Fire Protection Training: Fire Streams

A fire stream is a stream of water or other extinguishing agent after it leaves a fire hose and nozzle until it reaches the desired point.

Fire streams are intended to reduce high temperatures from a fire and provide protection to firefighters and exposures through the following methods:

* Applying water or foam directly to burning material to reduce its temperature.

* Applying water or foam over an open fire to reduce the temperature, so fire fighters can advance hand line closer to effect extinguishment.

* Reducing high atmospheric temperature.

* Dispersing hot smoke and fire gases from a heated area by using a fire stream.

* Creating a water curtain to protect firefighters and property from heat.

Water has extinguishing properties with its ability to extinguish fire in several ways. The primary way is by cooling, which removes the heat from the fire. Another way is by smothering, which includes water’s ability to absorb large quantities of heat and also to dilute oxygen.

Water when you put water a fire or smoldering object creates steam.

The steam produced by a fire stream can be an aid to a fire extinguishment by smothering, which is accomplished when the expansion of steam reduces oxygen in a confined space.

Several characteristics of water that are extremely valuable for fire extinguishment are as follows:

* Water is readily available and inexpensive.

* Water has a grater heat-absorbing capacity than other common extinguishment agents.

* Water changing into stream requires a relatively large amount of heat.

* The greater the surface area of the water exposed, the more rapidly heat is absorbed.

To produce effective fire streams, it is necessary to know the effects of factors affecting pressure loss and gain. Two important factors that affect pressure loss and gain in a fire stream are friction loss and elevation. Pressure changes possible due to friction loss in a hose and appliances. A loss or gain in pressure may result due to elevation and direction of water flow up hill or down hill.

Friction loss is defined as that part of total pressure that is lost while forcing water through pipe, fittings, fire hose, and adapters.

One point to consider in applying pressure to water in a hose line is that there is a limit to the velocity or speed at which the water can travel. If the velocity is increased beyond the limits, the friction becomes so great that the water in the hose line is agitated by resistance. Certain characteristics of hose layouts such as hose size and length of the lay also affect friction loss.

In order to reduce pressure loss doe to friction, consider the following guidelines.

- Check for rough linings in the hose
- Replace damaged hose couplings
- Eliminate sharp bends in hose when possible
- Use adapters to make hose connections only when necessary
- Keep nozzles and valves fully open when operating hose lines
- Use proper size hose gaskets for the hose selected
- Use short hose lines as much as possible
- Use larger hose (for exp. Increase from booster hose to 1 ¾ hose or from 1 ¾ hose to 2 ½ hose) or multiple lines when floe must be increased Reduce the amount of flow (for exp. Change nozzle tips or reduce flow setting)

Elevation refers to the position of an object above or below sea level. In a fire fighting operation, elevation refers to the position of the nozzle in relation to the pumping apparatus which is at ground level. Elevation pressure refers to a gain or loss in a hose line caused by a change in elevation. When a nozzle is above the pumper there is a pressure loss, when the nozzle is below the pump, there is a pressure gain, these losses and gains occur because of gravity.

When the flow of water through fire hose or pipe is suddenly stopped, a surge is referred to as water hammer. Water hammer can often be herd as a distinct sharp clank, very much like a hammer striking a pipe. This sudden stopping results in a change in the direction of energy. This energy creates excessive pressure that can cause considerable damage to water mains, plumbing, fire hose, hydrants, and fire pumps.

SHUT OFF NOZZLES, HYDRENTS, VALVES, AND HOSE CLAMPS SLOWLEY TO PREVENT WATER HAMMER.

A water fire stream is identified by its size and type. The size refers to the volume of water flowing per min; the type indicates a specific pattern of water. Fire streams a classified in to three different sizes: low-volume streams, hand line streams, and master streams. The rate of discharge of a fire stream is measured in gallons per min(GPM) or liters per min(L/min)

- Low-volume stream-discharges less than 40gpm including those fed by booster hose lines
- Hand line stream-supplied by 1 ½ to 3inch hose which flows from 40 to 350gpm nozzles witch flows in excess of 350gpm are not recommended.
- Master stream- discharges more than 350gpm and is fed by multiple 2 ½ or 3 inch hose lines connected to a master stream nozzle. Master streams are large-volume fire streams.

A solid stream is a fire stream produced from affixed orifice, smoothbore nozzle, it is designed to produce a stream as compact as possible with little shower or spray. It has the ability to reach areas that other streams might not be able to reach, minimize the chance of steam burns to fire fighters and better penetration to the fire It can be affected by gravity, friction of the air, and wind.

When solid stream nozzles are used as hand lines they should be operated at 50psi. Used as a master stream should be operated at 80 psi.

Advantages:

- Solid streams maintain better visibility for firefighters than other types of streams.
- Have grater reach than other types of streams.
- Operate at a reduced nozzle pressure per gallon than other types of streams thus reducing the nozzle reaction.
- Have grater penetration power than other types of streams.
- Less likely to disturb normal thermal layering of heat and gases during interior structural attacks then other types of streams.

Disadvantages:

- Do not allow for different stream patterns.
- Can not be used for foam applications.
- Provide less heat absorption per gallon delivered than other types of streams.

CAUTION: Do not use solid streams on energized electrical equipment. Use fog patterns with at least 100psi nozzle pressure. Do not use wand applicators because they can be conductors.

A fog stream is a fire stream composed of very fine water droplets. The design of the fog tip is to produce different stream patterns from the nozzle. The idea of the fog nozzle is to expose the maximum water surface for heat absorption. Fog nozzles permit settings of straight stream, narrow-angle fog, and wide-angle fog. REMBER LEFT FOR LIFE RIGHT FOR FIGHT.

There are five factors that affect the reach of a fog nozzle:

- Gravity
- Water velocity
- Fire stream pattern selection
- Water droplet friction with air
- Wind

Fore water flow adjustment, it is often desirable to control the rate of water flow through a fog nozzle such as when the water supply is limited. Two types of nozzles provided this capability: manually adjusting and automatic nozzles.

Manual adjusting nozzles: you can adjust the nozzle flow by turning the dial on the nozzle

Automatic nozzles: you can adjust the nozzle flow by opening and closing the valve.

CAUTION: Water flow adjustments in manual and automatic for nozzles require close coordination between the nozzle person, the company officer, and the pump operator.

Advantages:

- The discharge pattern of fog streams may be adjusted to suit the situation
- Some fog nozzles have adjustable settings to control the amount of water being used
- Fog streams dissipate heat by exposing the maximum water surface for heat absorption

Disadvantages:

- Fog streams do not have the reach or penetration power of solid streams.
- Fog streams are more susceptible to wind currents.
- Fog streams may contribute to fire spread create heat inversion, and cause steam burns to firefighters when improperly used during interior attacks.

Maintenance of nozzles:

- Check the swivel gasket for damage or wear replace worn or missing gaskets.
- Look for external damage to the nozzle.
- Look for internal damage and debris. When necessary, thoroughly clean nozzles with soap and water using soft bristle brush.
- Check for ease of operation by physically operating the nozzle parts. Clean and lubricate and moving parts that appeared to be sticking according to manufacture’s recommendations.
- Check to make sure that the pistol grip is secured to the nozzle.

(The usual disclaimers: I am not a journalist; This is a blog that expresses an outlook and is not conclusive in any shape or manner.)