ASME PCC-1 Appendix O has a lot of stress values to look up (or calculate) and using “defaults” isn’t going to help you solve real world problems. Over the next few weeks I’ll be going over where to get some of the stress values you will need in order to properly determine bolt torque values using ASME PCC-1 Appendix O.

Maximum Permissible Bolt Stress, Sbmax

Minimum Permissible Bolt Stress, Sbmin

Target Assembly Gasket Stress, SgT

Maximum Permissible Gasket Stress, Sgmax

Minimum Operating Gasket Stress, Sgmin-O

Minimum Seating Gasket Stress, Sgmin-S

Assembly Bolt Stress, Sbsel

Wait, just seven stress values? That seems way too easy! It is! But let’s start here and save the Maximum Permissible Bolt Stress for the Flange, Sfmax determination calculation using WRC 538 for after your exam.

Are your bolts designed to handle the uplift from moments caused by external forces like wind and seismic loads? 

I commonly see equipment where only the operating case is checked and I’ve even seen cases where the bolt uplift calculation is ignored altogether. Don’t be fooled into ignoring this simple calculation as catastrophic bolt failure can cause severe damage to your equipment.

The empty condition often governs because process weight helps to prevent uplift. Please calculate all design conditions to determine the governing case.

Can your saddle bolt holes handle the effects of thermal expansion in your equipment?

Bent saddles and sheared bolts from undersized slotted bolt holes pose a major operational risk that is often overlooked. It is much easier to design for thermal expansion before fabrication than it is to try to fix an inadequate slotted bolt hole length while in service. There is a simple calculation to determine if your slotted bolt hole length is enough to handle thermal expansion at design temperature. 

Please review PIP VEFV1100 for more information regarding the design of supports and other attachments.