What Does
Control Systems HAZOP Mean?
A Control Systems Hazard and Operability Study (CHAZOP) is a hazard and operability study (HAZOP) of a control system, with the aim of identifying potential failures in the system.
The study is exclusive of the function of the underlying processes that they manipulate and maintain. It provides a systematic, structured technique that improves the safety and operability of electronic control systems.
Safeopedia Explains Control Systems HAZOP
Traditional HAZOPs evaluate potential points of failure in complex systems (facilities, processing plants, machinery, or components of a work environment). CHAZOP, on the other hand, is a procedure that carries out an analysis of the safety and reliability of an existing or planned computerized or electronic control system.
Objectives of CHAZOP
A CHAZOP provides a measure of the safety risks associated with a particular control system, giving a better sense of the control system’s effectiveness. All identified risks should then be controlled and minimized by incorporating suitable design and operational safeguards.
CHAZOPs typically focus on two broad facets of the control system:
- Whether the control loops (the set of instruments that operate the functions being controlled) are adequate for the process to which they are applied
- Whether the control system is properly integrated with the underlying process (to ensure that it does not cause unintended operational interference or obstruct the operation of another control system)
The Importance of Conducting CHAZOP Studies
A CHAZOP involves the study of a control system’s functions under all situations in which the controls could potentially be used, including:
- Startup of the machinery or process being controlled
- Normal operations
- Irregular operations
- Turndown
- Emergency shutdown
CHAZOP not only identifies hazards related to the integrity of the control system’s functions, but also the hazards related to the operability of the control system. Therefore, the effectiveness of a control system’s instrument layout, the material used to explain its functions to relevant personnel, and the notifications and alarms associated with it, are all evaluated as part of a CHAZOP assessment.
Testing procedures for control systems are also evaluated to ensure that they effectively monitor and verify the integrity of the control system. CHAZOP is a critical component of safety management in many industries where effective controls of systems are vital to occupational and environmental safety, such as the operation of offshore oil and gas platforms.
In most process industries, programmable electronic control systems have become the standard. These include Distributed Control Systems (DCS), Safety Instrumented Systems (SIS), Programmable Logic Controllers (PLCs), and Supervisory Control and Data Acquisition (SCADA). Incorrect operations of these systems can subject personnel and a facility to severe risk. CHAZOP can be used at any stage of the evolution of the control system.