Valve Magazine - Spring 2008

MAINTENANCE & REPAIR

performance. Coupled with the pretest results, this is the only accurate way to predict frequency of inspections required to comply with plant PSM requirements.

CONs: There are two main downsides to a full inspection and overhaul; additional time and cost of repair. To properly overhaul any PSV, there are certain requirements that must be followed in order to provide a “VR’d” valve. This method can take 3-4 times longer (time may vary based on the size and condition of the valve) than that of a test only. Additionally, there are additional labor costs for the repair, as well as costs associated with transportation, plant labor (for removal and installation) and unit downtime. These factors need to be taken into consideration along with production schedules to maintain a true and accurate PSM program.

PSV Management Software

Determining the methods and frequencies of inspection is not an easy task. As stated, there are many factors—not just the “pop-point” of a PSV—that affect whether inspection frequencies should be shortened, extended or maintained.

Managing all of this information can be a daunting task. Having an internal database or using a repair/testing facility that is equipped with the proper database is essential to a successful PSV program. The ability to manage this information, help predict frequencies of repair, and assist in tracking history and total life cycle cost for each PSV is a critical component of the PSM process.

Summary

There are many methods of PSV inspection that are used to meet end-user PSM

requirements. Determining which method is the safest and most practical is not to be taken lightly. Although cost will always be a factor in the decision, safety, quality and efficiency considerations should play an equal (if not greater) role in determining PSM frequencies and methods.

A PSV is a plant’s last line of defense when it comes to protecting life and property. A properly maintained PSV will ensure that the end user, the community and the environment will not be exposed to equipment failure resulting in a catastrophic situation.