Permissible Imperfections in Flange Facing Finish for Raised Face and Large Male and Female Flanges 1

[AWeld1]

B16.5 - 2003 Table 3 Permissible Imperfections in Flange Facing Finish for Raised Face and Large Male and Female Flanges

Greetings!

I would like to ask on how to evaluate the flange face imperfection referring to B16.5 - 2003 Table 3 p.61

Please see the attached document and please let me know if the flange is still accepted or not.
The material is 1/2 Inch, PN10 RF Type A182 F316L

Thank you very much.

Kind Regards,

AweldI

 

[XL83NL]

B16.5 is for Class designated flanges, not for PN10. PN designated is in the scope of the EN 1092-series.
Second, keep in mind B16.5 acceptance criteria are for new flanges.

I suggest to get a copy of PVP2013-97813. The current acceptance criteria in B16.5 for flange imperfections are, at some parts, unrealistic.
The paper by W. Brown elaborates on how to overcome this problem. He also gives recommendations of what is considered a better acceptance criteria.
Here's what he has to say on this table;

The issue with this requirement (table 3) is that it allows a flaw across the full surface finish to half the serration depth. It also allows a flaw to full serration depth across anywhere from 0.12 to 0.5 inches in the radial direction, depending on flange size. It also allows a defect in the flange surface finish of between 0.06 and 0.25 inches deep, with the same radial width. The latter two limits correspond, respectively, to defects that are the serration depth and approximately one half of the gasket width for a spiral wound gasket and significantly deeper than the serrations and one quarter of the gasket width for a spiral wound.

That being said, applying PCC-1 2013 to find out how radial is to be interpreted, I think your 1st measurement is incorrect, the 2nd is correct (that one is actually the radial distance).
For radial imperfections, you have to measure along the path from center to the raised face end, radially.
That what u did in picture 2. In picture 1, you measured some sort of width in stead of depth.

Think of a leakage path, and the potential a flaw has for leakage to be initiated.
The deeper (hence less chance the gasket filler may fill the flaw) and longer (i.e. more radial) the path, the greater the potential for leakage.

 

[AWeld1]

Thank you for the confirmation on how to measure the radial projection.

With regards to ASME B16.5, the imperfection shown in the picture would actually fall on the radial projection (3mm) only and not on the redial projection and depth category (1.5mm), is that correct?