Pressure Relieving Systems
Manage Risk and Reduce Costs
Equity Engineering is a leader in developing technologies that manage risk, and pressure relieving systems are a keystone in achieving process safety. Effective pressure relieving systems help clients meet their risk management targets, compliance requirements and business objectives.
Our engineers have been involved with the API’s Pressure Relief Subcommittee for over 15 years. Many are internationally recognized experts in the area of pressure relief system design and installation, and have contributed to establishing improved worldwide industry standards. Phil Henry, PE, an industry leader in pressure relief systems, has served as the task force chairman for the development of API RP 520, "Sizing, Selection, and Installation of Pressure-Relieving Devices in Refineries" for the past 10 years. Mr. Henry and other Equity engineers teach the official API Pressure Relieving Systems course, covering API RP 520, 521 and STD 2000.
Our pressure relieving engineers can assist clients with:
- Assessment of existing relief systems for adequate overpressure protection utilizing the current ASME, API and international standards. If deficiencies are found, we will recommend options to bring the system into compliance
- Analysis of relief valve performance concerns (e.g., chattering, nuisance lifting, and failure to lift) and recommendation of remediation methods to rectify the RV’s functionality
- Audits of pressure relieving systems to provide assurance that the methodology and engineering analysis used in the design is in compliance with ‘Recognized and Generally Accepted Good Engineering Practice’ or RAGAGEP
- Design of new relieving systems to provide adequate and economical overpressure protection (note that over-sized relief protection may also be a safety hazard)
- Risk-Based Inspection analysis for relief devices
These tasks require extensive knowledge of the mechanical design of the various pressure relieving devices, process piping fluid dynamics (liquid, vapor and 2-phase) and a working familiarity with the latest industrial pressure relief guidelines and standards. Our engineers have the required experience in these areas to provide proficient and reliable consulting regarding relief device applications. Additionally, we can perform analyses of the consequences of an overpressure event or release from a relief device.
In addition to these services, we can perform the following types of reviews:
- Assessments of a heat exchanger internal failure relating to the credibility of considering a full tube rupture as an overpressure scenario. We have the capability of performing tube vibration analyses and transient pressure surge analyses as part of a tube rupture scenario evaluation
- Application of paragraph UG-140 (formerly Code Case 2211) of ASME Section VIII, Division 1. This permits, under certain circumstances, the use of system design and/or instrumentation safeguards for overpressure protection in lieu of a pressure relief device
- Assessment of criteria and required conditions for the use of isolation valves in the pressure relief path
- Dispersion analysis of atmospheric discharges
- Flare system design reviews involving overpressure scenario assessments and possible simultaneous discharges of multiple relief devices; we can also assess the credibility of any flare load reduction credits (e.g. dynamic modeling, HIPS, favorable instrument response)
- Flare radiation and acoustic studies
- 2-phase relief system evaluation and sizing