Could anyone help me with how to perform blast analysis in Caesar II?
We have made some stress calculations for the piping systems on an FPSO. Now we are asked to consider blast loads in our calculations. Is this relevant? What would be the stres allowables?

Thank you in advance for your support.

First thing to read is DNV RP D101 available on the internet. Then there are some posts on this forum (use search function - "blast") This will answer to your questions.

And yes, is relevant.

If you still have questions I will be glad to answer.

Regards,

You will save time and grief if you spend some time with your client and agree exactly what they want from a blast analysis.

Do they really want a blast-proof plant design ? Or maybe containment of inventory ? Both can be very expensive and beg questions like ... what about level bridles on vessels ? How do you protect those large projected areas with small, weak vessel connections ?

What about 'missile' impact with piping / vessels ? A missile in this case may be a piece of schrapnel or a wrench for example, propelled by a blast.

It may be that your client just wants major access ways to remain clear after a blast, and maybe the survival of primary steelwork. This would be a lower cost option.

Just a few pointers.

My opinion is that is not a useless effort. Yes, it is only a part of the global management of fire and blast hazard. And even if it save one life is priceless. Blast calculations become a requirement after Piper-Alpha explosion and HSE and UKOOA paid millions for research. Today is a standard requirement for topside modules and the client can not obtain classification without these calculations.

Regards,

Thank you all. The point is that the vessel is designed and is in place and has already started the production. Now our client has asked us to explain why we have not considered blast calculations in our design. I have not been involved in the early stage design but the argue was that the blast loads are negligible compare to the other loads. Now we are asked to justify this assumption and I need to perform the analysis for a couple of systems and check whether this assumption is correct. However, I have never made blast calculations using CAESAR II.
Anyways, thank you both.
Cheers,