Pipe Drawings

When drawing pipes at a large scale, they are shown as in Figure 388. Pipe fittings may vary slightly depending on the manufacturer.

For smaller drawings or sketches, simple symbols like those in Figure 389 are used. A single thick line represents the pipe, no matter its size, to make it stand out from other lines. Pipe layouts usually follow orthographic projection (Figure 390A), which means showing the pipe from different straight-on views. But sometimes, it’s easier to flatten everything into a single developed view (Figure 390B). Another option is using isometric or oblique drawings (Figure 390C) to show the pipes in 3D, either by themselves or along with other drawings.

Important Rules for Pipe Drawings:

Always measure from the centerlines of pipes, valves, and fittings so they can be placed correctly.
Let the pipe fitter handle small adjustments when putting everything together.
Show how much space is needed for fully open valves and other pipe equipment.
List pipe sizes in a note using their nominal diameter instead of writing dimensions on the pipes themselves.

Other Tips:

Clear notes are important so that anyone reading the drawing understands it.
When drawing pipe threads and threaded holes, some drafters make them straight, while others show them slightly tapered to be more noticeable.