Care and Maintenance of Sprinkler Systems
Indoor sprinkler systems work in the background, and your agency only calls upon them in an emergency — that’s why maintenance is so important.
Unfortunately, even though your sprinkler system may seem ready to help, unseen corrosion inside the pipes may prevent it from working effectively (if at all) when you need it most.
PDRMA contracts with Kodiak Fire Protection Services, Inc., (KFPS) for property insurance preconstruction plan reviews for members. Daniel M. Fritz, Senior Consultant with KFPS, Inc., explains how corrosion can happen — and what you can do to prevent it — in the Q&A about sprinkler system maintenance below.
Q. How serious is internal corrosion in dry or pre-action sprinkler systems?
 A. Most dry pipe automatic sprinkler systems consist of black or galvanized steel pipes filled with air instead of water. Water condensation can collect inside the pipes and eventually result in corrosion.
If left unchecked, this corrosion can become a serious problem, resulting in reduced flow or even blockage of the sprinklers, making them ineffective when you need them during a fire. It’s also possible for extensive corrosion to cause pipe or sprinkler-head leakage that can cause water damage in your facilities.
Q. What are the warning signs that corrosion is occurring, and what is the point of no return?
A. Corrosion warning signs include:
 Rust or pipe discoloration around fittings, sprinkler heads, low point drains or valves.- Discharging of unusually dark black/brown water, sludge or particulates during sprinkler water flow or main drain testing.
- Finding water stains or drips caused by pinhole leaks in the system.
- Frequent cycling of the dry pipe system’s air compressor could mean air is escaping due to corrosion.
- Reduced water flow or pressure during system flow testing may indicate partial blockage caused by scale and corrosion.
The “point of no return” is when there is no water flow out of the sprinkler system’s inspectors test connections or low point drains, indicating complete pipe or sprinkler blockage, OR when the sprinkler pipe corrodes to the failure point and begins leaking.
Q. How can you assess the internal condition of pipes without dismantling the sprinkler system?
A. You can install a corrosion coupon assessment monitoring system — metal strips of the same material as the system piping inserted into the system and checked periodically for loss of material, pitting or corrosion. There are also other technologies such as ultrasonic inspection that can detect pipe wall thickness.
However, while these systems can be a useful tool or indicator of potential problems, they don’t tell the whole story and do not replace traditional internal pipe inspection.
Q. How often should we inspect pipes, and what constitutes a thorough inspection?
A. Per NFPA 25, Inspections, Testing and Maintenance of Automatic Sprinkler Systems, you should have a qualified contractor conduct internal pipe inspections at least every five years. If past inspections have shown significant corrosion, you should increase the inspection frequency.
An inspection does not require looking at every pipe. Your contractor should inspect a representative sample of pipes for internal scaling, pitting or corrosion, targeting any known problem areas such as low point drains.
In wet pipe sprinkler systems, your contractor should inspect any high points where air can become trapped, since the oxygen, water and steel interface can result in accelerated corrosion.
Q. What are the options if there is corrosion? Are there alternatives to pipe replacement?
 A. If you identify corrosion, scaling and debris inside the sprinkler pipe, your first step is to evaluate the severity of the situation. If severe enough, you’ll most likely have to replace the affected sections of pipe. However, in less severe cases, you may be able to flush the system to remove scale and debris and then take steps to stop further corrosion. This may include using nitrogen to inert the inside of the pipe, applying chemical treatment for microbiological activity in the water supply or installing cathodic protection.
Q. What can PDRMA members do to reduce the risk of corrosion in existing dry or pre-action systems?
A. Verify your system pipes are properly pitched and any low points where water can become trapped have a low point drain. Regularly open the drain to remove any accumulated water.
One of the most effective ways to reduce possible corrosion is to use nitrogen toinertthe dry or pre-action sprinkler system. You can install a localized nitrogen generator instead of a traditional air compressor. Nitrogen is inert and will not react with steel and water, significantly reducing the potential for corrosion.
In wet pipe sprinkler systems, you should install an automatic air vent at high points where air can become trapped, creating an air/water/steel interface. If corrosion continues to be a concern, you could install a wet pipe sprinkler system nitrogen inerting system to reduce corrosion potential.
Q. How often should agencies test sprinkler systems?
 A. At a minimum, you should have a qualified sprinkler contractor inspect and test systems annually. The inspection should include flow testing of the sprinkler system water flow alarms, two-inch main drains and private fire hydrants.
You should also physically turn and lubricate sprinkler control valves annually. Be sure to trip test any dry or pre-action-type sprinkler systems annually along with a full flow test every three years. Complete an internal sprinkler pipe inspection every five years or more frequently if you identify corrosion issues.
Q. What are your top five tips for preventive and ongoing maintenance?
- One of the most important and simple things you can do to maintain your fire sprinkler system is to conduct monthly visual inspections of the control valves and pressure gauges. It’s critical to verify the valves are in the open position and the sprinkler riser pressure gauges have adequate water pressure. This monthly inspection is simple to do but is often overlooked. Note that one of the biggest reasons for sprinkler system failure is a closed sprinkler valve.
- Inspect fire department connections annually to ensure they are accessible to the fire department, are not filled with debris, and the caps are in place to prevent tampering.
- Check fire hydrants annually to make sure they are accessible, have adequate flow and pressure, and properly drain to prevent freezing during winter months. Private fire hydrants are commonly overlooked as building owners think the city maintains them. If you are unsure about who is responsible for maintaining fire hydrants on your property, ask your fire department or public works.
- If you’re planning a building addition or renovation that includes shutting down and altering your automatic sprinkler system, use that time to conduct internal piping investigations, since the system will be out of service and available for inspection.
- After you complete your annual sprinkler system inspection, be sure to review the contractor’s report and address any deficiencies or findings of concern. At the end of the day, it’s your agency’s responsibility to ensure your buildings’ fire protection equipment is in good working condition.
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