Relief valve symbol
Also called PSV, Safety valve
A relief valve opens at its set pressure to protect the line or equipment. It is an angle valve: the inlet comes from below, the outlet leaves to the side.
What the relief valve symbol means
A relief valve opens at its set pressure to protect the line or equipment. It is an angle valve: the inlet comes from below, the outlet leaves to the side.
How it is drawn
An angle body with the inlet below, the outlet to the side and a spring on top, flanged at both ends.
Isometric SVGWhere you see it
Overpressure protection of vessels, pumps, lines and heat exchangers.
What is written next to it
On the isometric, the relief valve usually carries the instrument tag, such as PSV-101, and the inlet and outlet sizes and ratings.
What gets checked on site
For a relief valve, the site checks usually cover the tag and set pressure, and that it is removed or blinded during the pressure test of the line. Each check is recorded against the line and the joint, so the line can go into its test pack and be handed over with its evidence. See the ITR guide.
Related symbols
Frequently asked questions
What does the relief valve symbol look like?
An angle body with the inlet below, the outlet to the side and a spring on top, flanged at both ends.
Where is a relief valve used?
Overpressure protection of vessels, pumps, lines and heat exchangers.
- In production since 2014
- Thousands of daily users
- On MODEC FPSO projects since 2016