[ RESOURCES ] / SYMBOLS / PIPING ISOMETRIC SYMBOLS
Piping isometric symbols
27 symbols for piping isometric drawings: welds and joints, fittings, valves and the annotations that place the line in the plant, each with what it means and what is checked on site. Free to download as SVG, or as a printable chart.
How to read a piping isometric
Start with the title block and the north arrow, then follow the line from one end to the other:
- Joints: a dot for a butt weld, a cross or FW for a field weld, two lines for a flanged joint.
- Fittings: elbows, tees, reducers, blinds, each with an item number in the bill of materials.
- Valves: the same bodies as on a P&ID, with their flanges and handwheel direction. See gate valve.
- Annotations: dimensions, slopes, offsets and the continuation to the next sheet.
The full walk-through is on how to read a piping isometric.
Which standards isometric symbols follow
ISO 6412-2 sets the rules for isometric projection of pipelines. Most isometrics are generated from the 3D model, with symbols set by the software and the project, so the project legend always governs.
For the process view of the same line, see the P&ID symbols; for the welds, the welding symbols.
Using these symbols
Every symbol on this page was drawn by Deskely. You are free to use them in your own drawings, documents and training material.
Frequently asked questions
What are piping isometric symbols?
The symbols on a piping isometric drawing for joints, fittings, valves and annotations: a dot for a butt weld, two lines for a flanged joint, the valve bodies, the north arrow, slopes and offsets.
What does a dot mean on an isometric?
A butt weld. Unless it is marked as a field weld, it is a shop weld made in the fabrication shop.
How is a field weld shown on an isometric?
As a cross, an open circle or a dot labelled FW, depending on the project. FFW marks a field fit weld, with extra length left for cutting on site.
What does a hatched triangle mean on an isometric?
A rolling offset: a leg that runs off the three main directions. The hatching shows the plane it lies in.
Can I use these symbols in my own drawings?
Yes. The symbols on this page were drawn by Deskely and are free to use in your own drawings, documents and training material.
- In production since 2014
- Thousands of daily users
- On MODEC FPSO projects since 2016
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