Valve+Actuator Blast resistant design; API RP 2A

[NGiLuzzu]

In a project specification (by ConocoPhillips - Aker Kvaerner) for valves to be installed on a platform in the Northern Sea, it is possible to read: "... The equipment shall be designed to withstand a blast load of minimum 0.3 bar drag..."
What does it mean?
From a website about naval weapons [1], I can argue that the blast load can be found as the product of the drag pressure and the area of the surface perpendicular to the shockwave front... but, once you have calculated it, how can you apply it to the design of a valve and actuator assembly?
In another related website [2], the following API reccommended practices are mentioned:
API RP 2A;
API RP 75;
API RP 14G;
API RP 14J.
Does anybody know if they can help?

Many thanks to all, 'NGL


[1] =

http://fas.org/man/dod-101/navy/docs/es310/dam_crit/dam_crit.htm

[2] =

http://www.mslengineering.com/msl_files/Profile-BP2.htm

 

[JWB46]

Basically what you need to do is as follows:
-set up a piping stress model of the system including your valve and actuator.
- calculate the natural frequency of the system
- the spec should give the blast impulse shape (typically a 0.2 - 0.3 sec triangular pulse) if not this would be a good assumption for practical design
-work out the dynamic amplification factor (daf) from your natural frequency and pulse shape eg graphs in Biggs Structureal Dynamics but also in lots of other dynamics books( daf may possibly be lower than unity but would more usually be about 1.5)
- the design load is then 0.3 bar x area of your valve etc x daf
- design for thse loads.
Assumption in all the above is that your system remains elastic.
Hope this helps. Come back if you need something clarified.
Best of luck.