Most people are aware that when water freezes, it expands. That’s why your forgotten can of soda in the freezer exploded. When water freezes in a pipe, it will expand in the same way.
If it expands enough, it will burst, water will escape and serious damage may occur. A 1/8-inch crack in a pipe can spew up to 250 gallons of water in a day. But this is one disaster you can prevent by taking a few simple precautions.
Both plastic and copper (CPVC, PEX, COPPER) pipes are susceptible to freezing. Pipes freeze for a combination of three reasons: a quick drop in temperatures, poor insulation and a thermostat that is set too low.
Water pipes in warmer climates may be more vulnerable to winter cold spells, since the pipes are more likely to be located in unprotected areas outside of the building insulation. Homeowners can be proactive by determining whether they have any plumbing items that need protection, and then ensuring that they provide that protection.
Pipes in attics, crawl spaces and outside walls are all vulnerable to freezing, especially if there are cracks or openings that allow cold outside air to flow across the pipes.
When water pipes freeze
Homeowners should be alert to the danger of freezing pipes. Any time temperatures dip to 32 degrees, pipes may freeze, especially when wind chill is a factor.
How to keep pipes from freezing
- Know where the water cut-off valve is located in your home. Make sure that every responsible person in the home is aware of its location.
- Remove, drain and carefully store hoses used outdoors.
- Keep garage doors shut if any water lines are located inside.
- Seal all openings where cold air can get at unprotected water pipes. As stated above, it’s especially important to keep cold wind away from pipes.
- Pipes in attics and crawl spaces should be protected with insulation or heat. Pipe insulation is available in fiberglass or foam sleeves. Remember, the more insulation you use, the better protected your pipes will be.
- During freezing weather, leave cabinet doors open under kitchen or bathroom sinks (especially if they are located against an outside wall) to allow warmer room air to circulate around pipes. You can also place a small lamp with an incandescent bulb near the pipes. Be sure to remove anything flammable from the area to prevent fires.
- Let faucets drip slowly to keep water flowing through pipes that are vulnerable to freezing. If the dripping stops, it may mean that ice is blocking the pipe. Keep the faucet open to assist in pressure relief.
- Heating cables and tapes are effective for freeze protection. Follow manufacturer’s directions closely when using these products.
- Exterior pipes and hose bibbs (outdoor faucets) should be drained or enclosed in 2-inch insulation sleeves.
- When weather is very cold, keep thermostats at the same temperature day and night. Lowered temperatures at night may contribute to colder attic temperatures and thus, more vulnerable pipes.
If your water pipes freeze
If you turn on your faucets and nothing comes out, the water in your pipes is probably frozen. You may be able to thaw a frozen pipe with the warm air from a hair dryer. Make sure the faucet is open, and never stand in water while operating an electric appliance. Do not use a blowtorch or any open flame to thaw a pipe, to prevent fires.
If your water pipes have already burst, turn off the water at the main shut-off valve in the house. Leave the water faucets turned on. Again, make sure your family members know where the water shut-off valve is and how to operate it. Then contact B&L Plumbing Service, Inc to help.
Thermal expansion is a relatively new problem in household plumbing systems. It is the result of installing water meters with check valves or dual check valves mandated by local and national plumbing codes. Although the purpose of the check valves is to isolate the municipal water supply from potentially contaminated household water, the resulting thermal expansion creates a separate, often under-appreciated problem.
In a typical domestic residence the largest use of potable water in the home is usually for hot water for bathing, washing, dishwashing, etc. A gas or electric water heater heats water in the domestic hot water system. The water heater uses a continuous supply of fresh water. Hot water is used at a rate dictated by the demand at the water fixtures. As hot water leaves the system through the faucets, showerheads, dishwasher, etc., fresh, cold water from the city main is supplied to the heater where it is heated for continuing use. On average, a water heater in a home will heat water two or three times a day.
When water is heated, it expands in volume by 2–3%, depending upon the initial and final temperature. This can mean as much as three or four extra gallons of water in a closed system. (If there is no demand for hot water, the expanded volume of water has no place to go.) Since water is not compressible, the expanded water cannot be accommodated in the piping system through which it travels, and therefore it creates hydraulic pressure, exerting a potentially hazardous stress on the system.
The reason this is a relatively new problem is that, until recently, most household systems were open to the municipal water supply, which meant when household water was heated it simply expanded back into the municipal supply. The situation has changed and it is becoming the norm for municipalities to enforce existing codes and regulations, requiring the installation of a dual check valve, or what is more commonly known as a backflow preventer. With the installation of a backflow preventer or water meter with a check valve that had previously been an “open” system has now become “closed” system.
It has become a “closed” system because hot water can no longer expand back into the municipal supply, and as a result, during periods when hot water is not being used, the system pressure rapidly increases until the pressure relief valve (PRV) is activated, releasing the excess water and pressure. In a typical situation, the PRV will activate two or three times a day, wasting hot water and causing premature failure of the valve, as it is only designed to activate in emergencies.
The constant over-pressurization as the result of thermal expansion creates other problems as well, such as leaking ball seals and valve stems. The most critical hazard is the potential collapse of the center flue in a gas fired water heater, allowing lethal carbon monoxide fumes to leak into the residential environment.
The first reaction of the homeowner when he or she discovers the PRV is continually discharging is to replace what he or she thinks is a faulty PRV only to find he or she has the same problem with the new valve. In some situations the frustrated homeowner wires the valve shut or completely removes it from the system, and while this removes the symptom (dripping water, etc) it eliminates an important safety device from the system, creating the potential for catastrophic failure.
Another “solution” is to connect another PRV set at a lower pressure setting and pipe it to a permanent drain. This is not a desirable solution as it continually wastes hot water, and the constant use of the PRV will eventually wear out the springs, which are not designed for such use.
The problem is permanently solved by the installation of a properly sized and pressurized thermal expansion tank. A properly installed tank will act as a reservoir for the expanded hot water and thereby maintain constant pressure. Most manufacturers offer sizing and installation information in their literature or on their web sites. Thermal expansion tanks should be UPC-Listed and not confused with heating expansion tanks, which are not designed for use with potable water.
The most common design for a thermal expansion tank for use in a residential potable hot water system has a captive air chamber, pressurized to the supply pressure at the water heater and separated from system water by a permanent flexible diaphragm. This prevents air absorption more commonly know as “water logging” which occurs when the pressurized air is absorbed into the water. The water is protected from contact with the wall of the tank through the use of a polypropylene liner. As the water is heated the expanded water is forced into the tank compressing the air cushion while maintaining normal system pressure. When hot water is used, the pressurized air cushion returns water to the system without wasting water or the energy used to heat it.
All national cross-connection codes, including the Uniform Plumbing Code (1991 edition) now require the installation of approved thermal expansion control devices. Other than new construction thermal expansion tanks are most commonly installed when backflow preventers are installed in addition, many water heater manufacturers now require installation of thermal expansion tanks as a condition of their warranty. The return on investment is easy to justify for the consumer when weighed against the potential risks.
Local water authorities charged with the responsibility of enforcing backflow prevention codes should ensure that local codes carry the wording of the model codes on mandatory requirements for thermal expansion prevention. This should be done for the protection of the water user’s life and property, and for the elimination of the water supplier’s potential liability for damage from catastrophic failure due to uncontrolled thermal expansion.
For more information or to look at our photo gallery to how to treat thermal expansion and what can happen if you do not treat it, CLICK HERE or you can give us a call at 816-347-2610. Thank you!
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