Level gauge symbol
Also called Sight glass level gauge, LG
A level gauge shows the liquid level directly, through glass or with a magnetic float indicator, with no signal sent.
What the level gauge symbol means
A level gauge shows the liquid level directly, through glass or with a magnetic float indicator, with no signal sent.
How it is drawn
A tall narrow rectangle beside the vessel with two connections, tagged LG.
The level gauge symbol in each standard
Drawn as ISA 5.1 defines it, as on most US and international legends.
ISO 10628-2 does not cover instruments. On ISO-based P&IDs they are drawn as IEC 62424 PCE requests, or to ISA 5.1 on many international projects.
German (DIN): Standanzeiger. See DIN P&ID symbols.
Where you see it on a P&ID
On vessels, tanks and boilers for local level checks.
Tag codes
The level gauge is commonly tagged:
- LG
- LI
Tag formats follow the project numbering procedure. For instruments, the letters follow ISA 5.1, explained on the instrument symbols page.
Related symbols
Frequently asked questions
What does the level gauge symbol look like on a P&ID?
A tall narrow rectangle beside the vessel with two connections, tagged LG.
What is a level gauge used for?
A level gauge shows the liquid level directly, through glass or with a magnetic float indicator, with no signal sent. You will find it on vessels, tanks and boilers for local level checks.
What tag does a level gauge have?
It is commonly tagged LG, LI. The exact tag format comes from the project numbering procedure and the legend sheets.
Is the level gauge symbol the same in ISA and ISO?
ISO 10628-2 does not cover instruments. On ISO-based P&IDs they are drawn as IEC 62424 PCE requests, or to ISA 5.1 on many international projects. Companies vary the details, so always check the legend sheets at the front of the P&ID set.
What is the level gauge called in German?
Standanzeiger. On a German R&I-Fließschema it is drawn to DIN EN ISO 10628-2 and DIN EN 62424.
- In production since 2014
- Thousands of daily users
- On MODEC FPSO projects since 2016