Venturi symbol
Also called Venturi tube
A venturi tube narrows the flow smoothly and then widens it again. The pressure difference at the throat gives the flow, with little permanent pressure loss.
What the venturi symbol means
A venturi tube narrows the flow smoothly and then widens it again. The pressure difference at the throat gives the flow, with little permanent pressure loss.
How it is drawn
Two lines converging into a throat and diverging out again, in the line.
The venturi 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): Venturirohr. See DIN P&ID symbols.
Where you see it on a P&ID
On large water and gas flows where pressure loss matters.
Tag codes
The venturi is commonly tagged:
- FE
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 venturi symbol look like on a P&ID?
Two lines converging into a throat and diverging out again, in the line.
What is a venturi used for?
A venturi tube narrows the flow smoothly and then widens it again. The pressure difference at the throat gives the flow, with little permanent pressure loss. You will find it on large water and gas flows where pressure loss matters.
What tag does a venturi have?
It is commonly tagged FE. The exact tag format comes from the project numbering procedure and the legend sheets.
Is the venturi 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 venturi called in German?
Venturirohr. 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