How to inspect and maintain a fire hydrant
Before talking about how to inspect and maintain a fire hydrant, we can picture a scenario not uncommonly seen or heard of. An office building is on fire because of an electrical malfunction, and the fire department rushes to the building with the siren wailing. When the firefighters swiftly locate the fire hydrant and connect their hose to it, only to find that there is no water coming out. What a day!
Obviously, fire hydrant maintenance is neglected in the scenario or the real situations, which is typically a matter of life and death. Regular maintenance of fire hydrants is highly related to how well the hydrants operate. Let us first take a look at the fire hydrant operation as described below.
Fire hydrant operation
To provide water consistent and powerful enough to put out a fire, fire hydrants must be operated properly. By this we mean a hydrant wrench should always be used to operate a fire hydrant because frequent use of a pipe wrench will round off the five-sided operating nut, thus making a hydrant wrench not useful anymore.
Give the hydrant valve a few turns counterclockwise slowly, after the highest port is opened, until water reaches the open port. All debris and tiny dust in the fire hydrant barrel, if any, should be flushed out by clean water. Wait until the water is clear and slowly open the hydrant to FULL OPEN.
In so doing, the air trapped in the hydrant barrel can be expelled out of it completely. It is commonly known that the problems caused by compressed air (water is not compressible) or attached debris in the barrel will lead to the malfunction of the internal hydrant valve.
An operating hand valve should always be attached to the port where water flows out because it can be used as an alternative to the operating nut when it fails to shut down the water flow form the fire hydrant. Once the control valve is closed, the fire hydrant is shut down completely for the service team to do its repair/maintenance work.
Never allow inexperienced operators to operate aging fire hydrants, which may be left leaking when improperly closed. Worse still, inexperienced operators might damage the valve seat and bend the stem when attempting to stop the water leaks. In other words, never use a pipe, aka cheater bar, to operate aging and corroding hydrants.
Fire hydrant inspection and maintenance
As regards effective fire protection, fire hydrants’s operability and capability play crucial roles, whose success depends on systematic maintenance and regular inspection. Preventive repair and preplacement can always be scheduled to fix the problems before it is too late.
Generally speaking, at least a one-year inspection cycle should be imposed on all the fire hydrants, under which dry-barrel fire hydrants need to be inspected twice per year (a 6-month inspection cycle conducted in spring and fall).
Inspection results should be recorded in writing with problems found being reported as soon as possible. Here are the guidelines on how to maintain a fire hydrant properly:
- Check the main valve leakage by a listening device after the nozzle/pumper cap is removed.
- Check the barrel by pumping water out with a plumb bob, which will be used again a few minutes later to ensure no water is passing through the valve (recheck).
- Loosely replace the nozzle/pumper cap for air to escape before tightening the cap.
- Check the smoothness of operation by repeatedly exercising the operating stem with the hydrant fully opened. Do lubrication work or even replace the whole stem immediately if necessary.
- Check the possible leakage around the flanges, nozzles/pumpers, seals, and the operating nut when the hydrant is fully pressurized.
- Flush for 10-15 seconds after the drain outlets are opened by partially closing the hydrant.
- Relieve the pressure on the thrust bearing or packing by shutting off the hydrant then reopen it a quarter to a half turn.
- Remove foreign objects/materials by flushing the hydrant with an attached diffuser and a hand valve after removing the nozzle/pumper cap.
- Check suction pressure by placing your hand over the nozzle/pumper as the water drains out of the barrel after the hydrant is closed and the diffuser is removed.
- Lubricate nozzle/pumper caps and inspect the threads and cap chains.
- Tighten the caps after replacing them.
- Lubricate operating nuts and carry out maintenance work if needed.
- Breakaway flanges should be inspected for damage or loose bolts.
- Verify locations of the hydrants using GPS, which makes finding a snow-covered hydrant easier.
- Report to fire departments immediately on inoperable hydrants that need repair or replacement.