Rotameter symbol
Also called Variable area flow meter
A rotameter shows flow by the height of a float in a tapered tube. It is simple and reads locally.
What the rotameter symbol means
A rotameter shows flow by the height of a float in a tapered tube. It is simple and reads locally.
How it is drawn
A tapered tube, narrow at the bottom and wide at the top, with a float inside.
The rotameter 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.
IEC 62424 has no separate symbol for this. Check the project legend.
German (DIN): Schwebekörper-Durchflussmesser. See DIN P&ID symbols.
Where you see it on a P&ID
On purge flows, small utility flows, chemical dosing and sample lines.
Tag codes
The rotameter is commonly tagged:
- FI
- FG
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 rotameter symbol look like on a P&ID?
A tapered tube, narrow at the bottom and wide at the top, with a float inside.
What is a rotameter used for?
A rotameter shows flow by the height of a float in a tapered tube. It is simple and reads locally. You will find it on purge flows, small utility flows, chemical dosing and sample lines.
What tag does a rotameter have?
It is commonly tagged FI, FG. The exact tag format comes from the project numbering procedure and the legend sheets.
Is the rotameter 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 rotameter called in German?
Schwebekörper-Durchflussmesser. 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