materials  and  the  equipment  used  are  presented below. Cast-Iron Pressure Pipe (For Water Mains) The  cast-iron  pipe  used  for a water distribution system is somewhat different from that used for waste systems. Some of the major differences are in the length of the pipe, the joints, and the lining. Cast-iron soil pipe for waste, as you know, comes in 5-foot and 10-foot lengths. Cast-iron pressure pipe for water mains comes in 20-foot lengths with either bell-and- spigot  or  mechanical  (gland-type)  joints.  This  pipe may be coated with coal-tar pitch or be cement-lined; however, uncoated pipe is available if needed for other purposes. MEASURING  AND  CUTTING.—Cast-iron pressure pipe is measured by the inside diameter; a ruler or tape is frequently used for measuring. With a cement  lining,  the  lining  goes  beyond  the  inside diameter of the pipe, so you have to allow for this reduced inside dimensioning. To cut cast-iron water pipe to the desired length, use either a hand-operated chain cutter or a power hacksaw. Because of the construction of this pipe, it does not need reaming after cutting; but, you can use a file to dress down the cut when necessary. FITTINGS. —Three major types of fittings for joining  cast-iron  pipes  in  water  service  are  tees, elbows, and couplings. Since these fittings look like those used for sewer lines, a detailed description need not be provided here. JOINING.—In  water  service  lines,  bell-and- spigot cast-iron pipe is joined with lead, lead wool, or sometimes a sulfur compound. Specially prepared treated paper may also be used. Before making a joint, you should first check each length of pipe for cracks or splits. After eyeing the pipe for  defects,  rap  it  with  a  hammer.  With  a  little experience, you will know the difference between a good pipe and a bad pipe (cracked or split). Next, wrap the yarn around the spigot end, place it in the bell of the previously laid length, then straighten and adjust it with a yarning iron. Use enough yam to fill the joint within approximately 2 inches of the face of the bell. Then clamp a joint runner in place around the joint, so it fits tightly against the outer edge of the bell. The lead should then be poured into the V-shaped opening left at the top by the clamped joint runner. This 3-29 lead fills the space between the yam and the runner. This joint must be made in one pouring for best results. After the lead has hardened (about 10 seconds), the runner is removed, and the lead, which shrinks while cooling, is expanded by caulking until it makes a tight fit. Caulking requires skill; hammer blows that are too heavy could split the bell, or blows that are too light could leave a loose joint. Lead wool is lead in shredded form that does not require melting. Lead wool is sometimes used when water is encountered in a trench. In this process, more yarn is used; the joint is filled to about 1 inch of the face of the bell. Lead wool requires more time in caulking than poured lead. A sulfur compound is melted on the job, like lead, but at a lower temperature. It is then poured into a joint prepared for a cast-lead joint. The fact that it is light in weight is its primary advantage. It requires no caulking and provides a strong joint that is unlikely to blow out. Initially, joints of sulfur compounds leak or sweat slightly, but they tighten up in a short time. Since the joints are rigid, they should not be used to connect a newly laid line to an old one, as the settlement of a new line can cause a crack. A lead joint should be used at the connection. Mechanical joints are made with rubber sealing rings held in place by metal follower rings bolted to the pipe. This type of joint is designed to permit expansion and contraction of the pipe without injury to the joints. Copper Pipe Copper pipe and tubing with soldered joints or flared-tube connectors are used for water service. Copper is highly regarded because of its corrosion- resistant  properties,  flexibility,  ease  of  installation, and low resistance to flow throughout its useful life. Three types of copper, designated as Types K, L, and  M,  are  commonly  used.  Type  K  is  used  for underground  service  and  general  plumbing;  Type  L  for general plumbing; and Type M with soldered  fittings only. Types K and L copper come in either straight 20- foot lengths of hard temper or in coils of 50 to 100 feet, soft temper. Type M comes in straight 20-foot lengths, hard drawn only. Another type of copper, Type DWV (drain, waste, and vent), is used only in aboveground soil, waste, and vent lines. It is furnished in hard temper only and in sizes from 1 1/4 to 8 inches. It is available in 12-foot lengths as well as the standard 20-foot lengths.