Causes of Hydrant Damage
- Combining brass, commonly found in fire equipment or internal portions of the hydrant, with the main body of cast iron or steel in the fire hydrant causes electricity to move through the system, causing electrolysis. Though it's commonly used in electroplating, it also causes significant damage, essentially causing corrosion to start on the hydrant. This can happen when the stem and operating nut rust together, where the brass stem sleeve joins to the steel upper stem, the steel lower stem and the brass drain valve, and the seat ring compression area where the brass seat ring and the cast iron hydrant elbow meet.
- As one of the most common causes of hydrant damage, vehicle accidents can cause serious problems for your hydrant system. Whether the accident causes small cracks, bolts that are broken, stems that are bent or the breakaway flange is damaged, preventing accidents that can damage your hydrants can help keep them in operation without expensive repairs. This can be as simple as including a flag on your hydrants to mark their location for snowplows or general traffic.
- In dry barrel fire hydrants, which are used in much of the northern areas of the country, if a valve fails to seal properly, the water either continues to flow into the barrel or fails to drain out, depending on exactly how the valves are failing. In this case, the water that remains in the barrel can freeze in cold weather, blocking vital water from flowing into the hydrant when it's attempted to be operated by emergency services. By regularly testing your dry barrel hydrants, you can often catch leaking valves before they become a problem in the cold months of the year.
Too Much Force with Incorrect Tools
- The amount of force that is used on your hydrants can cause damage to them in many situations, If your fire department is done with a fire and are shutting the valve, the water is still flowing, because debris in the system is blocking the valve. Do they stop to exercise the valve to release the debris, after a long, exhausting night of firefighting? Or do they crank down on the operating nut to see if it will close with more pressure, damaging the valve in the process? Too often, the latter is the choice that is made.
Results of Hydrant Damage
Imagine a small town on a winter's evening. There's a cold snap expected, and the heaters are running furiously to keep the cold at bay. Whether it's a worn extension cord run dangerously beneath a rug to prevent tripping hazards, an overloaded circuit or an ancient heater that suddenly malfunctions, a fire breaks out.
Emergency services are called, and the fire department responds to the fire. There's still someone in the house, so they're in a hurry to limit the damage and get that person out. They try to remove the caps from one hydrant, but it was cross-threaded last time it was sealed up, and the crew can't get the cap off. A second hydrant has frozen up due to a faulty drain valve, and a third has a heavily-stripped operating valve, making it difficult to operate the hydrant.
Because none of these hydrants were properly maintained by the time a functional hydrant is found and connected, the entire structure was ablaze. The job of rescuing the individual still in the house has become that much more difficult and dangerous. How much time could have been saved if the hydrants had been properly maintained and marked if out of service?
How to Inspect a Hydrant
Hydrants need to be inspected at least annually, with dry-barrel fire hydrants requiring two inspections annually, typically in the spring and fall. However, to meet ISO standards, there are a number of other details that need to be attended to in addition to twice-yearly inspections. These include:
- Location and number of the hydrant and that it is facing the proper direction with a minimum 15" clearance from the lowest outlet to the ground.
- Any physical damage or defect to the hydrant, as well as the condition of the paint and that it has the proper color code.
- The hydrant's status as a public, private or non-potable, its static pressure reading with date and time.
- Any obstructions on or around the hydrant, if it has a visible auxiliary valve and whether the outlets have been cleaned and lubricated.
There are some specific questions to consider while inspecting the hydrant:
- Are there any leaks during a static pressure test, can you hear the main valve leaking when using a listening device or is there standing water around the base of the hydrant? Does it drain properly?
- Is the hydrant in a dangerous position near traffic that requires relocation or bollards to be installed to protect it? Is it plumb or has it been struck by a vehicle? Do the pumper port and nozzles face the right direction and does it need to be raised or lowered to permit ease of use? Typically, the nozzles should be between 18" to 24" from the ground and should have 3' of clearance in every direction.
- Is it difficult to operate? Are the nozzle and pumper threads in proper working condition or do they need maintenance or replacement? Does it provide sufficient flow for firefighting? Is the paint in good condition and the correct color for your utility's requirements?
- Does it look like the hydrant has been operated illegally? If so, do you need to consider adding protective devices to deter vandalism or illegal usage?
Here are the steps for a proper hydrant inspection:
- Remove one of the nozzle or pumper caps and use a listening device to listen for leakage in the main valve. Check the barrel for water or ice using a plumb-bob. Pump the water out of the hydrant's barrel, wait a few minutes and then check that water has not leaked through the valve.
- Put the cap back on, but leave it loose enough for air to get out. Open the hydrant valve so that the air can vent out of the loosened cap, then tighten the cap the rest of the way and open the hydrant fully. Is it easy to operate? If necessary, exercise the operating stem several times to free up buildup and make it operate more easily. If it needs to be lubricated or the stem replaced, put it on the work schedule.
- Check for leaks around the flanges, nozzles, pumpers, seals and the operating nut. Close the hydrant partially so that you can open the drain outlets, then flush it for 10-20 seconds. Close the hydrant completely, then open a quarter to half turn so that pressure on the thrust bearing or packing is relieved.
- Remove one of the nozzles or pumper caps (if possible, a different one that previously used to check it for functionality). Attach a diffuser if necessary and a hand valve to control the outflow. Flush the hydrant thoroughly to flush out foreign material, checking the water quality in a plain white cup. Continue flushing until you have good water quality.
- Once you're done flushing it, close the hydrant and remove the diffuser, putting your hand over the nozzle or pumper to check for suction while the water drains out on a dry barrel hydrant or pump the water out on a wet barrel hydrant. Again using a listening device, check for leakage in the hydrant. Remove and lubricate all of the nozzle and pumper caps, inspecting the threads for damage.
- Check that the cap chains have ease of movement, unbinding or replacing them as needed. Replace and tighten all of the caps. Determine whether the operating nut needs lubrication or maintenance. Check whether the breakaway flange has been damaged. Collect or verify that the hydrant's GPS location is recorded properly. If a hydrant needs repair or replacement, immediately have it added to the workflow.
By undertaking the semi-annual inspections of your water utility's hydrant assets, you'll be able to incorporate much of the preventative maintenance into the same process. Regular testing and checking the movement of the nozzles or pumper caps and operational valve ensures that these vital components will work when they're needed. Checking for leakage in the main valve means that the hydrant won't freeze up when the fire department needs to use it.
When these steps are followed, you can ensure that the system will operate properly or that appropriate maintenance can be scheduled to make repairs as needed. If a hydrant needs maintenance, tag it out with an out of service sign so that firefighters don't waste precious during an emergency on a hydrant that is inoperable.
Difference between Wet Barrel and Dry Barrel Hydrants
With different structures and different fire fighting procedures, dry and wet barrel hydrants are used in different parts of the country. But what's the real difference between them? Here's a quick overview to get you started.
Wet Barrel Hydrants:
- Wet barrel hydrants have a sturdy, basic design that allows them to operate for well over 100 years. The mechanism is all above ground, with the main valve preventing debris from entering the hydrant. Outlet valves and nozzles are independent, allowing firefighters to add lines to it without shutting the hydrant down to do so. However, these aspects also mean that this type of hydrant is very susceptible to frost, which is why they're typically used in the hot regions of the southern US but not in the northern reaches of the country.
Dry Barrel Hydrants:
- Unlike the wet barrel's upper main valve, the dry barrel's main valve is seated at the base of the hydrant. Because this keeps the water line entirely below the frost line, this type of hydrant is much more prevalent in northern climates. When the valve is opened, the water fills the barrel, pressurizing it, and when the valve is closed, the water drains out, eliminating the risk of freezing.
Tools for the Job
If you need help getting on top of your hydrant maintenance program, Team EJP can help. We stock a number of quality tools and our hydrant maintenance service takes the task off of your to-do list entirely. Please feel free to contact us today to get started.