Lack of proper maintenance is one of the leading reasons fire sprinkler system failure.  Fire sprinkler systems shall be properly Inspected, Tested, and Maintained (ITM) in accordance with NFPA 25, The Standard For Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, Systems exposed to cold weather are especially vulnerable.

During cold months, these systems are more susceptible to catastrophic failure.  Frozen sprinkler pipes are one of the more common service calls throughout winter months. Maintaining a minimum of 40 degrees (F) is imperative in ensuring the sprinkler pipes do not freeze.  Many areas that go unnoticed during the summer can create issues in cold months, these areas include but not limited to entry ways (vestibules) and stairwells, unoccupied spaces, skylights, and areas that are not properly insulated.

Sprinklered areas that cannot be maintained at 40 degrees (F) or above are usually protected with a dry pipe or antifreeze system. These types of systems may require more thorough assessments and routine maintenance to keep the systems from freezing.   Antifreeze systems should be tested prior to the onset of freezing weather to verify that the antifreeze solution will protect to the anticipated temperatures for the region the system(s) are installed.  If they cannot protect to the required temperatures, they should be drained and provided with new premixed antifreeze meeting the requirements of NFPA 25, section 5.3.4.

Wet portions of the dry pipe valve must be maintained at a minimum of 40 degrees (F) and the enclosure must be inspected daily to verify minimum temperature is maintained and weekly if the room is equipped with a low temperature alarm. The low point and auxiliary drains are required to be drained after each operation of the system, before the onset of freezing weather, and as needed after that.  How often these drains shall be operated throughout the cold season will depend on how much condensation is the drain. This could be a daily, weekly, or monthly requirement based on existing system and building conditions.

NFPA 25 (2020) A 13.4.5.3.2- Removing water from a dry system is an essential part of a good maintenance program. Failure to keep the dry system free of water can result in damage and expensive repairs to both the system and the building.  A program for monitoring the condition of the system and the operation of the auxiliary drains should be instituted. Auxiliary drains should be operated on a daily basis after a dry sprinkler system operation until several days pass with no discharge of water from the drain valve.  Thereafter it might be possible to decrease the frequency to weekly or longer intervals depending on the volume of water discharged. Likewise, when preparing for cold weather, the auxiliary drains should be operated daily with the frequency of operation decreasing depending on the discharge of accumulated water. In many cases, the frequency of the operation can decrease significantly if a system is shown to be dry. A quick-opening device, if installed, should be removed temporarily from service prior to draining low points.

Procedure for draining a drum drip drain.

1. Close upper valve.
2. Open the lower valve, and drain the accumulated water.
3. Close the lower valve, open the upper valve, and allow for additional water accumulation.
4. Repeat this procedure until water ceases to discharge.
5. Replace plug or nipple and cap in lower valve.

Other types of valves may be installed and used as auxiliary and low point drains that are not a drum drip type drain in the dry pipe sprinkler system.  This type of drain will require a more involved process than a drum drip to drain the water.  Your fire protection contractor should be consulted for the proper procedures in draining this type of drain.

Cold weather causes issues in all industries, in the fire protection industry it can wreak havoc.  When not properly maintained fire protection systems can freeze, burst, and fail to function entirely if needed. It is extremely important to ensure that these systems are properly maintained to ensure they are ready to operate in the event of an emergency.