adhesive tape or wrap a cloth around the jaws of the wrench.

Do not use a heavy steel-spring coil snake to clear traps under lavatories, sinks, or bathtubs. Use a flexible wire or spring snake that easily follows the bends in the trap. For example, a spring snake is used for clearing stoppages in floor drains. Remove the strainer or grate and work through the drain, or insert the snake through the cleanout plug opening nearest the obstruction. Stoppage clearance tools should be used with caution.

One reason why safety is so important is that a caustic chemical may have been poured into the stopped-up fixture in an effort to clear it. Caustic agents can cause serious injury if splashed into your face by a force cup. These caustic agents can also burn your hands while using a sink snake. When manually operated devices fail to clear stoppages, there are several types of chemicals that can be used to dissolve or burn them out. These chemicals are discussed briefly below.

CAUSTIC POTASH (POTASSIUM HYDROXIDE)

Stoppages can be burned out by pouring a strong solution of this chemical and hot water into the line through the fixture opening. Pour the mixture slowly into the pipe through a funnel. Since this solution can cause serious bums, personnel must wear goggles and rubber gloves. Potassium hydroxide (caustic potash) damages glazed earthenware, porcelain, and porcelain-enameled surfaces.

CAUSTIC SODA (SODIUM HYDROXIDE)

Kitchen and scullery sink stoppages are often tough problems because of grease, oil, or fat washed down along with coffee grounds and small bits of garbage into the drain. Grease congeals and acts as a binder for solid particles and can usually be cleared by successive applications of a chemical cleaner. Effective cleaners include caustic soda (sodium hydroxide) with bauxite (an aluminum compound or ore) and other ingredients to intensify their action or sodium hydroxide mixed with sodium nitrate and aluminum turnings. Adding water creates ammonia gas, which helps change grease to soap. This gas causes boiling and heating and helps dissolve the grease. When clearing a partially blocked drain, drop a small quantity of cleaner (from 2 to 8 ounces) into the open drain and follow with scalding hot water. Such cleaning agents cannot be satisfactorily used when the drain is completely plugged, since some flow is required to loosen the chemicals. A completely blocked drain must first be partially cleared with a plumber's snake before you can use the chemical cleaner effectively.

Q23. The seriousness and the nature of a stoppage determines the -type of equipment to be used. True or false?

Q24. You can use potassium hydroxide to remove a clog in PVC pipe. True or false?

SAFETY

LEARNING OBJECTIVE:

Identify procedures for safe work methods during handling, installation, and repairs of plumbing systems.

As a Utilitiesman, treat safety as part of your job. Some of the main safety precautions in plumbing are given below. This training manual does not cover all you need to know about safety. Learn all you can about safety through further study and on-the-job experience.

PIPE WORK

When acids are used in working on piping, see that they are kept in only glass or lead containers. Keep out from under hot joints while they are being poured. Ensure that hot lead is not poured over water or wet caulking.

When floors are oily and cannot be kept dry, they should be covered with sand or an oil-absorbent compound. Any type of tee, valve, or other service connection used on piping maintenance or repair should be carefully checked to make sure it is designed to withstand maximum pressure.

SEWER WORK

Before beginning plumbing work on sewer jobs, pits, or tanks that require personnel to enter a confined space, the space must be inspected by a person qualified for Confined Space Entry. Environmental or Fire Department personnel normally conduct these inspections. They will check for toxic gases, explosive atmospheres, and oxygen deficient atmospheres. After