Pipes and fittings

For transmitting fluids from one place to another we usually use a pipe. Both black and galvanized form pipes are available in the market. For the transmission of air, gas and oil, black pipes are preferred. For water transmission, galvanized pipes are preferred since they resist rusting and corrosion. Commonly used pipe construction materials are cement, asbestos, steel and cast iron. The three major varieties of pipes are cast iron pipe, galvanized iron pipe and flexible pipe. Pipe fittings such as elbow, bend, coupling, tee, union, nipple, reducer, plug etc. are made up of wrought iron. Elbow is used to make an angle between adjacent pipes. A coupling which is a short cylindrical sleeve with internal threads throughout is used for joining two pipes in a straight and bend where at least one pipe can be turned. A union is used for joining two pipe pieces, where either can be turned. Nipple which is used to make up the required length of a pipeline is a short piece of pipe with external threads at both ends. Tee is used for a single outlet branch pipe. To connect pipes of different dimensions, a reducer is used.  A plug is used to screw on to a threaded opening, for closing it temporarily. A plug is a short piece of pipe with external threads at one end and a square end on the other side.