HAZARD AND OPERABILITY ANALYSIS

Hazard and Operability Analysis (HAZOP) is a structured and systematic technique for package examination and risk management. It is used to identify potential hazards in a system or package as well as operability problems likely to lead to nonconforming operation.

HAZOP is based on a theory that assumes risk events are caused by deviations from design specifications or operating intentions. The identification of such deviations is facilitated by using sets of “guide words” as a systematic list of deviation perspectives. This approach is a unique feature of HAZOP methodology that helps stimulate the imagination of team members when exploring potential deviations.

HAZOP reviews are intended to reduce the probability and consequences of a major incident that would have a detrimental impact to operators, facilities, the public’s well-being, and the environment. The target of HAZOP is continued business operation and long-term profitably. The analysis looks for major incidents with potential for severe impact as opposed to minor issues of limited consequence. Such reviews should be updated and re-validated every six to ten years for machinery in operation, particularly if major changes have been made.

As a risk assessment tool, HAZOP contains brainstorming techniques and qualitative risk assessments. The success of a turbomachinery package review relies on the ability of rotating equipment engineer, operators, safety and risk advisors, and other subject matter experts. They predict deviations based on past experience and comprehensive knowledge of package operation. This should not re-place or duplicate design reviews. Rather, it is a formal safety and risk audit review to reduce or eliminate the possibility of major incidents.

Turbomachinery package HAZOP reviews are communication exercises. Information and data about turbomachinery packages are presented, discussed, analyzed, recorded and followed. Safety and risk aspects are identified to determine if adequate measures have been taken to prevent major accidents. Communication and qualitative evaluations are the primary facets of HAZOP procedures. A specialized HAZOP chairman should guide the review team. Sequential failures, operability features and operational control methods, for example, can be investigated for potentially varying conditions. Representatives from the client and operation teams should attend a HAZOP meeting, as well as engineers and experts from the contractor and vendor side. They should be supported by someone to record the information and facilitate the overall process. A well organized and properly manned HAZOP team should consist of at least seven people.

During a HAZOP meeting for turbo-machinery packages the HAZOP chairman and operation representatives raise any concerns or potential problems. Vendor representatives reply to questions and clarify such issues. Others observe and participate in discussions when needed. Ideally, a HAZOP chairman is from an independent HAZOP specialist company or consulting firm. He or she is senior to other review team members. The chairman and at least 30% of the review team are not directly involved in the facility or package design. This allows them to offer an independent assessment of the review process.

Typically, the constraints of manpower availability dictate that most of the HAZOP team is composed of those familiar with project design as well as vendor representatives. In any meeting, consultants should be included to ensure evaluation independence. Vendor representatives should be authorized by the vendor to negotiate and accept changes to turbomachinery packages. The role of risk engineers or safety representatives is also important. They provide risk evaluation, safety assurance, loss prevention, and environmental policies and practices to the HAZOP review meeting. They also confirm the underlying philosophy concerning risk acceptance and protection methodology. These experts should have reviewed cases of recent loss incidents applicable to similar turbomachinery packages. HAZOP reviews should be conducted in a timely, efficient and cost-effective manner. Meetings for all turbomachinery packages from the same vendor should be done in one session and completed within one week, if possible.