Moore Industries has published a technical white paper exploring the possibilities available to designers of Safety Instrumented Systems (SIS) using logic solvers as part of an overpressure protection system.
Available for download online, the ‘Logic Solvers for Overpressure Protection’ white paper provides examples of straightforward pressure protection system topologies and associated PFDavg (Average Probability of Failure upon Demand) calculations and Safety Integrity Level (SIL) classifications.
A high integrity pressure protection system (HIPPS) provides a barrier between high pressure and low pressure parts of an installation to prevent the release of fluid or gas into the environment. An example of an HIPPS is in an offshore well platform where the subsea oil or gas lines can occasionally present a harmful pressure surge in the pipeline. The HIPPS is designed to shut off the source before the design pressure of the downstream process is exceeded, avoiding a rupture of a line or vessel.
The ‘Logic Solvers for Overpressure Protection’ white paper shows safety engineers the steps needed to determine the right logic solver for their SIS. The white paper shows the methodology and calculations for determining the applicability of logic solvers in SIL 1 and SIL 2 environments. In many cases, discrete logic devices such as the STA Safety Trip Alarm are suitable for use while providing a flexible, low-cost and user-friendly solution.