Joint Efficiency for bolted blind flanges (ASME BPVC.VIII UG-34)

[p6g2p6]

I am designing a bolted blind flange on a very low pressure system (less than 20 psi) and I am using BPVC.VIII to determine the minimum thickness of the flange. I am using equation 1 because it will be a flat face flange with full face gasket, so there will be no edge moment. The formula is very simple, however I am not sure what value to use for the joint efficiency (E) because I cannot find values of E for bolted connections. It says to use table UW-12, but that only covers E values for welded connections. Does anyone know what E value I should use?
Thanks.

 

[cbPVme]

If the head is a single piece of plate, then set E=1. If it's multiple pieces of plate welded together, follow table UW-12.