Flare Design for Air Failure

[ChemEngSquirrel]

I'm checking flare capacity for an offshore platform. Without going into any specific design dertial for my case (& given that offshore designs are often very similar in design):

Can anyone advise what i should consider as a flare scenario for inst air failure?

I don't think considering all 'air fail open' valves venting simulataneously is realistic as air systems generally decay in pressure over a perioid of time after failure, meaning valves will drift open rather than suddenly open simultaneously. However, i'm struggling to identify a realistic sizing case.

Thanks in advance for any input.