Part 3

REPAIRING LEAKS IN PIPES AND TANKS

Pipes

Leaks in pipes usually result from corrosion or from damage to the pipe. Pipes may be damaged by freezing, by vibration caused by machinery operating nearby, by water hammer, or by animals bumping into the pipe. (Water hammer is discussed on P. 8)

Corrosion

Occasionally waters are encountered that corrode metal pipe and tubing. (Some acid soils also corrode metal pipe and tubing.)

The corrosion usually occurs, in varying degrees, along the entire length of pipe rather than at some particular point. An exception would be where dissimilar metals, such as copper and steel, are joined.

Treatment of the water may solve the problem of corrosion. Otherwise, you may have to replace the piping with a type made of material that will be less subject to the corrosive action of the water.

It is good practice to get a chemical analysis of the water before selecting materials for a plumbing system. Your State college or university may be equipped to make an analysis; if not, you can have it done by a private laboratory.

Repairing Leaks

Pipes that are split by hard freezing must be replaced.

A leak at a threaded connection can often be stopped by unscrewing the fitting and applying a pipe joint compound that will seal the joint when the fitting is screwed back together.

Small leaks in a pipe can often be repaired with a rubber patch and metal clamp or sleeve. This must be considered as an emergency repair job and should be followed by permanent repair as soon as practicable.

Large leaks in a pipe may require cutting out the damaged section and installing a new piece of pipe. At least one union will be required unless the leak is near the end of the pipe. You can make a temporary repair with plastic or rubber tubing. The tubing must be strong enough to withstand the normal water pressure in the pipe. It should be slipped over the open ends of the piping and fastened with pipe clamps or several turns of wire.

Vibration sometimes breaks solder joints in copper tubing, causing leaks. If the joint is accessible, clean and resolder it. The tubing must be dry before it can be heated to soldering temperature. Leaks in places not readily accessible usually require the services of a plumber and sometimes of both a plumber and a carpenter.

Tanks

Leaks in tanks are usually caused by corrosion. Sometimes, a safety valve may fail to open and the pressure developed will spring a leak.

While a leak may occur at only one place in the tank wall, the wall may also be corroded thin in other places. Therefore, any repair should be considered as temporary, and the tank should be replaced as soon as possible.

A leak can be temporarily repaired with a toggle bolt, rubber gasket, and brass washer, as shown in figure 6. You may have to drill or ream the hole larger to insert the toggle bolt. Draw the bolt up tight to compress the rubber gasket against the tank wall.

WATER HAMMER

Water hammer sometimes occurs when a faucet is suddenly closed. When the flow of water is suddenly stopped, its kinetic energy is expended against the walls of the piping. This causes the piping to vibrate, and leaks or other damage may result.

Water hammer may be prevented or its severity reduced by installing an air chamber just ahead of the faucet. The air chamber may be a piece of air-filled pipe or tubing, about 2 feet long, extending vertically from the pipe. It must be airtight. Commercial devices designed to prevent water hammer are also available.

An air chamber requires occasional replenishing of the air to prevent it from becoming water-logged--that is, full of water instead of air.

A properly operating hydropneumatic tank, such as the type used in individual water systems, serves as an air chamber, preventing or reducing water hammer.

FROZEN WATER PIPES

In cold weather, water may freeze in underground pipes laid above the frostline or in pipes in unheated buildings, in open crawl spaces under buildings, or in outside walls.

When water freezes it expands. Unless a pipe can also expand, it may rupture when the water freezes. Iron pipe and steel pipe do not expand appreciably. Copper pipe will stretch some, but does not resume its original dimensions when thawed out; repeated freezings will cause it to fail eventually. Flexible plastic tubing can stand repeated freezes, but it is good practice to prevent it from freezing.

Preventing Freezing

Pipes may be insulated to prevent freezing, but this is not a completely dependable method. Insulation does not stop the loss of heat from the pipe--merely slows it down--and the water may freeze if it stands in the pipe long enough at below-freezing temperature. Also, if the insulation becomes wet, it may lose its effectiveness.