Minimum bonnet thickness

Depends on;- which valve type/design/manufacturer/code and/or standard requirement.

ASME B16.34 could be your answer.


*** Per ISO-4126, the generic term
'Safety Valve' is used regardless of application or design ***

*** 'Pressure-relief Valve' is the equivalent ASME/API term ***

Thank you very much


We can calculate the The minimum wall thickness according to ASME B16.34 with Table VI-1 Basis Equations for Minimum Wall Thickness and Table 3 Valve Body Minimum Wall Thickness.

But ASME B16.34 is saying nothing about the bonnet thickness. Please see attachment.


Thanks in advance for your time.

I am having problems understanding how your attachment represents a 'bonnet'. Can you provide more detail such as what valve design are we discussing here.


*** Per ISO-4126, the generic term
'Safety Valve' is used regardless of application or design ***

*** 'Pressure-relief Valve' is the equivalent ASME/API term ***

ASME B16.34 does not provide information on how to calculate the thickness of the bonnet flange. It only provides instructions regarding the required area of the bonnet bolting.

The valve designer must choose the method to determine the bonnet flange thickness. It could be any of the following:

1. Calculation using the flange formulas in the ASME Boiler and Pressure Vessel Code. Be careful to use the right formula.
2. Calculation using Roark's formulas for stress and strain.
3. Calculation using another method such as finite element analysis.
3. Pressure testing.
4. Any combination of these.