Process line

How to read it

P&IDs draw pipes as single lines. The DOE’s handbook says the single-line format is the one most commonly used on P&IDs, and that it shows all piping as a line whatever its size. Kuphaldt’s chart draws the process flow line heavier than the thin line of an instrument supply or process connection.

The symbol doesn’t say what the pipe carries. The DOE’s handbook notes that the process flow line doesn’t identify its medium, while the auxiliary lines beside it, for compressed air, inert gas or hydraulic fluid, have symbols that do. The details go on the line label: Woolf and others’ course notes list the pipe diameter, the service, the material and whether it is insulated.

Also searched as: process line p&id symbol, process line symbol.

Look-alikes

The thin lines around the process lines are signals and supplies: a dashed line is an electric signal, a line with pairs of slashes a pneumatic signal, and a line with small x marks a capillary tube.