HAZARD OPERABILITY STUDIES (HAZOP)

HAZARD OPERABILITY STUDIES (HAZOP)

Oleh : Bayu Nurwinanto

Motivation

The hazard and operability study (HAZOP) is a creative technique for identifying hazards and operating problems in a process plant. Increasing demand by governments and public bodies for improved safety in addition to a strong awareness within the industry that safe operation can also be highly efficient and profitable, support the need for plant safety and effective safety management. Advances in technology and trends to highly complex and integrated plant designs have sensitised people for systematic and sustainable methods to identify hazards of which the HAZOP study is generally recognised as the foremost solution being able to cover standard and also new complex technology. The operator of a technical installation by which health and safety, the environment, assets and the operator’s reputation could be affected is obliged e.g. by European legislation to:

1. have an up-to-date knowledge about all safety relevant aspects of their operations,
2. prevent accidents or to limit their impacts/escalations (acc. to seveso II Directive)
3. control hazards reliablity and to minimise risks by identifying intallation with risk potential regarding health and safety as well as the environment, evaluating their inherent risks and specfying risk mitigation measures (which is part of the risk management process)
4. design, start up, operation and maintain workplaces in such a manner that workforce can conduct work without putting their own safety and health or that of others at risk (§2 Abs.l Allg. Bundesbergverordnung ABBergV, §3ArbSchG)

Objectives

The primary objective of a HAZOP study is to identify potential hazards and operating problems on e.g. a process plant. Performed by a multi-disciplinary team which applies the HAZOP structured brainstorming technique all possible deviations from normal operating conditions are examined in detail and their reasons and consequences are assessed. The detailed insight into the plant is supported by dividing the plant into manageable sections, so called 'nodes'. Specific 'parameters' and 'guidewords' are used to focus the team towards likely design issues in each section of the plant. Once identified, potential 'deviations' from the standard operating or design conditions may then be discussed and assessed by the team with respect to their effect on safety. Subsequently the implemented safeguards are identified and where considered necessary recommendations for action or further consideration are recorded and presented in the form of the HAZOP Report. The necessity of additional safeguards/recommendations can either be evaluated by the team on a qualitative basis or by means of a risk matrix. HAZOP studies may be held at any time during the design and operation of a plant. Most effectively they are conducted during the conceptual design phase where recommendations affecting the general design may be made. The analysis serves the operator as a proof to operate his installations such that hazards for employees, third parties, the environment and the surroundings can largely be excluded. The operator’s management gets an up-to-date picture of the present hazards, their possible effects and ways to solve these issues.

Frequency Of Reviews

HAZOP analyses are usually to be revised when considerable modifications, upgrades or re-design of existing facilities are carried out or if events like accidents, critical situations or near misses call for this. In this context a change, upgrade or re-design is to be considered as essential if process modifications associated with consequences for safety or safety related equipment is involved. This also applies for utilities including buildings, machinery, equipment et al. that do not necessarily contribute to the operating objective directly but that are associated with the process facilities in terms of layout or operationalwise and that are safety relevant. Those being in charge of operations and those working in the facilities are obliged to indicate all identified possible changes. In principle operators are expected to repeat the analyses at least every 5 years in order to maintain the residual risk as low as reasonable practical.

Offered Service

The success of the HAZOP technique strongly depends on the skills and experience of the facilitator in preparing and running the study. A sufficient depth to derive all the potential hazards and safety related operability problems and on the other hand the avoidance of a time consuming design review which is out of scope for a HAZOP are essential for the effectiveness and quality of the sessions. The service offered in this matter is the provision of an experienced facilitator /chairman that leads through the HAZOP sessions supported by an experienced minute taker/scribe who notes down the relevant results into the prepared HAZOP spreadsheet. Depending on clients’ needs in house spreadsheets or a special HAZOP software tool will be used by the HAZOP management team. Subsequently upon completion of the sessions a report will be prepared by the HAZOP chairman and submitted to the client.