The general steps in a pressure relief system analysis are the same, whether the analysis is of a new facility for the purpose of designing a pressure relief system, or of an existing facility for the purpose of validating and documenting an existing pressure relief system. This process can be broken down into the following five steps:
1. Identification of all potential causes of overpressure for every piece of equipment within the scope of the analysis. This requires that each piece of equipment be checked for potential causes of overpressure. The applicable causes are typically classified at this point in the analysis according to whether they apply only to the equipment item under consideration, or potentially to other items as well.
2. Calculation of the required relief flow rates associated with each of these potential causes of overpressure.
3. Evaluation of existing (or design of new) relief devices to ensure that a relief device exists to provide each required flow rate determined in step 2.
4. Evaluation of existing (or design of new) inlet and outlet piping of each device to ensure that it can provide the actual (“rated”) flow capacity of the relief device without interfering with the device’s performance.
5. Evaluation (or design) of discharge collection and disposal systems to ensure they are capable of handling all of the potential required relief flow rates that are discharging simultaneously (“simultaneous release”).