(32db) Applying ASME Section VIII Ug 140 (Code Case 2211-1) Reasoning to Exclude a Vessel from the Need for a Fire Case Relief Valve

This paper briefly discusses the history of Code Case 2211 and the resulting UG-140 update to ASME Pressure Vessel Code, Section VIII. This code case was the origin of ASME allowing SIS and other statistical arguments (such as FTA and now LOPA) to help a PHA team and a chief engineer from the involved process determine when there is a better alternative than a fire case relief valve. The first application in 1993 timeframe was a case where an external fire led to an explosive reaction of the contents of a reactor if the fire case PSVs vent during external fire and concentrate the higher boiling reactant.

The paper will discuss about 60+ cases analyzed at AR-RAZI in Jubail, KSA, where the vessels had no fire case relief valves. The step-by-step application of the Code Case 2211-1 approach is shown for each. Examples of the sign-off forms used by the PHA leader & chief engineer are provided to aid others. Of the 60+ vessels reviewed, 55 were exempted from the need for a fire case relief valve.