When evaluating the pressure relief requirements for a facility, it is important to examine all possible means by which a pressure relief requirement may arise. All applicable scenarios for a protected system should be evaluated and calculated. For many systems, one scenario will require the largest orifice area, while another has the highest associated inlet pressure drop, and a third scenario has the highest associated outlet pressure drop. The ability to automatically calculate multiple applicable scenarios is one of the primary advantages of iPRSM over spreadsheet based calculation tools.
The following are the standard scenarios that can be automatically loaded into a Protected System in iPRSM. For further information on overpressure scenarios, please consult the API 521 guidance document.
Users are not limited to the above scenarios and may define alternative scenarios for their facilities within iPRSM.
Want to learn more?
For further information, a demonstration or evaluation session and training classes, please contact us at:
T: +1.281.724.2222 | E: FES@curtisswright.com
iPRSM calculates the required orifice area and inlet and outlet pressure drops of a relief device. All of the calculations are performed per the latest codes and standards.
iPRSM also uses all of the latest and most accurate calculation methods to appropriately size relief devices. Among the current calculation methods for two phase flow are the DIERS Omega method and Direct Integration.
The traditional method of performing relief system calculations has involved complex spreadsheets combined with process simulators to obtain physical properties and thermodynamic data. A major deficiency with a spreadsheet approach is that it is difficult, if not impossible, to automatically evaluate the effects of process or equipment changes on multiple protected systems. This approach will likely provide you with an accurate snapshot of the process as calculated. However, with ongoing changes to your process and equipment, deficiencies in your relief systems are likely to slip by undetected. The most dangerous issue at your facility is the one you don’t know about.
Other PC based software packages are available. These packages lack the connected nature that iPRSM offers as a web based tool. In iPRSM, users collaborate in a single, common database as opposed to working from isolated computers. This approach ensures that all users always work with the most current data.
Other packages also require your entire team to have a common computing platform which becomes an issue when operating systems or other related software are upgraded. iPRSM simply needs a device with a web browser and can even be accessed via tablet or smart phone. With iPRSM the calculations take place on secured servers. The result is the bare minimum of computing power requirements.
As the equipment and process at a facility undergoes changes over time, it is important to verify that installed relief devices remain adequate for their protection role. iPRSM is built with protected systems as the building blocks. Protected systems are comprised of equipment that is protected, protecting, ancillary, or an overpressure source. It is common for equipment to be linked to more than one protected system and to play a different role to each system. For example, a pressure relief valve may be protecting a piece of equipment in one system, but also be ancillary to an upstream protected system. iPRSM is the only tool available that identifies the multiple roles played by a single piece of equipment. The result is that iPRSM will illuminate issues in your relief system that may have otherwise gone undetected.
If you need help auditing your relief system, Farris Engineering Services routinely audits our customers’ relief systems to ensure they will protect their assets.