HAZOP - Hazard & Operability

What does HAZOP mean in detail?

The PAAG (prediction of deviations, identification of causes, estimation of effects, countermeasures) or HAZOP (Hazard and Operability, IEC 61882) method is a systematic procedure for identifying sources of danger.

The process or system to be investigated is divided into functional units and the intended operation of each individual unit is examined for possible deviations with given questions. The study is carried out by an interdisciplinary group of experts whose participants come from different areas of the company. Thus, different perspectives and experience can be taken into account.

A safety assessment according to PAAG or HAZOP usually takes place in the following steps.

Forecast of deviations

In the first step it is necessary to foresee possible deviations from the intended operation of the process under consideration. For this purpose, the process is first broken down into individual steps (so-called target functions). A process can comprise a dozen to hundreds of target functions. Accordingly, the time required for the study must be planned and is therefore time-consuming in case of extensive processes.

If necessary, the detailed consideration can be limited to safety-related plant components. To forecast the deviations, each of these target functions is linked to so-called key words. The classical PAAG or HAZOP method uses the following seven key words (in practice, numerous modifications of these questions are used, which often substantiate the key words with different process parameters).

Estimation of the effects

The ENCOS experts team looks for (organizational and technical) causes on the basis of process knowledge and using their own experience, which could underlie the respective scenario. Countermeasures already in the system (e.g. operating instructions, overfill protections, bursting / rapture discs) are not initially taken into account.

Assessing the effects

The project team considers or calculates the possible effects that could result from each scenario on the basis of process knowledge. Here as well, existing countermeasures are not initially taken into account.

Countermeasures

Finally, the team of experts defines measures to prevent occurrence and, if necessary, to limit damage for the addressed safety-related scenarios on the basis of the findings and the technical feasibility. In this respect, reference and instructions may be made to existing facilities, provided that these are considered effective and sufficient under the damage progressions discussed. The required reliability (effectiveness) of the measures to be taken will depend on the severity of the effects and the probability of the causes taking effect.

In practice, the PAAG procedure is therefore often linked to risk assessment methods (e.g. ZHA, FMEA, LOPA, risk graph) and used as an instrument for hazard identification.

What we offer you:

• Initial consultation for more accurate coordination of the required services
• Definition of the project framework
• Organization of the HAZOP team incl. preparation
• Implementation incl. elaboration of possible hazards and risks by deviation from the plant-related target behavior
• Documentation and Evaluation

Benefits of a HAZOP

• Very effective method to detect weak points in the company or process
• Quickly identify security risks and take countermeasures
• Interdisciplinary cooperation - Success factor Team