To:
Subject: Ring gasket evaluation.

Question:

How should I evaluate a ring gasket?  I know it should have a smooth surface condition, but if it has some handling damage, how much damage does it take to disqualify its utilization? Can I reuse a gasket? Could you provide some photographs with a reference to scale?

Answer:

Many operators make a serious effort to preserve and protect ring grooves in flanges. They seem to do this because of awareness that a damaged and rusted ring groove will not allow a seal and costs substantially to repair. Operators pay less attention to ring gaskets even though they constitute half of any ring joint connection seal.

The photographs below, of BX-152 S4 ring gaskets, show (left to right) a new undamaged gasket, an unused gasket with handling damage, and a used gasket with clearly visible coined sealing areas.

Click on a Ring Gasket image to see an enlarged view with information about the condition of the example in the photograph.

New undamaged gasket.   Unused ring gasket with handling damage.   Used ring gasket with “coined” sealing surfaces.

New undamaged BX-152 gasket.
The O.D. and I.D. edges of this gasket show no visible damage. Installation of this gasket into a “satisfactory” pair of ring grooves between flanges or hubs, should produce a leak free seal after connection tightening. Small serrations (machine marks), discoloration or very light rust should not affect sealing. Use steel wool or fine grade emery cloth to remove light rust if necessary before use. Stainless steel ring gaskets do not rust but may discolor.

Click here to see Field Appraisal of Ring Grooves

Unused BX-152 ring gasket with handling damage.
This unused ring gasket has somehow received damage on one of its O.D. sealing surfaces. The damage constitutes a dent or “ding” that crosses the surface that must “coin” to seal. This gasket, if used, will almost certainly leak. ¹ This damage may have occurred by mishandling at any time after final inspection by the manufacturer. Merely dropping the gasket accidentally can cause damage like that shown. BX ring gasket design specifically intends the gasket to seal on its’ O.D. Any damage to the O.D. “corners” beyond minor scratching or discoloration may cause leakage.

Click here to see: Ring Gasket Handling and Inspection Before Assembly

Used BX-152 ring gasket with “coined” sealing surfaces.
This used ring gasket clearly shows the flattening of the corners, called “coining”. This “coining” occurs as a result of tightening the connection sealed by the gasket. Only by “coining” does the gasket close off any possible gap and create a seal.

Note: Coining yields or deforms the gasket so that any reuse will not reliably achieve a seal. ¹

Operators referencing this information, using a BX 152 gasket, should consider this example typical for all ring gaskets. ¹

Click here to see: Test Rack Tips

Information above, and in other parts of this Web Site, may help persons who really seek to know. If you have a question, and you think WOODCO USA may have the capacity to answer it, please use our Contact Us link and give us a chance to help.

WOODCO USA provides Web Site Tools for identification, estimating, and reference only. Do not use this information for manufacturing or inspection. Users of these tools should not use them as a substitute for professional engineering advice.  Anyone making use of the information presented does so at his own risk and assumes any and all liability resulting from such use.