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ASME B16.5 table 8 or 9??

ASME B16.5 table 8 or 9??

ASME B16.5 table 8 or 9??

Good day All,

In regards flange thickness (tf as per ASME B16.5), I always refer to Table 8 for class 150#. But without clear explanation, now one of the new vendor had delivered us as per table 9, picture below.
Gate valve 1/2" Class 150#, material is WCB, measured upon arrival tf is 8,6 mm. Whereas table 8 should have minimum of 9.6 mm. And manufacturer without any technical justification refer to table 9 with minimum 8 mm.

I do read the notes on (1),(2) and (4) on both table. It is bit grey area the definition of integrated flange (read: fitting).
Did some simple calculation using flange stress analysis. Gasket used is spiral wound gasket
with minimum 9.6 mm, it would requires 64 Nm to tighten the 4 bolts. Maximum 97 Nm prior jeopardizing the flange ring structure.

With 8.6 mm, it would requires maximum 44 Nm to tighten the bolts, before the integrity of the flange's 'ring' is start to be compromised. This torque value quite on the low side and not as per our flange management standard. I've seen bent spiral wound outer ring upon tightening, but never really see bent flange ring.

I will reject the valve, but aside from above stress calculation, does it really justified with respect to ASME B16.5 for them to use table 9? So far this is the only counter argument from the manufacturer.
Kindly advise,

Thank you in advance,

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected


RE: ASME B16.5 table 8 or 9??

Well I think your only defence / point is are they cast integral with the valve or welded afterwards?

If cast integral to the valve then I think table 9 will apply. Note 1 to me is quite clear - it needs to be cast as a single piece to get the benefit of the thinner flange

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: ASME B16.5 table 8 or 9??

Use table 9. table 8 is incorrect table.

valves are considered fittings, when referring to ASME B16.5 so they refer to the fitting table. Please refer to Table 9 note (1) where it talks about how loose flange is slightly heavier. as the integral design gives the flange strength, so not as thick of a flange is needed for integral flange valves. Do notice that it's only for the very small sizes.

Some can argue, If a welded flange is welded unto a buttweld joint end valve to use the thicker flange. But for integral flange design, use the thinner flange thickness as minimum. However, this is more rare for class 150 valve.

Some history. look at forward section, you will see that all references to valve was removed. so you must now think of things either as a "stand alone flange" or "integral flange on a fitting"

Luke | Valve Hax | https://valvehax.com/

RE: ASME B16.5 table 8 or 9??

ASME B16.34-2017, Valves - Flanged, Threaded, and Welding End, paragraph 6.2.2 states in part, that flanged ends shall be prepared in accordance with ASME B16.5 or ASME B16.47.

Thickness is to be per flanged fittings for Class 150 and 300 valves.
Thickness to be per flanges for Class 600 and higher.

So Table 9 thickness only applies to Class 150 and 300 valves.

RE: ASME B16.5 table 8 or 9??

Thank you all for the explanation.
It is quite interesting that:
- ASME still put smaller sizes on both table 8 (loose flanges) and table 9 (flange fittings), so we have to 'assume' that
- All smaller sizes 150 and 300 valves are cast integral/flange fittings.
- And also that most of its counter piping flanges are as per table 8.

Thanks again,

All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected


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