Risk Based Approach for Determining Fireproofing Requirements

There is only one known recommended practice, namely API RP 2218, that provides guidelines for selection and application of fireproofing in the petroleum and petrochemical processing plants. This recommended practice specifically addresses “pool fire” scenarios. The fireproofing need is determined based on equipment that handles flammable liquid above a specific threshold volume and the extent of the fire-scenario envelope around the fire potential equipment is suggested by API RP 2218. The same document also suggests performing a risk assessment in determining the potential needs of fireproofing. The risk based approach is particularly useful when dealing with LNG and liquefied gases used as refrigerants, because their accidental release seldom forms a liquid pool due to their very low boiling point and high evaporation rate. A recent study on pool fire modelling using an industry approved modelling tool proved that most of the liquid holding equipment in an LNG plant did not form liquid pools after an accidental release. Some other scenarios resulted in pool fires that did not last longer than few minutes and did not cause harm to structural steel members. These can withstand fires for several minutes based on their dimensions. This study shows how calculated pool fire size and duration will play a significant role in determining fireproofing requirements, and how a risk based fireproofing design together with the calculated time to failure of structural steel members may result in a significant reduction of fireproofing material quantities, and consequently a cost saving, which is desirable in the current economy.