Frozen Pipes in Office Buildings: A Texas Hard Freeze Checklist

• Winter Storm Uri produced 510,772 insurance claims in Texas, including 44,600 commercial property claims with $4.7 billion in incurred losses, before business interruption.
• Pipes in unheated spaces start to freeze when the outdoor temperature reaches about 20°F. Water filled sprinkler piping must stay at 40°F or above.
• The riskiest spaces in an office building are the ones nobody occupies: stairwells, garages, docks, mechanical rooms, roof equipment and vacant floors.
• Never shut off a sprinkler system to stop it freezing. Under the 2026 edition of NFPA 25, piping found to contain ice is treated as an impaired system.
• The record of your rounds matters as much as the rounds. After a loss, insurers expect proof of what was checked, when and by whom.

The February 11 to 19, 2021 freeze became the largest insurance claims event in Texas history. By March 31, 2022, the Texas Department of Insurance had counted 510,772 claims and $10.4 billion in incurred losses, with the ultimate cost estimated at about $11.2 billion.

Commercial property alone accounted for 44,600 claims and $4.7 billion in incurred losses. Business interruption added another 7,206 claims and $793 million, because a burst riser does not just damage floors, it empties them.

Most of that water came from ordinary pipes in spaces nobody was watching. That is the part a building team can control.

In northern cities, pipes are routed inside the heated envelope and buildings are insulated for months of cold. Texas buildings are built for cooling, so piping often runs through spaces that are never heated at all.

Field research by the Building Research Council at the University of Illinois found that pipes in unheated spaces in southern buildings began to freeze when the outdoor temperature fell to about 20°F, and sooner where cold air moves across them, as summarized here. A Texas hard freeze reaches that in hours.

Where office buildings freeze first

• Parking garages: dry standpipes, wet sprinkler branches near openings, hose connections and domestic lines along open sides.
• Stairwells and vestibules: sprinkler piping and standpipes beside exterior walls with no heat.
• Loading docks and service corridors: doors left open, piping near the ceiling, wind driven cold.
• Roofs and penthouses: cooling towers, rooftop units, condensate lines, roof drains and makeup water lines.
• Mechanical and pump rooms: louvers, outside air intakes and fire pump rooms with failed unit heaters.
• Vacant floors and suites: heat set back or off, ceiling plenums cold, nobody walking through to notice.
• Air handlers: coils that freeze when an outside air damper sticks open or a freeze stat fails.

• 32°F for two hours: the National Weather Service issues a Freeze Warning, and a Hard Freeze Warning at 27°F or lower for at least two hours (NWS). Start your freeze plan at the watch, not the warning.
• 20°F outdoors: the point where pipes in unheated spaces typically begin to freeze.
• 40°F indoors: the minimum for any space with water filled sprinkler piping, and for the wet side of a dry pipe valve (NFSA).
• 45°F indoors: the minimum some insurers expect in occupied and vacant areas, monitored and documented (Philadelphia Insurance).
• 70°F: the room temperature the same insurer guidance sets for diesel fire pump rooms.

Most of this work takes minutes per item, but it has to happen before temperatures drop. TDI's own advice is the same: start before the freeze is forecast.

• Override energy saving setbacks and night schedules so every zone, including vacant floors, holds at least 45°F.
• Test heat trace on exposed piping, garage lines and roof lines, and confirm the controllers have power.
• Check pipe insulation in stairwells, docks and garages for gaps, crushed sections and missing fittings.
• Close and seal doors, louvers, windows and wall openings near piping; fix closers on stairwell and dock doors.
• Check air handler outside air dampers, freeze stats and low limit controls so coils are protected.
• Have your sprinkler contractor drain low points on dry pipe systems and test antifreeze solutions, as NFPA 25 expects before freezing weather.
• Confirm heat in sprinkler valve rooms, riser closets and fire pump rooms, and test low temperature alarms.
• Top off generator fuel, confirm block heaters and battery chargers work, and check the fuel supplier's winter delivery plan. Our NFPA 110 guide covers the generator checks.
• Clear roof drains and gutters so meltwater can leave the roof.
• Mark every domestic water, sprinkler and branch shutoff on a floor plan, tag the valves, and give the plan to every engineer on shift.
• Open cabinet doors under sinks on exterior walls and in tenant pantries.
• Confirm contact numbers for your plumber, sprinkler contractor, restoration company, insurer and broker.

A freeze is when rounds matter most and when staffing is thinnest, because roads are bad and people cannot get in. Plan the rounds before the storm, with names and times.

• Walk the cold spaces at least every few hours while temperatures are below freezing: garage levels, stairwells, docks, mechanical rooms, pump rooms and vacant floors.
• Read and log the temperature in each space, not just the building automation summary.
• Read dry pipe and preaction air pressure gauges; a falling reading can mean a leak or a valve about to trip.
• Look for frost on pipes, ice at drains, water on floors, dripping ceiling tiles and reduced flow at faucets, which can signal ice in the line.
• Keep doors closed and heaters running in valve and pump rooms; check portable heaters are safe and supervised.
• Never shut off or drain a wet sprinkler system to keep it from freezing. Insurers expect sprinklers to stay in service.
• If a pipe freezes, call the plumber or sprinkler contractor; do not thaw with an open flame.

Most frozen pipes burst as they thaw, so the first warm day is the riskiest. Walk the same route again before tenants return.

• Check risers, sprinkler mains and standpipes first, then domestic lines, then air handler coils.
• Have dry pipe low points drained again; ice found in sprinkler piping means the system is impaired under the 2026 edition of NFPA 25 until it is thawed or replaced and restored.
• Follow your impairment procedure for any system out of service: notify the fire department and insurer and set a fire watch.
• Photograph damage before cleanup starts, with the date, time and location of each photo.
• Keep failed fittings and burst sprinkler heads for the adjuster.
• Pull your temperature logs and round records for the storm period. They show the building was heated and checked, which is what the claim will turn on. Our guide to keeping inspection evidence for insurers covers what holds up.

1. 1. Leaving energy saving setbacks on, so vacant floors and stairwells drop below 40°F overnight.
2. 2. Trusting the building automation system for spaces it does not measure, such as garages and stairwells.
3. 3. Shutting off sprinklers to prevent freezing, which leaves the building unprotected and puts coverage at risk.
4. 4. Forgetting the garage standpipe and the roof drains because nobody occupies those spaces.
5. 5. Doing the rounds but not recording them, so there is no proof for the claim.

At what temperature do pipes freeze in a commercial building?

Pipes in unheated spaces start to freeze when the outdoor temperature reaches about 20°F, and sooner where cold air blows across them. Inside the building, keep any space with water filled piping at 40°F or above.

What temperature should a vacant office floor be kept at in winter?

At least 40°F wherever there is water filled sprinkler piping, and many insurers expect 45°F or higher, monitored and documented.

Should we drain the sprinkler system before a freeze?

No. Never take a wet sprinkler system out of service to prevent freezing. Heat the space, and have your contractor drain low points on dry pipe systems.

Does commercial property insurance cover frozen pipes?

Usually, if the building was heated and maintained. Policies commonly exclude freeze damage when heat was not maintained, and vacancy clauses can limit coverage for empty space, so keep temperature logs and round records.

How often should we check unheated areas during a freeze?

Several times a day while temperatures stay below freezing, and at least daily for vacant spaces, with each check recorded.

FacilityOps AI (RoboSkill Inc.) is an autonomous inspection platform. During a cold snap, a FacilityOps inspection robot walks the route through stairwells, mechanical rooms, pump rooms, docks and vacant space on schedule, day and night, even when engineers cannot get to the building.

On every pass it records the temperature of each space, uses thermal imaging to show cold spots and frost on piping, reads dry pipe air pressure gauges and valve positions, and photographs floors, ceilings and drains for water. Each check is stamped with the time and location, so the round itself becomes the record insurers expect.

FacilityOps sensor hubs watch known trouble spots between passes and send the robot to check when a reading changes. Findings go to the engineer who owns the system as a work order, and the next pass confirms the fix.

The robot runs fully autonomously, and technicians can take manual control at any time. Because the platform is hardware agnostic, drones, other robots or a technician's own camera can feed the same record.

The same stairwell, the same riser and the same gauge, checked on schedule through the coldest night of the year, with proof of every check.

FacilityOps documents conditions between contractor visits. It does not replace your sprinkler contractor's inspections and testing, and it does not certify compliance.

• Water Leak Detection and Water Damage Prevention for Commercial Buildings
• NFPA 25 Sprinkler Inspection and the Closed Valve Nobody Sees
• NFPA 110: Emergency Standby Power Inspections
• How to Keep Inspection Evidence for Audits and Insurers
• Fire Extinguisher Inspection and the Fire Safety Checklist for Office Buildings