By Vincent Powers

Watching the news yesterday reminded me I did not write this year’s winter prep blog. What reminded me was the snow across the country and the minus 24-degree temperatures in Minnesota.

For many states, late fall and early winter mark the transition into freezing conditions. This blog gets reposted every year for a reason, no matter how advanced systems become, cold weather remains one of the biggest threats to water-based fire protection.

Why Winter Preparation Matters

Lack of proper maintenance continues to be one of the leading causes of fire sprinkler system failures. NFPA 25, The Standard for Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, requires systems to be properly inspected, tested, and maintained year-round, but cold weather will find a weakness in maintaining the temperature of your sprinkler systems.

Unseasonable warm periods followed by sudden cold snaps, something many regions saw throughout 2024, create conditions where systems freeze unexpectedly. Frozen piping remains one of the most common winter service calls, often resulting in extensive system damage, downtime, and property loss.

Waterfilled piping is required to be maintained at a minimum ambient temperature of 40°F (4°C) and is essential to prevent freezing. Trouble spots often go unnoticed in summer but become high-risk areas in winter. Common trouble spots include, but are not limited to:

• Vestibules and entryways
• Stairwells
• Unoccupied rooms and mechanical spaces
• Attics and areas with skylights
• Poorly insulated wall cavities

Dry Pipe & Antifreeze Systems: Extra Care Required

Areas that cannot be reliably kept at or above 40°F are typically protected by dry pipe or antifreeze systems, both of which demand more frequent monitoring in the colder months.

Antifreeze Systems

Before freezing weather begins, antifreeze systems must be tested to verify that the solution protects to the anticipated minimum temperatures of the region.

If not, the system must be drained and refilled with a listed antifreeze solution that complies with NFPA 25 Section 5.3.4.

Dry Pipe Systems

The wet portion of the dry pipe valve must remain at 40°F or above.

Temperature inspection requirements:

• Daily, if the valve room depends on passive heating.
• Weekly, if equipped with an approved low-temperature alarm.

Auxiliary drains (low points) must be operated:

• After each system operation.
• Prior to freezing weather.
• As often as needed throughout winter which could be daily, weekly, or monthly depending on moisture accumulation.

NFPA 25, 2023 Annex Guidance (Still Critical in 2026)

Section A.13.4.5.3.3 of NFPA 25 emphasizes the importance of removing water from dry systems:

“Failure to keep a dry system free of water can result in damage and expensive repairs . . . Auxiliary drains should be operated on a daily basis after a dry system operation until several days pass with no discharge. . . 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.”

Auxiliary and Low-Point Drains

A typical low-point drain consists of a 1 ft (0.3 m) section of 2 in. pipe with a 1 in. valve at each end.

Operation of the auxiliary drain typically includes these steps:

1. Close the upper valve.
2. Open the lower valve and drain accumulated water.
3. Close the lower valve and reopen the upper valve to allow additional moisture to collect.
4. Repeat until water stops flowing.
5. Replace plug or cap on the lower valve.

Lessons from Recent Winters

The industry still remembers the “Big Freeze” in Texas (2021), when thousands of sprinklered buildings were put out of service.

Since then, multiple regions Midwest, Northeast, and even parts of the Southeast have experienced similar cold blasts.

Pensacola, Florida had almost 10 inches of snow in 2024.

The trend is clear: freeze events are becoming more widespread and less predictable.

This makes proper ITM more than just minimum compliance.

Final Thoughts for winter

Cold weather affects every industry, but with fire protection it can be devastating. Frozen pipes lead to ruptures, flooding, business interruption, and, worst of all, systems that cannot respond during a fire emergency.

As we head into 2026:

• Building owners must stay vigilant.
• Contractors must reinforce maintenance schedules.
• System readiness must remain a priority long before temperatures drop.

Now is the time to make sure your fire sprinkler system is prepared for whatever winter throws at it. Unfortunately, the freeze ups have already started, however it is not too late to prevent them again.

Stay warm, stay safe, and keep those systems ready for action.