5. Examples of mistakes to avoid when sizing valves

Non-exhaustive list:

• request a valve setting of 110% of the PS of the container or pipe. The valve must operate at maximum PS. Its flow calculation is carried out at 110% PS, corresponding to the initial transient phase of pressure relief;

• do not take into account the correct temperature data for hot gases, and the associated thermodynamic values;

• do not check the air flow rate (valve supplier data) corresponding to the hot LPG flow rate;

• forget the calculation of valves in a degraded operating situation (n – 1 valves) for maintenance or inspection;

• forget to take back pressure into account (or assess it incorrectly) in the case of valves collected in a capacity.