Concentric reducer symbol
Also called Reducer
A concentric reducer joins two pipes of different sizes on the same centreline.
What the concentric reducer symbol means
A concentric reducer joins two pipes of different sizes on the same centreline.
How it is drawn
A trapezoid in the line, wide on the large side and narrow on the small side, with the two sizes written beside it.
The concentric reducer symbol in each standard
Drawn as on most US-style legend sheets.
Reducer. ISO draws one reducer symbol, a narrowing triangle, and does not separate concentric from eccentric.
ISO SVG
German (DIN): Reduzierstück, konzentrisch. See DIN P&ID symbols.
Where you see it on a P&ID
At size changes, typically around control valves, pumps and meters.
Tag codes
The concentric reducer is commonly tagged:
- e.g. 6" x 4"
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 concentric reducer symbol look like on a P&ID?
A trapezoid in the line, wide on the large side and narrow on the small side, with the two sizes written beside it.
What is a concentric reducer used for?
A concentric reducer joins two pipes of different sizes on the same centreline. You will find it at size changes, typically around control valves, pumps and meters.
What tag does a concentric reducer have?
It is commonly tagged e.g. 6" x 4". The exact tag format comes from the project numbering procedure and the legend sheets.
Is the concentric reducer symbol the same in ISA and ISO?
No. ISO draws one reducer symbol, a narrowing triangle, and does not separate concentric from eccentric. The ISO 10628-2 registration number is 516. Always check the legend sheets at the front of the P&ID set.
What is the concentric reducer called in German?
Reduzierstück, konzentrisch. On a German R&I-Fließschema it is drawn to DIN EN ISO 10628-2.
- In production since 2014
- Thousands of daily users
- On MODEC FPSO projects since 2016