Choosing a hose that meets the target flow

Published:  01 July, 2008

We tend to forget that the world is changing just a little bit at a time and as firefighters we often tend to stay the same, calling our inability to adapt, tradition.

We tend to forget that the world is changing just a little bit at a time and as firefighters we often tend to stay the same, calling our inability to adapt, tradition.
Fires have changed because of these little worldly changes. Let’s start simple. Plastics and other synthetics have become more widely used. Residential fires have changed in the past 30 years, becoming more deadly as the rate of heat release from synthetics is as much as three times that of natural products, such as wood, cotton, etc. Look around your home or fire station and see how much plastics and other synthetics are around you. Synthetics burn with dense smoke and a high heat release. A new expression for this type of fire has been coined: “black fire”. You can’t see it because of the dense smoke, but you can feel the deadly heat. Can we afford to use our same old fire attack methods and hardware for these new fires?
Take that same look around in an industrial setting. One of the most basic examples that complicates fire suppression operations are the new types of packaging materials in use. A few simple examples typify the increase in fire load over the past few years:
- synthetic pallets have replaced wood
- plastic bubble wrap and clear wrap now surrounds products
- rack storage has gone higher and higher, sometimes in huge warehouses
- plastic bottles have replaced glass in many cases, adding to the fire load of even the most benign products such as vitamins and medicines.
A more complicated example is how the world’s energy crisis has driven everyone to look for alternative fuels such as ethanol. This is a good example of how firefighters must change to adapt to the new fire hazard. We must be sure our foam concentrates and application rates are correct for the new fuel. We must be sure our hose, nozzles and appliances can meet these challenges.
Our mission
Extinguishing the fire is the most important job but as we have seen, our job and mission arecchanging and the few examples pointed out above are just the tip of the iceberg. There are a many new tools to make the job of extinguishing the fire more effective. But before we talk about what is new, let’s consider what firefighters need to make any fire attack operation a success.
First, for successful fire attack operations you must achieve your target flow every time the hose line is stretched, period. Target flow is what you want your hose lines to flow in terms of volume of water. Firefighters must be able to deliver the right amount of water quickly and effectively, usually with an undermanned engine company or brigade. The target flow must be delivered each and every time a nozzleman has the jet in his hands. Although time does not permit us to show how to conduct a flow test, it is absolutely critical to test your hose, nozzles and appliances to determine you are achieving the desired delivery of that all-important, fire-killing water.
Fire attack system
It is important to test your engine, hose and nozzles as you will use them. More importantly we should consider these tools not as single elements but as a system; a fire attack system. Here is what is needed for an effective fire attack: reliable water supply, supply hose, engine/pumper, attack hose, nozzle, pump operator and nozzle crew. All of these parts must work perfectly for an effective and safe fire attack operation.
Task Force Tips makes a great portable flow and pressure meter called a Sho-flow. Placed behind the nozzle this device will tell you how much water and at what pressure it is being delivered. It is a great asset for training pump operators and in showing and demonstrating the friction loss in hose lines.
Low pressure nozzles
Low pressure nozzles are a great boon to the fire service. Recent changes to the standard (allowing lower nozzle pressure) have resulted in manufacturers being able to supply nozzles that flow high volumes at lower pressure.
Lower pressure means less nozzle reaction, less fatigue on the always-undermanned engine company, which means more effective firefighting!
Elkhart Brass’s low pressure nozzles are a great advantage to the fire service, for example. The lower nozzle pressure at the same target flows vastly reduces nozzle reaction.
Another important advantage to lower nozzle pressure is a reduction in pump pressure, resulting in less pressure in the hose lines and less chance for a burst length. Burst lengths during the fire attack can be catastrophic, especially if that line is protecting the search and rescue teams durig an interior attack.
Many US departments are using these lower pressure nozzles with great success. As an added benefit, when additional water is needed the pump pressures can be increased resulting in large increases in volume with the same nozzles and hose.
Smooth bore nozzles are the nozzle of choice for interior fire attack for a number of well-known reasons in the US.
These nozzles are designed to flow high volumes at 50 psi nozzle pressure. Low pressure combination (fog-straight stream) nozzles operate at the same pressure. If an engine has both solid bore and low pressure combination (50 psi) nozzles, both operating at the same pressure, the pump operator does not have to know which nozzle is on a particular line, since they both operate at the same pressure. The pump operator does of course need to know the length of the line and the desired gpm, so he can calculate the correct pump pressure.
These nozzles have solved the age old question of solid bore vs fog stream or combination nozzles.
Lightweight portable monitors
As fires have become more dangerous, hotter, and going to flashover and backdraft sooner and with more deadly consequences, firefighters have added another new tool in their arsenal: the lightweight portable monitor. Usually supplied by one medium diameter hose (2 1¼2 or 3”), these flow at 500-800 gpm. Once put into play they can be left unmanned, but if the situation dictates, the monitor can be shut down, advanced or re-positioned and then opened up again.
These portable monitors are a huge advantage to firefighters, especially for industrial fires. The large volume and excellent reach of the stream provides the fire-killing punch that these fires demand. Additionally, they can be left unmanned to protect exposures – such as tanks – when it is just too dangerous to put a firefighter there. Portable monitors can also be used to cool tanks and processing towers when necessary.
Conclusion
There are many new and excellent products on the market to choose from in order to improve fire attack operations. Try them out, test them, use them to determine if they fit the needs of your department. But most of all remember that the world is changing around us, and our fire attack strategy needs to change with it.

  • Operation Florian

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