As winter approaches in Northeast Wisconsin, building owners and facility managers turn their attention to snow removal, heating costs, and employee safety. One critical system, however, is often overlooked until a problem occurs: the fire sprinkler system. Cold weather poses a serious threat to sprinkler systems when proper winterization steps are overlooked.
Fire sprinkler systems are designed to protect lives and property, but freezing temperatures can compromise their effectiveness. According to the National Fire Protection Association, frozen piping is a leading cause of sprinkler system failure in cold climates. To address this risk, NFPA 25, the standard for inspection, testing, and maintenance of water‑based fire protection systems, outlines specific winter responsibilities for building owners.
Key winterization requirements
NFPA 25 requires annual draining of all low‑point drains, commonly known as drum drips, in dry‑pipe sprinkler systems. Extra care is needed after system testing, when water may remain trapped in piping. If not removed, that water can freeze, expand, and crack pipes or fittings. Air compressors and their tanks, which maintain pressure in dry‑pipe systems, must be maintained per manufacturer instructions.
All areas containing water‑filled piping, including valve enclosures and riser rooms, must be maintained at a minimum temperature of 40 degrees Fahrenheit. Any heat‑tracing equipment installed to protect piping should also be inspected and maintained per manufacturer recommendations. For systems that use antifreeze solutions, NFPA 25 requires verification that solution strength remains within acceptable limits.
Failure to meet these requirements increases the risk of frozen systems, accidental water discharge, and water damage. Beyond repair costs, a compromised sprinkler system may leave a building without fire protection. In these situations, local fire authorities may require a temporary fire watch until the system is restored, adding operational and staffing burdens.
Practical steps to reduce risk
Beyond code requirements, building owners can take additional steps to reduce winter‑related risks. Preventive walk‑throughs before and during cold snaps are among the most effective measures. Special attention should be given to remote or rarely visited areas such as rooms accessed only from exterior doors, storage rooms, janitorial closets, and sprinkler valve rooms. Heat sources in these spaces should be verified as operational.
Ceiling spaces also require careful attention during winter. Cold air can enter through rooflines or exterior walls, lowering temperatures above suspended ceilings and creating hidden freeze risks. Verifying insulation and airflow helps reduce cold air exposure. During periods of extreme cold, allowing warm building air to circulate into ceiling spaces, even temporarily, can help prevent freeze‑related damage. Electronic temperature monitoring adds protection by alerting operators to unsafe conditions before damage occurs.
Buildings that are vacant, partially occupied, or under construction present additional risks. Without daily occupants, issues such as broken windows or heating failures may go unnoticed until damage occurs.
An investment in prevention
Fire sprinkler systems are often out of sight and out of mind until they fail. Winterizing a fire sprinkler system is not simply a maintenance task. It is a risk management decision that protects property, operations, and the people inside the building. In a region where prolonged freezing temperatures are expected, proactive preparation remains the most reliable way to ensure fire protection systems perform when they are needed most.
About the Guest Author
Matthew Zimmerman serves as Service Sales Manager at Ahern, bringing 20 years of fire protection experience spanning system design, project management, and service. A licensed fire protection designer, he specializes in code compliance, system performance, and practical solutions for commercial and industrial facilities.
Email: mzimmerman@jfahern.com
