Thermowell symbol
Also called TW, Temperature element
A thermowell is a closed tube inserted into the line or vessel that protects a temperature element and lets it be removed without opening the process.
What the thermowell symbol means
A thermowell is a closed tube inserted into the line or vessel that protects a temperature element and lets it be removed without opening the process.
How it is drawn
A small circle or a short line into the pipe, tagged TW or TE.
The thermowell 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): Schutzrohr. See DIN P&ID symbols.
Where you see it on a P&ID
At every temperature measurement point.
Tag codes
The thermowell is commonly tagged:
- TW
- TE
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 thermowell symbol look like on a P&ID?
A small circle or a short line into the pipe, tagged TW or TE.
What is a thermowell used for?
A thermowell is a closed tube inserted into the line or vessel that protects a temperature element and lets it be removed without opening the process. You will find it at every temperature measurement point.
What tag does a thermowell have?
It is commonly tagged TW, TE. The exact tag format comes from the project numbering procedure and the legend sheets.
Is the thermowell 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 thermowell called in German?
Schutzrohr. 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