Eccentric reducer symbol
Also called FOT reducer, FOB reducer
An eccentric reducer changes the pipe size with one side kept straight. Flat on top (FOT) avoids trapping gas; flat on bottom (FOB) lets the line drain.
What the eccentric reducer symbol means
An eccentric reducer changes the pipe size with one side kept straight. Flat on top (FOT) avoids trapping gas; flat on bottom (FOB) lets the line drain.
How it is drawn
A taper with one straight side. The straight side shows whether it is flat on top or flat on bottom, and FOT or FOB is usually written beside it.
Isometric SVGWhere you see it
Pump suctions (usually flat on top, so no vapour pocket forms) and pipe racks where the bottom of pipe must stay level.
What is written next to it
On the isometric, the eccentric reducer usually carries an item number, the two sizes and FOT or FOB.
What gets checked on site
For a eccentric reducer, the site checks usually cover the welds and, above all, the orientation: an eccentric reducer installed upside down is a common punch item. Each check is recorded against the line and the joint, so the line can go into its test pack and be handed over with its evidence. See the ITR guide.
Related symbols
Frequently asked questions
What does the eccentric reducer symbol look like?
A taper with one straight side. The straight side shows whether it is flat on top or flat on bottom, and FOT or FOB is usually written beside it.
Where is a eccentric reducer used?
Pump suctions (usually flat on top, so no vapour pocket forms) and pipe racks where the bottom of pipe must stay level.
- In production since 2014
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- On MODEC FPSO projects since 2016