The specification, a general note, or bill of material will list the types of connections such as flanges, unions, or couplings and whether the fittings are flange or threaded. A general note or specification is used to describe the type of connection.ĭetachable connections are shown by a single thick line (Figures 5-6 and 5-7). Permanent connections, whether made by welding or other processes such as gluing or soldering, should be shown on the drawing by a heavy dot (Figure 5-6). They are generally used for catalogs and similar applications where visual appearance is more important than drawing time. An example of a double-line pictorial pipe drawing is shown in Figure 5-4. Single-line drawings take less time and show all information needed to lay out and produce a piping system.ĭouble-line pipe drawings require more time to draw and therefore are not recommended for production drawings. The center line of the pipe is drawn as a thick line to which the valve symbols are added. A single-line isometric picture-based drawing of Figure 5-1 is illustrated in Figure 5-3. Single-line drawings show the arrangement of pipes and fittings. The finished drawing is easier to understand in the picture-based format. Picture-based projection is used for all pipes bent in more than one plane, and for a device made up of smaller parts and layout work.

This method also may be used for more complicated piping systems. Single- and double-line orthographic pipe drawings (Figures 5-1 and 5-2) are recommended for showing single pipes either straight or bent in one plane only. Isometric projection is used to show a three-dimensional view of an object in single plane. Orthographic projection is used to show multiple views of an object in a single plane.

Two methods of projection used in pipe drawings are orthographic and isometric (pictorial). A set of symbols has been developed to identify these features on drawings. Piping drawings show the size and location of pipes, fittings, and valves. For these reasons contractors, manufacturers, and engineers should become familiar with pipe drawings. Piping is also used as a structural element in columns and handrails. The age of atomic energy and rocket power has added fluids such as liquid metals, oxygen, and nitrogen to the list of more common fluids such as oil, water, gases, and acids that are being carried in piping systems today. Today almost every conceivable fluid is handled in pipes during its production, processing, transportation, and use. Water was at one time the only important fluid that was moved from one point to another in pipes.

How to read isometric piping drawings