Thermoplastic piping is being used for water distribution piping within buildings and for water service lines. These two areas of application are somewhat different so that when freezing occurs, they can be treated in the following ways:

Building Distribution Piping:
When freezing occurs within the wall or in the crawl space, thawing should be done as soon as possible since complete freezing, may in some cases, cause the pipe to rupture. Since the flexible plastic piping will not rupture due to freezing, simply wait until it thaws.

Several methods of thawing may be used depending on the accessibility of the pipe and the availability of the devices. The plastic material used in the pipe can be determined by reading the markings on the pipe line, and pipes made of CPVC and PB may be heated to 180°F. All other piping should be limited to 150°F and the pipe temperature can be judged by grasping it firmly with the bare hand. For most people, 150°F is the maximum acceptable hand contact temperature. Do not pour boiling water on the pipe! Do not use an open flame heating source!

The following methods of applying heat have been used successfully:

1. Expose the piping in the area of which the freeze has occurred as much as possible and direct a small fan into that area to circulate warmer air from the occupied space into the wall cavity, in which the pipe is frozen.
2. If the frozen section of pipe is accessible, wrap it with a cloth saturated with hot water. As the cloth cools, remove; dip again in hot water and rewrap.
3. If the frozen section of pipe is fully or partially accessible, blow heated air directly on the area where freeze occurred utilizing a low capacity heater/blower such as a hair dryer.

Water Service Lines:
If there is an outside underground water meter, this should be checked first because it may be the point at which freezing has occurred. If there is reason to believe that the meter is frozen, call the Utility Department for assistance.

Buried pipe should always be installed well below the frost line. However, if a buried line freezes and the condition is localized, the pipe can be exposed and then thawed with hot water. If the exact location of the ice plug cannot be established, and the line terminates in a basement or crawl space, it may be possible to cut the line there and feed a small diameter tube into the pipe. By pouring or pumping warm or hot water into the small tube, it is possible to melt the ice plug.

The ice plug can also be melted with a resistance-heating element inserted into the pipe from the basement or crawl space as above. Take a 3/8" or 1/2" diameter rodtype DC resistance heating element and fasten it securely to an electricians steel fish tape. Connect two insulated wires to the heating element leads and cover these connections with insulating tape and then apply a water tight tape wrap or a shrink fit sleeve. Bind the wires to the fish tape at about 2' intervals. Feed the element and fish tape into the service line until the element hits the ice plug. Connect electrical wires to battery to provide DC current to the element. The heating element will melt through the ice plug as it is moved forward. Continue to penetrate ice plug until flow is established. If penetration is stopped, pull the tape and element back. Do not leave them in the pipe.

Obviously, other techniques for thawing can be devised, but the most economical method is prevention. Thermostatically controlled heat tapes may be useful for permanent protection in certain areas if insulation does not provide adequate protection.

NOTE:
This PPFA User Bulletin is designed to provide guidance in achieving the efficient, effective and informed use of plastic pipe. The suggestions and advice obtained in this Bulletin are offered merely to provide plastic pipe users with a general frame of reference. Because specific situations may, and often do require special treatment, the suggestions and advice are obviously not universally applicable. Therefore, the user should carefully assess the requirements of his specific situation before making practical application of anything contained in this publication.