The High Integrity Pressure Protection Systems (HIPPS) is a mechanical and electrical system designed in order to reduce the chance that the system pressure will exceed the tolerable allowable pressure. The protection against over-pressure is obtained by quickly isolating the source causing the overpressure.
The entire HIPPS package consists of:
- Logic solver
- Final Element
The initiators are field sensors and they are the inputs required to detect the hazardous condition. The logic solver accepts these inputs and generates correct outputs that change the state of the final elements in order to mitigate the hazardous condition.
WHY AND WHEN USE A HIPPS
These systems are used in the oil & gas industries in order to provide pressure protection of pipelines, piping, vessels and process packages against over pressure, allowing the use of lower design pressure downstream the HIPPS.
Conventional design standards against overpressure are based on the use and the proper sizing of relief devices, such as relief valves.
With HIPPS the overpressure protection is achieved by reducing to a tolerable degree the risk that the pressure can exceed certain maximum levels. HIPPS design is governed by:
- IEC 61508: "Functional Safety of Electrical / Electronic / Programmable Electronic Safety Related Systems"
- IEC 61511: "Functional Safety: Safety Instrumented Systems for the Process Sector,"
- ANSI/ISA S84.01-1996, "Application of Safety Instrumented Systems (SIS) for the Process Industry,"
The use of the HIPPS becomes the only feasible and practicable approach from a technical and commercial point of view, especially when:
- environmental restrictions and safety constraints limit the venting
- overpressure risk shall be reduced
- extremely high pressure and/or flow rate are involved
- sizing of relief device is difficult to define or inadequate due to chemical reactions, multiphase fluids or plugging
- on existing systems in order to avoid replacement of flare system when adding new units