Maintaining the integrity of the relief system design basis for a PSM covered facility is no easy task. Especially when a single facility, such as a refinery or chemical plant, can contain thousands of relief devices. However, as the old saying goes, “there’s more than one way to skin a cat”. Our clients have chosen everything from complex software to simple Excel templates, and there’s certainly no right approach. At the end of the day, choosing a methodology to manage the integrity of your facility’s relief system design basis comes down to what works best for your facility while remaining PSM compliant. Several factors to consider are:
- Cost: First and foremost, maintaining a relief system design basis isn’t cheap. Software licenses can cost thousands of dollars per year, but the number of man hours required to update individual Excel spreadsheets and PDFs can certainly make even small updates time consuming and cumbersome. Software may make sense if your facility has thousands of relief devices or if the intent is to use the program across multiple facilities. But if your facility has relief valves on the order of dozens instead of thousands, a cost benefit analysis may show that software does not make financial sense. Another factor to consider is data migration. The efficiencies gained by using software often do not materialize until the existing data has been migrated into the software, which is usually a substantial upfront cost. Ultimately, the decision comes down to what your facility can afford and what infrastructure (personnel or IT) needs to be put in place to make implementation successful.
- Accessibility: Another factor to consider is the accessibility of the documentation to personnel. Will everyone at the facility need access to the relief device folders? What about corporate employees? Storing RV folders on a shared network makes it easy for anyone who needs the folders to have access. This is useful, for example, if a PSV lifts, and the operator, engineer, or supervisor, wants to be able to check that the specific scenario is covered in the folder. Software often has limited licenses and usually, only specific people who have access to the software can access the folders. The type of license would also be a factor to consider. Network, web, individual PC, and USB licenses all have their pros and cons.
- Ease of Use: How easy is it for the average engineer, who may not be familiar with relief systems, to use? Software has a few advantages here, as Excel templates are not always intuitive, and you often must understand the calculations well to know whether your results are valid. Some software also has the advantage of a built in thermodynamic engine and usually has some degree of automation that makes quick work of calculations that require iteration. Excel can sometimes require manual iteration to converge on an answer, which again, may not be intuitive to someone who is not familiar with the workflow process of sizing relief valves. However, the costs associated with vendor trainings to teach personnel to use the software are not insignificant and may outweigh the gained efficiency. In addition, an advantage of Excel templates is that software often comes as a “black box”, such that you don’t know exactly what calculation is running behind the scenes or what inputs are coming from where. In Excel, however, you know exactly what formula is being used and have control over all the inputs to the equations.
Not enough can be said about developing good documentation for the sake of posterity, continuity, and facility operability. There are many factors that go into deciding how to manage the integrity of a facility’s relief systems documentation. The right approach is the one that helps your facility stay PSM compliant in the most convenient and cost-effective way. Reach out to Cognascents today with any questions about managing your facility’s relief system design basis. We are here to help.
