What Are Some Commonly Used Symbols for Piping Drawings?

What Are Some Commonly Used Symbols for Piping Drawings?

Common symbols used in piping drawings include function symbols, such as two circles, side-by-side, indicating instrument sharing in common housing and a diamond with a P in the middle indicating a purge or flush device. Pipe- and valve-end symbols include a curved 90-degree angle opening to the right with one smaller vertical line on each side, which represents a screwed pipe, or two triangles, vertically tip-to-tip with straight lines extending from their bases, which stands for screwed valve.

Flow symbols include a circle containing the letters FE with a line extending from the bottom of the circle, looking like a balloon on a string, that floats slightly above a horizontal line. The horizontal line usually contains a shape at its center, such as a square containing an open triangle pointing to the right, the full symbol in this case representing a vortex sensor.

Line symbols used in piping design drawings include a straight line, representing an instrument supply or connection to process and a straight line with three diagonal, right-leaning lines intersecting it at equal distances, indicating an undefined signal. A straight line with three Ls intersecting it, equal distance apart, indicates a hydraulic signal. A straight line with three equally spaced Xs intersecting it indicates a capillary tube and with three S shapes intersecting it horizontally, an electromagnetic or sonic signal.