Water has been used as an extinguishing agent ever since fire was discovered. There wasn’t much science to promote its use; people just figured out it worked.
Of course, we now know why it is so effective and the choice for extinguishment in the majority of hostile fires. It is readily available, relatively inexpensive, and effective. Not to discount the importance of low cost and access, the fact that water is very effective when applied makes it the best option in most cases.
CAPABILITIES
The effectiveness is attributed to its properties. Water has the ability to cool environments, absorb heat when converting from liquid to gas, and expel oxygen and other gases because of its tremendous expansion as it enters the gas state of matter. Looking at it from a simplistic view considering the fire triangle, water helps in all aspects of extinguishment. Heat, fuel, and oxygen are needed to have combustion. Water helps reduce the heat below ignition temperatures because of its ability to absorb heat. It can contribute to the smothering of a fire from its rapid expansion that will produce about 1,600 times the volume when in a gaseous state vs. a liquid. So, for every gallon of water that converts to steam, there will be 1,600 “gallons” of gas. This will help to force out oxygen, which lowers the amount needed to sustain combustion. The expansion will also help replace flammable gases.
This simple explanation is intended to get you more in tune with the capabilities of water as an extinguishing agent and understand why it is so important to move the water from a source to the fire as quickly as possible and with as much as possible, depending on conditions and supply. The fire service has done a very good job of developing methods to move the water. Some have been through trial and error, some science, and some lessons learned from experience. Some of the properties of water have created challenges, such as its freezing point of 32°F. The more that is understood, the better chance of properly applying the water.
SOURCE
Moving water from a source to the fire involves hoses, a pump, appliances, and people. For areas with good water supply systems, the source is rarely a stumbling block. But in cold weather climates, maintenance of hydrants becomes important. The maintenance may also affect operation: If routine maintenance is not done, it can lead to “frozen” hydrants—those that don’t open because of corrosion, rust, or some other reason. Connecting to the water source should be an automatic operation. Of course, in some communities some of the hydrants are not standardized.
I once worked in a community where a few hydrants had different threads and some had different size outlets; in a few private systems, there was never any certainty. Suffice it to say, a sound and basic knowledge of the system is very important.
PEOPLE
Regardless of the source, hose, or equipment, people are needed to maximize efficiency and effectiveness. From the pump operator to the pipe man, there need to be knowledge,