2. Main causes of excess pressure

In an industrial unit, the causes and amplitudes of overpressure can be diverse and complex to analyze. When designing or modifying such units, it is important to take into account all circumstances that could reasonably constitute a hazard, and to ensure that devices are in place to ensure that permissible operating parameters are not exceeded, including pressure relief equipment. Standard NF EN ISO 23251 provides relevant analysis elements on this subject.

On LPG depots, the main causes generally identified are as follows:

• for storage tanks, abnormal heating due to heat flow (fire, etc.), the heat input of which increases pressure through vaporization of the liquid phase. This situation was taken into account by the decree of November 11, 1972 (using calculation formulas derived from API RP 520). Another situation...