ASME VIII-1 UG 44 rules for non metallic gaskets

[Sachin Pawar]

Hello All,

It seems UG 44 rules from ASME VIII-1 are based on metallic gaskets as UG-44 (a) gives reference of ASME B 16.20 only and not ASME B 16.21. Alsi UG-44 (b) states that The assembly bolt load must comply with ASME PCC-1, Appendix O; This method was developed using a spiral wound gasket. How to apply UG-44 rules for a non metallic gasket with some modification in formulae or may be by reduction in Fm factor? Or is there any other method to be applied?

Please share your thoughts.

Thanks,
Sachin

 

[Cobra17]

Standard Designation: BPV Section VIII Div 1
Edition/Addenda:
Para./Fig./Table No:
Subject Description: Section VIII, Division 1 (1989 Edition, 1991 Addenda); UG-44
Date Issued: 04/07/1992
Record Number: BC92-077
Interpretation Number : VIII-1-92-60
Question(s) and Reply(ies):
Question: Is it permissible to use ANSI B16.5 flanges in accordance with UG-44 of Section VIII, Division 1, when used with spiral wound gaskets or any other gasket without any calculation per Appendix 2?

Reply: Yes.

 

[Sachin Pawar]

Hello Cobra17,

The interpretation holds good for only pressure and temperature loading. Whereas I am curious about external piping loads on nozzle where the Fm factor comes into picture which I believe is dependent on gasket MOC.

Thanks,
Sachin

 

[Cobra17]

Looks like Compress just does it according to App O. I used a B16.21 nonmetalic flat gasket, Elastomer with mineral fiber fabric 2-ply


ASME PCC-1 Appendix O Simple Approach
Sbsel = SgT*Ag / (nb*Ab) (O-1)
Tb = Sbsel*K*Ab*fb (O-2)

Results
Ag = pi / 4*(9.88^2(gasket OD) - 6.62^2(gasket ID)) = 42.25 in2
Sbsel = 30,000*42.25 / (12*0.302) = 349,723 psi
Tb = 349,723*0.172*0.302*0.75 / 12 = 1,135.4 lbf-ft

 

[TGS4]

The research that was done to develop the rules in UG-44(b) (PVP2013-97814) assumed spiral wound gaskets. There is no research supporting any values for other gasket types.

In the case of Section VIII Division 1, this then reverts to a U-2(g) issue.