Thank you JStephen,
I thought that even though the vessel itself is rated 5 psig, if there is a possibility to build up pressure in that vessel above 15 psig, then ASME kicks in.
In my case, I have a pump feeding the vessel (dead head: 120 psig), so I literraly can blow up the vessel in...
I have an blowoff tank rated 5 psig that has a vapor relief system on top (counterweight valve set at 3.5 psig) to release vapor to atmosphere. When we hydraulically overfill the tank (normal operation level is 50%), slurry is sprayed to the atmosphere through the vapor relief valve...
