Hazop (HAZard OPerability) is a systematic risk analysis methodology that is applied for well-defined processes, including design and existing facilities. It is possible to analyze a broad spectrum of hazards associated to process deviation. Additionally, it allows verifying process operability.
Key words are used in order to identify the process deviations. Usually, points are defined (also called nodes) into the system to be analyzed. In some cases it is very important to set up stream points of reference to better establish the process deviations.
The deviations are caused by equipment failures (random or systemic failures – special attention to common causes failures) or human errors. It should bear in mind that unintentional human errors are related to human factors, which should be reminded when setting up safeguards in promoting risk reduction.
The effects represent the outcomes of an accident since occurring the initiating event and all safeguards have failed. In this moment the entire risk analysis team has to be well aligned, because someone can quote that the event is impossible to occur due to the amount of safeguards. This is a correct assertion, however the moment to evaluate the safeguards effectiveness is during risk categorization.
Now, it is an instant to categorize the risk. It is known the risk is function of frequency and severity. If there are many strong safeguards to prevent an event and they are properly maintained, the frequency to occur the event will be very low. Regarding to the severity, it should be evaluated if the safeguards are effective to reduce the consequence of the scenario. The risk categorization will be completed when defining the frequency and severity of the scenario. Usually several companies have their own risk matrix in accordance with local laws or underwritten by them. If the risk is not in acceptable level, it is crucial to come up with recommendations to reduce the risk to a tolerable level, according to risk matrix.
To perform a well-done HAZOP it is important to have complete and updated drawings as well as updated information regarding process, products and equipment. Additionally, it must have a multidisciplinary team with experienced people in dissimilar areas in order to perform a risk analysis with quality assurance.
Hazop, for being a more complete risk analysis methodology, requests a longer time than other analyses to the completion. Nevertheless, the meet planning, availability of the process information and an experienced team will lessen the time of the work.
There are variations of Hazop that if well applied they will also help to enhance the safety pattern of the companies, such as:
- Human-HAZOP – evaluates in detail the human errors and human factors;
- Computer-HAZOP (CHAZOP) – analyzes the possible initiating events regarding basic process control system and safety instrumented system.
Hazop is an excellent risk analysis tool that will help your company significantly increase the safety standard. It will also attend the process operability conditions by providing insights to improve the process controls.