To complete purging, what is the total number of purgings required after increasing pressure by 15 psi?

The total number of purgings required after increasing pressure by 15 psi is determined by understanding the purging process and how pressure changes affect it. In scenarios based on established industry practices, every increment in pressure often necessitates a specific number of purges to ensure the system is free from contaminants and that the desired pressure is safely maintained without carrying over any residue.

In this case, the process typically follows a protocol where a predetermined number of purges corresponds to increases in pressure increments. Given that 15 psi is a significant change, it may correspond to established guidelines that suggest completing five purges to properly clear the system and confirm that everything is functioning correctly and safely.

Therefore, the rationale behind needing five purges after a 15 psi increase aligns with standard operating procedures in many technical fields, where safety and effective operation of systems are paramount. This is why the answer aligns with the total of five purgings after such an increase.