- October 2014
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Knowing how and when to prepare your pipes for cold weather can help prevent needless inconvenience and even avert a catastrophe. The average insurance claim for household water damage due to ruptured frozen water pipes is over $10,000. That amount represents more than just repairing damage to the structure. The inundation of water due to a ruptured frozen supply line may ruin personal belongings that no amount of insurance can replace.
The aftermath can include long-term effects like the growth of toxic mold, as well as other unpleasant side effects. Learn how to prepare your pipes for cold weather before you get that first freezing forecast so you’ll be ready to act.
How Cold Is Freezing?
Inside a water pipe, ice doesn’t form the minute outdoor temperatures dip to 32 degrees. Latent heat in water shielded by a pipe requires colder temps. Studies by the University Of Illinois have found that the threshold for pipe freezing is actually around 20 degrees. This finding was verified by surveys to plumbers who reported the highest number of frozen pipe service calls when temperatures dropped to that level.
However, since different conditions, such as structural openings that allow frigid outside air to directly contact water supply lines, may accelerate heat transfer out of the water, a safer level to prepare your pipes for cold weather is 28 degrees.
Why Pipes Burst
Since ice expands, it was long assumed that radial pressure from expanding ice inside pipes was the force that caused ruptures due to freezing. Studies have shown, however, that ice formation breaks pipes through a different mechanism. As freezing occurs, the ice expands laterally, applying pressure to the water inside the pipe on either side of the ice plug. Water in the pipe upstream of the ice can always move backward into the city water line. However, water downstream from the ice has nowhere to go and is placed under extreme pressure. The resultant increase in water pressure, not the ice itself, actually causes the rupture.
Before Cold Weather Strikes
As part of fall maintenance, prepare your pipes for cold weather. First identify water supply lines that are located in unconditioned zones of the house such as the attic, garage or crawl space.
- Install pipe insulation sleeves on all accessible spans of hot and cold water pipes in these areas.
- Install faucet insulation on faucets outdoors.
- Seal cracks or gaps in exterior walls or the foundation that may allow a flow of cold outdoor air to contact water supply lines. Use caulking for small openings or expandable polyurethane spray foam for larger holes.
- Check the sump pump pit for debris and verify proper automatic operation of the pump. Make sure the sump discharge pipe is properly located so residual water will drain from the pipe and not freeze.
When Freezing Temperatures Are Imminent
- Outside, disconnect garden hoses and remove residual water from each. If your home has indoor valves to shut off water to faucets, turn the valve off and open the faucet to allow excess water to drain.
- Close vents leading to crawl space and garage vents.
- Increase the movement of warm air inside the house to keep pipes inside walls warm. Maintain the household temperature at 55 degrees or more around the clock. Open the doors of cabinets under sinks and closets to help circulate warm air.
- Open faucets in sinks and bathtubs to allow a continuous trickle of cold water overnight as long as dangerous temperatures persists. This permits damaging water pressure that might occur from ice formation inside pipes to escape and prevents rupture. The stream of water should be slightly less than the thickness of a pencil.
During the Freeze
Be alert to possible signs of a frozen pipe. If you open a faucet and no water comes out, or if you begin to notice unexplained drops in water pressure, call a professional plumber immediately. DIY efforts to thaw frozen pipes at best produce uncertain results, and at worst they could be dangerous. If you’re sure of the frozen section, you can apply commercially-available UL-approved heat tape designed to warm pipes. Be careful of using devices like hair dryers that aren’t designed for that purpose due to the hazard of electrocution. Never use an open flame such as a propane torch to thaw a frozen pipe.
To prepare your pipes for cold weather or get professional help for a frozen pipe, contact Meyer’s.
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