Introduction to Hazard and Operability Review:
HAZOP is an analysis method that was developed for use with new processes JO the chemical Industry. Its strength is that it allows problems to be identified even before a body of experience has been developed for a given process/system. Although originally intended for use with new processes it need not be limited to new operations. HAZOP works equally well with old process/systems.
HAZOP consists of forming a team of experienced, knowledgeable people from a variety of backgrounds relating to the process/system. The team members brainstorm about potential hazards. The health and safety professional should chair the team and serve as a facilitator, The chairman role is to draw out and record the ideas of team members; make sure that one member does not dominate or intimidate other members; encourage maximum participation from all members; and assist members in combining ideas where appropriate to form better ideas.
A variety of approaches can used with HAZOP. The one recommended by the American Institute of Chemical Engineers (AICHE) probably the most widely used. AICHE recommends the following guide words; no, less, more, part of, as well as, reverse, and other than.
Hazard And Operability Review (HAZOP):
A HAZOP proceeds in a step-by-step manner. These steps summarized as follows:
- Select the process/system to analyzed.
- Form the team of experts.
- Explain the HAZOP process to all team members.
- Establish goals and time frames.
- Conduct brainstorming sessions.
- Summarize all input.
An example of a form that can used to help organize and focus brainstorming sessions. It can also used for summarizing the results of the brainstorming sessions. This particular example involves a plastic mixing process.
Only one component in the process (flow gate number 1) has analyzed. If the flow gate does not work as intended, there will no flow, too little flow, or too much flow. Each condition will result in a specific problem. Action necessary to correct each situation has recommended. Every critical point, sometimes referred to as a node, in the process would be analyzed in a similar manner.
HAZOPs have the same weaknesses as FMEAs: They predict problems associated with system/process failures. However, these are technological failures. HAZOP do not factor human error into the equation. Since human error is so often a factor in accidents, this is a weakness that must be dealt with. The next section sets forth guidelines for analyzing human error.
Human Error Analysis (HEA) Technique:
HEA, as described in the context of these chapters used to predict human error and not as an after-the-fact process. Although the records of past accidents can studied to identify trends that can, in turn, used to predict accidents. This should done as part of an accident investigation. HEA should used to identify hazards before they cause accidents. Two approaches to HEA can effective:
- observing employees at work and noting hazards (the task analysis approach); and
- actually performing job tasks to get a first-hand feel for hazards.
Regardless of how the HEA conducted, a good idea to perform it in conjunction with FMEAs and HAZOP. This will enhance the effectiveness of FMEAs, HAZOPs, and HEAs.