What is HAZOP?
Executive Summary
HAZOP is an acronym created by combining the words for HAZard and OPerability (Study). It is one of the most popular, non-quantitative Risk Assessment methods that is used to assess safety across a wide range of industrial operations, but not limited to, Oil & Gas, Refining, Chemicals, Petrochemicals, Glass, Pulp and Paper, Pharmaceuticals, Food and Beverage, Power Generation and any kind of industry where the processes may have presence of hazards.
This technique is even used in places like Mining, Steel Plants and Foundries. It is also used in Electrical Systems, called “Electrical HAZOP”. We will give a brief outline of this technique here.
History
This technique was first introduced many decades ago at the now defunct Imperial Chemical Industries (ICI) of the UK for risk management and to improve safety. ICI no longer exists today in that form. Various parts of the company were hived off, merged and/or have been taken over by companies such as Huntsman and AkzoNobel. However, engineers and safety professionals who worked in ICI and had information and knowledge about this technique, carried over this highly structured approach for identification of hazards and their mitigation, to these other companies and it quickly grew in popularity.
It was then also adopted for use in Electrical Networks, used to do risk assessment of the then newly emerging Computer Based Control Systems (DCS, PLC based systems) which was known as Computer / Control HAZOP or CHAZOP for short.
Within a few years, the method became mainstream and widely accepted, not only in the UK where it started, but all over the world, including in the newly industrializing countries such as India and China.
Now one considers it as the de-facto risk assessment technique used to improve safety in the process industry. It has even become a verb in some industries, when people ask “Have you HAZOPed it?” as soon as the process design stage of a new plant starts.
Before we dwell further, just remember that this is just one of many techniques (out of a bunch of risk assessment techniques) that engineers and other technical professionals use to determine potential accidents and their causes, to reduce risks in the workplace and improve safety.
Other techniques in the Process Safety domain include FMEA (Failure Modes and Effects Analysis), LOPA (Layer of Protection Analysis), HAZID (Hazard Identification), What-If analysis, Checklists, Quantitative Risk Analysis and Risk Matrix.
Also note that these days, Safety is an important consideration to not only protect assets, but also to prevent injuries to people and damage to the environment. Hence, Process Hazard Analysis (PHA) is required by law in many countries to be carried out in any facility that could have a high hazard potential, such as those having pressure vessels in their production areas. Although one can carry out PHA by many techniques, today this is the by far most popular technique, followed by What-If analysis (also known as SWIFT-structured what-if analysis).
OSHA Process Safety Management Standard (PSM standard), mentions this as one of the acceptable risk assessment techniques that can be used for PHA for compliance to this standard.
The Abhisam HAZOP training course is the only course, that covers everything related to Hazard and Operability Study including topics such as CHAZOP (Control System HAZOP).
Our HAZOP course is the only course on the market that covers everything related to Hazard and Operability Study including topics such as CHAZOP.
Our HAZOP Leader course is the only one which can be done fully online, has no limitations and earns you a lifelong title, certificate and an electronic badge.
In this situational video, the Project Manager explains to a young engineer how a HAZOP is carried out. Click the Play button to view.
This Guide continues below.
How to carry out a HAZOP Study?
The steps to carry out this are structured in such a way, as to identify the intentions and deviations of a particular operation, which we call a node.
But first, a HAZOP Leader (also called a Chairman) and a multi-disciplinary team should be formed to carry this out. The ability to get a great performance from the team requires the leader to have good managerial and leadership qualities, so that differences of opinion within the team can be resolved quickly.
The team members should also have knowledge, skills and capabilities (even if they are not really experts) to participate constructively in the study, which is similar to a brainstorming session. The efficiency of the study sessions thus depends on the effort made by both the leader and the participants.
Abhisam has separate courses for leaders and participants, so that competencies can be built.
The leader plans the study with a well defined scope of work and necessary input documents such as P & I drawings, equipment design data, plant layout drawings and standard operating procedures. Standards which are to be followed may also be decided (such as IEC 61882, which is covered in the Abhisam course or in- house standards).
The next stage of the procedure is to divide the plant or facilities into sections. Each section is called a node.
For example, a node may be a section of a plant that transports liquid products from a plant to a storage tank via inlet piping, valves, etc. Then in this node, the original design intent is identified, which is transporting liquids from the plant to the storage tank. Then all possible deviations are analyzed in detail. Deviations are formulated by combining guide-words with parameters. For example the combination of the word “High” and “Temperature” leads to a deviation of “High Temperature”. Similarly a combination of “Low” and “pressure” leads to “Low Pressure”.
Some of these deviations, may lead to a likelihood of an accident or unwanted event, such as loss of containment, or other cases where it results in other types of accidents.
Whether this could actually result in hazardous consequences, such as an accident or injuries to people, or damage to the environment, or other undesirable events, only the persons who are involved in the study can judge.
Note that this method is unique, in that not only hazard identification happens, but operability problems can also get highlighted, which results in a better plant. This method is hence used to not only assess risks but also carry out a review of operability issues.
Now, if this is deemed to be a hazardous consequence, then suitable mitigation is needed or better still should be prevented from happening at all. So one could suggest modifications to the piping (e.g. a reverse flow check valve). This is how the risk of something bad happening is assessed and also prevention & mitigation methods are listed in the study. Hence, the team then will recommend safeguards, preventive measures and controls.
The video alongside will also give you a brief idea of the technique.
In this situational video, the Project Manager explains to a young engineer how a HAZOP is carried out.
Documentation Software
One can use standard Excel templates to carry out the study, or use (either commercially available or in house developed) software that eases the documentation generation, such as automatically generating a pdf report.
However, note that software is not absolutely necessary to do this, it is only a tool that can make the process slightly faster and easier in some situations, because the software is used only for documenting the findings systematically. If used by a novice or an incompetent person, the best software in the world may well be useless! Hence, the quality of the team that carries out the work is more important than what software tools are used.
Also the people, including employees who are part of the study team should be well versed in the process, as otherwise, outsiders cannot judge whether a particular deviation could cause a bad outcome or not.
The team should be multidisciplinary because only then can various engineering solutions, of different types such as mechanical devices, electrical devices or process instruments be suggested.
Competency and HAZOP Certification
When it comes to doing any HAZOP Study, one of the most important questions to be asked is the competency of the persons who do it. Many times companies tend to outsource this to outside agencies. Such agencies can of course do the job, but only if well supported by the plant owner/operator because only they know the intricacies of their process. So outsourcers can be appointed as facilitators/ leaders or scribes or specialists, but the owner operator’s personnel also have to be part of the team for the study to be effective. It is not simply checking a few boxes here and there.
If an unskilled or untrained person carries out such a Study (using the best software or no software), the chances of doing a bad job increase manifold. Doing a bad HAZOP is worse than doing nothing at all because a bad one lulls people into believing that their study is complete (and the recommendations are implemented and the plant is safe and everybody lived happily ever after) when actually the opposite is true.
Hence, it is very important that only trained and qualified people should carry out these studies. For example, you could take the Abhisam Training course today to build your competency and that of your team as well. The course has an associated exam that can be taken online and a certificate of competency earned alongwith an electronic badge.
Our course is the only course on the market that covers everything related to Hazard and Operability Study including topics such as CHAZOP. You can view the demo on our Free Trial Courses page to check it out!
What about Operability?
Lastly thoughthis tool is well known as a risk assessment technique, it is also useful from an operability point of view. Thus it will identify potential operational problems too, such as the response time of a process operator to a process upset, whether manual valves have been installed in hard to access places and so on. However this should be part of the scope that is given to the team. Spending a little more time on analyzing operability issues in the plant, will be worthwhile as it can significantly affect the manpower deployment in the plant. Think of it as a kind of work study that could optimise manpower.
Cybersecurity Issues
Recently, this has become a factor in many risk assessment studies. In our view one can easily incorporate this in the standard templates while doing a CHAZOP. All the deviations that can happen due to faults in the DCS/SCADA/PLC/SIS could be either due to random hardware faults, systematic (software) faults or malicious attacks. The consequences for these will be similar and can be analysed. The mitigation, however, will need some expertise in designing fault tolerant systems. The Abhisam Industrial Cybersecurity training course will cover these aspects.
Free White Paper- What is CHAZOP?
Computer HAZOP or Control HAZOP refers to the Hazard and Operability Study technique being applied to Industrial Automation, Control Systems such as DCS, PLC, SCADA based systems.
Find out more in this free Abhisam Whitepaper or watch the video to know more.
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