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Overview of HIPPS System

Introduction to HIPPS

HIPPS is an abbreviation of “High Integrity Pressure Protection System”. HIPPS systems are applied to prevent over-pressurisation of a plant by shutting-off the source of the high pressure.

In traditional systems over-pressure is dealt with through relief systems. Relief systems have obvious disadvantages such as release of (flammable and toxic) process fluids in the environment and often a large footprint of the installation. With the increasing environmental awareness relief systems are no longer an acceptable solution.

HIPPS is applied to prevent over-pressurisation of a plant or pipeline by shutting off the source of the high pressure.

HIPPS provides a technically sound and economically attractive solution to protect equipment in cases where:

  • High-pressures and / or fl ow rates are processed
  • The environment is to be protected.
  • The economic viability of a development needs improvement
  • The risk profile of the plant must be reduced

HIPPS is an instrumented safety system that is designed and built in accordance with the IEC 61508 and IEC 61511 standards.

What is HIPPS?

The international standards IEC 61508 and 61511 refer to safety functions and Safety Instrumented Systems (SIS) when discussing a device to protect equipment, personnel and environment.

Older standards use terms like safety shut-down systems, emergency shut-down systems or last layers of defence. A system that closes the source of over-pressure within 2 seconds with at least the same reliability as a safety relief valve is usually called a HIPPS.

HIPPS System

A High Integrity Pressure Protection System is a complete functional loop consisting of:

  • The sensors, (or initiators) that detect the high pressure
  •  The logic solver, which processes the input from the sensors to an output to the final element
  • The final elements, that actually perform the corrective actions in the field by bringing the process to a safe state. The final element consists of a valve, actuator and possibly solenoids.
Traditional systems
In traditional systems over-pressure is dealt with through relief systems. Relief systems have obvious disadvantages such as release of (flammable and toxic) process fluids in the environment and often result in a large footprint of the installation. With increasing environmental awareness relief systems are no longer an acceptable solution. A relief system aims at removing any excess inflow, where as a HIPPS aims at stopping the inflow of excess fluids and thus avoiding over-pressure.High Integrity Pressure Protection System HIPPS
Advantages of HIPPS
HIPPS provides a technically sound and economically attractive solutions to protect equipment in cases where:
  • High pressures and / or flow rates are processed
  • The environment is to be protected
  • The economic viability of a development needs improvement
  • The risk profile of the plant must be reduced

 Overview of  HIPPS

 HIPPS is an instrumented safety system that is designed and built in accordance with the IEC 61508 and IEC 61511 standards. These international  standards refer to safety functions (SF) and Safety Instrumented Systems (SIS) when discussing a solution to protect equipment, personnel and environment.
A system that closes the source of over-pressure within 2 seconds, with at least the same reliability as a safety relief valve, is usually identified as a HIPPS.
A HIPPS is a complete functional loop consisting of:
  • The initiators that detect the high pressure. These initiators may be electronic or mechanical.
  • For electronic HIPPS, a logic solver, which processes the input from the initiators to an output to the final element.
  • The final elements, that actually perform the corrective action in the field by bringing the process to a safe state. The final element consists of a valve and actuator and possibly solenoids or mechanical initiators.

Two types of HIPPS

 Based on experience and expertise offers two types of HIPPS
1.     Integral mechanical HIPPS, since 1974
2.     Full electronic HIPPS, since 2000

1. Integral mechanical HIPPS – using mechanical initiators

In 1974 the German DVGW certified the final element including mechanical initiators in accordance with EN 14382 (former DIN 3381). Since that date has field experience with safety shut-off valves (with actuator and initiator) closing within 2 seconds.
Mechanical HIPPS safety loop
Main features of integral mechanical HIPPS:
  • Integrated safety loop to IEC 61508 / EN 12186
  • Safe and simple
  • Option not requiring external energy (stand-alone HIPPS)
  • No wiring required
  • Set point accuracy < 1%
  • System to SIL 3 or 4
  • Third party validated failure data
 Mechanical HIPPS System
2. Full electronic HIPPS – with electronic pressure transmitters
When designing a HIPPS always treats a HIPPS (and other SIS) as a complete certified functional loop and not on separate component level. Safety wise the HIPPS loop is designed in accordance with IEC 61508 and 61511. On the specification side of the final element the design is in accordance with EN 14382 (DIN 3381).
The misunderstanding that ‘system’ stands for controller and that a SIS can be designed on component level, is the cause of the biggest problem in the implementation of HIPPS. The under specification of mechanical components and the acceptance of component Safety Integrity Level (SIL) certification, instead of verification of the complete loop SIL is still a pitfall.
 Electronic HIPPS safety loop
Main features of full electronic HIPPS:
  • Integrated safety loop to IEC 61508 and 61511
  • No limit on distance between transmitters and final element
  • Communication with Plant Safety System
  • Possibility of integrated monitoring
  • Hard-wired solid-state logic solver
  • High integrity manifold block for safer operation
  • System to SIL 3 or 4

Electronic HIPPS System

HIPPS System: 1002 Electronic HIPPS system

1oo2-electronic-HIPPS

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