How to Prevent Frozen Pipes in Commercial Buildings: 10 Winter Checks
Most frozen pipes start in the cold spots nobody walks through: unheated stairwells, loading docks, exterior walls and lines on heat trace. Check those spots before the first hard freeze and keep checking them all winter. One split pipe can mean flooded ceilings, ruined equipment and days of cleanup. This guide covers the 10 checks to make before December, where to look, and how often to recheck once the cold sets in.
Quick Answer: Winter Freeze Checklist at a Glance
| Check | Where | When |
|---|---|---|
| Heat trace and controllers | Roof drains, outdoor lines, docks | Before December, then weekly in cold weather |
| Freeze stats / low limits | Air handlers with outside air | Before December |
| Unheated spaces | Stairwells, docks, penthouses, crawl spaces | Before December, then on cold nights |
| Air leaks | Doors, dampers, louvers, penetrations | Before December |
| Dry sprinkler low points | Drum drips and auxiliary drains | Before first freeze and during cold weather |
| Outdoor water lines | Hose bibbs, irrigation, fountains | Before first freeze |
| Pipe insulation | Exterior walls, above ceilings, chases | Before December |
| Sump pumps and backflow | Pits and outdoor devices | Before December |
| Shutoff valves | Mains and zones | Before December, then yearly |
| Cold-night plan | Whole building | Before the first forecast freeze |
Why Do Pipes Freeze Before the Coldest Night?
Most frozen-pipe calls don’t come from the coldest night of the year. They come from a door that was propped open, a heat-trace circuit nobody tested since spring, or a stairwell nobody walks through. The fix is a planned walk-through before the first hard freeze, done the same way every year.
Here are the 10 checks we’d put on the schedule this month, in the order most teams can knock them out.
1. How do you check heat trace before winter?
Check that every heat-trace controller has power, reset any tripped ground-fault protection, and confirm the cable is warm where it should be.
Heat trace fails quietly. Check that each controller has power and its indicator lights are on, reset any tripped ground-fault protection, and confirm the cable is actually warm where it should be. Look for damaged insulation or missing end seals on outdoor runs. Write down which circuits protect which lines, so the next person doesn’t have to trace them in the dark.
2. How do you know if a freeze stat is working?
Trip it on purpose and make sure the air handler shuts down or closes its outside-air damper, and that the alarm reaches someone.
A freeze stat that doesn’t trip lets frozen outside air wreck a coil in one night. Verify the setpoint, test that the unit shuts down or closes its outside-air damper when the stat trips, and make sure the alarm reaches someone. Pay extra attention to units that bring in a lot of outside air.
3. Where do pipes freeze first in a commercial building?
Pipes usually freeze first in unheated or rarely used spaces such as stairwells, loading docks, mechanical penthouses and crawl spaces.
Stairwells, loading docks, mechanical penthouses, crawl spaces, vestibules and storage rooms freeze first. Turn on the unit heaters and confirm they run. Leave a cheap thermometer in the spots that worry you, and add them to the cold-night walk-through list.
4. How do air leaks cause frozen pipes?
Cold air moving across a pipe freezes it much faster than still air, so open doors, broken closers and leaky dampers are a common cause.
Cold air moving across a pipe freezes it faster than still air. Fix broken door closers, replace worn weatherstripping, check that dampers and louvers close all the way, and seal wall and roof penetrations near water lines. A propped-open dock door has frozen more sprinkler pipe than any cold snap.
5. Do dry sprinkler systems need to be drained in winter?
Yes, the low points on dry-pipe sprinkler systems collect condensation and should be drained before the first freeze and during cold weather.
Dry systems still collect condensation at low points (drum drips and auxiliary drains). Drain them before the first freeze and again during cold weather, following NFPA 25 and your fire protection contractor. The dry-valve room needs heat too, so confirm its heater works. Our fire sprinkler checklist covers the full inspection.
6. Should outdoor water lines be shut off for winter?
Yes, shut off and drain hose bibbs, irrigation lines and outdoor fountains before the first freeze.
Close the interior valves to hose bibbs, irrigation lines and outdoor fountains, then open the outside fixtures to drain them. Disconnect hoses. A hose left connected keeps water in a frost-free hydrant and can split it.
7. Which pipes need extra insulation in winter?
Pipes along exterior walls, above ceilings near outside walls, in soffits and in unheated chases need the most attention.
Look above ceiling tiles near outside walls, in soffits and in unheated chases. Replace missing or wet insulation and close the gaps where cold air gets in. Mark these spots on your floor plan so they get checked every winter.
8. Do sump pumps and backflow preventers need winter checks?
Yes, run each sump pump through a full cycle and make sure outdoor backflow preventers are insulated or heated.
Run each sump pump through a full cycle and check its alarm. Outdoor backflow preventers need an insulated enclosure or heat. If a device sits on a seasonal line, drain it per the manufacturer and your water utility’s rules.
9. Why should every shutoff valve be labeled before winter?
When a pipe bursts at night, the crew needs to find and close the right valve in minutes.
When a pipe bursts at 2 AM, minutes matter. Tag every main and zone shutoff, exercise the valves so they turn, and post a simple map in the maintenance shop. Make sure night and weekend staff know where the valves are, not just the day crew.
10. How do you keep pipes from freezing during a holiday shutdown?
Set a cold-night plan: assign who walks the building, set low-temperature alarms, and don’t let empty spaces get too cold over a long break.
Decide who walks the building when temperatures drop well below freezing, on weekends and during holiday shutdowns. Set low-temperature alarms in the building automation system, and don’t let setbacks drop empty spaces too low over a long break. Put the walk-through on the schedule as a recurring work order, so it happens even when the person who usually does it is out.
How Does a CMMS Help Keep Winter Freeze Checks on Schedule?
A CMMS turns the winter walk-through into a recurring work order, so it shows up on the same date every year with the checklist attached. No one has to remember it, and it doesn’t depend on the one person who has always done it.
- Recurring PMs: schedule the pre-winter walk-through and the cold-weather rechecks as preventive maintenance work orders.
- Checklists on the work order: heat trace, freeze stats, dry sprinkler drains and shutoffs are checked off on a phone or tablet in the mobile browser.
- A record of what was found: notes and photos stay with each asset, so next year’s crew knows which spots froze before.
- Problems become work orders: a damaged insulation run or a failed unit heater gets its own work order instead of a sticky note.
That’s how eWorkOrders customers keep seasonal checks from slipping.
Frequently Asked Questions
When should we start winter freeze checks?
Before the first forecast hard freeze, which for most of the country means November. Finish the walk-through before December, then repeat the short checks (heat trace, unheated spaces, dry sprinkler drains) during cold spells.
Where do pipes freeze first in a commercial building?
In unheated spaces and along exterior walls where cold air moves across the pipe: stairwells, loading docks, vestibules, mechanical penthouses, soffits and above ceilings near outside walls. Dry sprinkler low points and outdoor hose bibbs are also common trouble spots.
How do we make sure freeze checks happen every year?
Put them on the schedule as a recurring preventive maintenance work order with a checklist attached. That way the checks show up on the same date each year and you have a record of who did them and what they found.
What should we do if a pipe freezes but hasn’t burst?
Know where the shutoff is before you start, open a faucet downstream, and warm the pipe slowly with safe heat such as a heat gun on low or warm towels. Never use an open flame. If you can’t reach the frozen section, call a plumber.
Can a CMMS track winter freeze checks?
Yes. A CMMS can schedule the pre-winter walk-through as a recurring work order with a checklist, keep notes and photos with each asset, and turn anything found into a repair work order.
Final Thoughts
Freeze-ups are rarely bad luck. Walk the building before December, fix the air leaks, test heat trace and freeze stats, and put the walk-through on the schedule so it happens every year.
Keep Every Job on Schedule and On Record
Use our free facilities maintenance checklist for the full walk-through, and keep every check on schedule with eWorkOrders. eWorkOrders has supported maintenance operations for over 30 years, serving teams at Honda and King River Packaging, rated 4.9 on Capterra and G2.
Statistics are also summarized on our Maintenance & CMMS Statistics page. Standards and codes change; always follow the current edition your authority having jurisdiction requires and the equipment manufacturer’s instructions.
About the author: Janet Jaquis is Marketing Director at eWorkOrders, where she writes about maintenance strategy, asset reliability, and CMMS software for maintenance and facility teams.
