish a functional understanding of fireground hydraulics

Just like managing your money, you know how much you can spend. On the fire ground there is NO water credit so credit cards are out of the question. You must balance your income with your outgo. To accomplish this, you will need to know how much water you have to spend and how you intend to spend it. If you can get the water to your pump, you can deliver it in some fashion. Remember, someone is dependent on you maintaining their fire stream.

Pump operators should have a good understanding of pressure and the different kinds of pressure.

Atmospheric Pressure is the weight of a column of air at a given location on the surface of the earth. Sea level atmospheric pressure is 14.7# on the average.

Static Pressure is pressure on a confined fluid with no water flowing.

Residual Pressure is pressure remaining on a system when water is flowing.

Discharge Pressure is the pressure of the water at the point of discharge, can be nozzle pressure, pump discharge pressure or engine pressure.

As a pump operator, you should understand how to calculate engine pump discharge pressures. The standard equation use to calculate this pressure is EP=NP+FL(+/- ) ELEV.

   Succesful fire fighting depends upon adequate fire streams. An adequate fire stream may be defined as one that reaches the seat of the fire and cools the material below it's ignition point.
      One individual type fire stream at a given pressure will not always meet this demand. Consequently, there are different types of fire streams used to meet the various conditions that confront fire fighters in extinguishing fires.
      When used as an extinguishing agent, water must be released on to the burning material in order to achieve the highest extinguishing effect with the least possible water damage. Fire fighters should know how to use modern fire fighting equipment to obtain the most efficient fire streams.
      From the time a stream of water leaves the end of a nozzle until it reaches the desired point it is called the FIRE STREAM. "Fire Stream" is defined as the stream of water from the time it leaves the nozzle and passes through the air and is left to the forces of nature. The condition of the stream when it leaves the nozzle determines its condition upon reaching the desired point.
      Many factors help determine the characteristics of a stream when it leaves the nozzle. Other factors, working against them, tend to destroy the stream and diminish it's usefulness. A well-rounded compact stream leaving a nozzle at a velocity sufficient to carry it across the space between the fire fighter and the fire should be entirely effective were it not for the following factors:
  1.     friction of the air
  2.     force of gravity
      Which tends to pull the water toward the ground, causing the stream to fall far short of it's target.

   This information is presented in a format that will hopefully help you understand the limits of your equipment, give you a guide to follow when operating fire streams, and to help you best manage your water delivery systems

Pump Handbook PDF

Pump Large Diameter Hose PDF

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