I am working on the alternative release scenario portion of my risk management plan (RMP), as required by 40 CFR §68.28. Specifically, I am trying to calculate my release rate and release quantity values. The final rule does not specify exactly how to calculate these values for the alternative release scenario, as it does for the worst case release scenario. The Offsite Consequence Analysis Guidance describes fluid flow calculation methods and other referenceable methodologies. Would these calculation methods be acceptable for determining my alternative release scenario release rate and release quantities?

Yes, sources can use the OCA guidance methodology or any other technically sound method to calculate Alternative Release Scenarios.