The importance of flow testing fire hydrants cannot be overstated. City water supplies depend on a regular testing schedule as a crucial component of the water supply program. One of the reasons for this is because the hydrants are constantly being exposed to degradation, usage changes, system improvements, and even maintenance activities which may have an affect on valve settings.
Testing is great for not only fire flow testing. It is also great for discovering any number of mechanical problems. These problems include anything from leaks to improperly operating valves to occasional debris flowing through the hydrants which can cause damage. A fire hydrant flow test is one of the surest ways to test the emergency capabilities of the fire hydrant system in question.
Great care must be taken when performing the flow test. This is because most municipal and district water systems use water that has been chlorinated. This can cause a dilemma if the hydrants are located next to environmentally sensitive areas of land. To counter the dangers of this, many testers will use what are known as diffuser baskets that have tablets in them which neutralize the chlorine content of the water.
Readings must be taken at several different locations. These include directly at the hydrant, where three different reads must be taken. These reading are referred to as Static, residual and pitot. This ensures the most verifiable information in regards to total flow output.
Readings must also be taken at the water main. This is done so that reserve capacity of the main can be determined. It also allows the test reader to take a hard look at lateral servings and design efficiencies.
By knowing how much water is available at each main and hydrant, fire suppression tactics can be planned more thoroughly. This is best for everyone involved as it allows the greatest factor of safety to be employed by workers whose task it is to suppress the fire. As you can see, it is in the best interest of all involved to always perform the hydrant flow test in the best manner possible.