HAZOP Guidewords

HAZOP Guide words are one of the unique things about the Hazard and Operability technique. There are a set of commonly used words that can be used to generate multiple abnormal scenarios, which we call as "deviations" in the technique. Every such word coupled with a particular parameter, then represents a unique deviation. For example to study a deviation of a flow lesser than normal, we use the guideword less or lesser than, coupled with a parameter flow. These two combined give us the deviated scenario of less than normal flow.

This less than normal flow is then analyzed thoroghly by the HAZOP team members to brainstorm if it will lead to nay dangerous consequences. If such is indeed the case, then the team's scribe (also known as HAZOP Scribe) writes down this as a dangerous consequence in the worksheet. Generally if the plant's design is sufficiently robust, then such deviated conditions are taken care of by the basic process design such as for example, having a flow switch that trips the pumping if the flow is low (just an example). If not, then the team suggests this, which goes into the worksheet as a recommendation. There may be of course other ways in which these parameters can be recognized and safeguards built, to correct for the effects of such abnormal conditions happening.

But then we are deviating from the topic- we are here to learn about guide words, right? You may be wondering how can somebody think of all the guidewords that are needed? Well, you can simply write down all of them at the beginning itself, or enter them into your HAZOP Worksheet before you begin the study. If you are using a documenting HAZOP Software, then the guidewords are already in the database and will be used to generate the different scenario conditions.

What are some common examples of such guide words? Here is a snippet of such a list below:
LESS
MORE
OTHER THAN
REVERSE
NO
EARLY
LATE

Now if you couple them with a parameter such as FLOW, you get the deviations as below:
LESS FLOW
MORE FLOW
OTHER THAN FLOW (checks if the fluid has been substituted by another one)
REVERSE FLOW (direction of flow has changed)
NO FLOW (empty)

The below ones can be used for batch processes, where sequencing is of importance.
EARLY FLOW (fluid starts flowing earlier than what is designed)
LATE FLOW (starts flowing later than designed).

If you need a more comprehensive training in this technique, then simply go to the HAZOP training course here. You can get access to an excellent e-learning course and what's more, also earn a certificate and an electronic badge, if you pass the associated exam.

Is HAZOP mandated by law? Where can I learn about it?

Hazard and Operability Study (HAZOP for short) is a highly popular Risk Assessment method that is the de-facto primary way of studying the amount of risk in any process industry operation. By process industry we mean Oil & Gas, Power Generation, Mining and similar sectors. In this method, we break down the process units into smaller sections called nodes and every such node is studied in depth with respect to what can go wrong and if it does then what? These are known as deviations.
The short video below gives an idea of the process.

All this is known, but the question that is asked by many is whether there is any legal basis for carrying HAZOP? Well, the answer is Yes and No. If you are looking for some Bill passed in Congress or some Act of Parliament in some country that says you must do a HAZOP, then no. There is to the best of my knowledge, no such law. BUT many of the legal acts in various countries and other rules and regulations have some references. For example in the US, following OSHA guidelines is mandatory by law and their 14 elements of Process Safety Management (PSM) do include Risk Assessment of the process, where HAZOP is specifically mentioned.

So while there is no direct law that says that you must do it, there are many indirect legal references that say that you must do it. Finally, all that matters is that if ever there is an accident AND the matter goes to court, the judge will be mighty annoyed if he/she discovers that you were not carrying out Risk Assessments such as HAZOP, especially when everyone else is doing it and it is given in OSHA guidelines and the fact that it costs much much less, than the cost of the plant (or the cost of the accident, which will be anyway more than the cost of the plant).

So now take your pick , whether to do it or not.

HAZOP Training Video

Here's an excellent video to everybody who wants to learn about Hazard and Operability Study (HAZOP) technique, in one easy video that takes baout 5 minutes to watch.

The video is in a very interesting format. It tells the concept in the form of a story of a greenfield chemicals manufacturing project. A young project engineer, wishes to know more about why they need to do a hazop study for it. Her boss, who is the project manager, explains in a very easy way of why and how it is done.
Do watch it to get new insight on the topic. As usual if you need more information on this then the best thing to to visit the HAZOP Training page and get trained and certified!

HAZOP training

April 14, 2014- For those of you who wish to know and understand more about HAZOP (Hazard and Operability Study) and associated stuff, there are basically three ways to do it. Here is a list  of them with their associated advantages and disadvantages:
a) Surf the web- just like you likely found this page while searching for terms like HAZOP or HAZOP Study free pdf.There will be hundreds or even thousands of articles that range from the fairly easy to understand to the completely complex ones which may leave you gasping for breath (or bored enough to go to sleep). Also the variety and scope will be mind boggling. You will learn all the jargon though...to impress your friends who have no idea about HAZOP studies.
b) Read a book. There are a few about Risk Assessment and HAZOP. None of them covers everything though, so you will have to buy at least three of them to learn anything of value. Of course even if you read them and understand the concepts, you will have nothing in your hand that proves to the world that you know your stuff!
c) Download the HAZOP e-learning course from Abhisam, that covers everything about HAZOP  in one, short, easy to understand course. There are several animations and simulations that explain key concepts and make this difficult to understand subject very easy to learn. Besides you can take their online exam and get a Certificate of Competency too, on passing!

HAZOP Video-Training Course

Here's a great video about HAZOP training that is on Youtube. See it below for yourself. The video basically tells you about HAZOP and how you can learn it in the comfort of your own home or office. Attending classroom trainings can be a pain these days, as you will have to spare time as well as a great deal of money AND be away from work to attend it. At the end of the day you may forget everything!

So here's an alternate way to learn all about the HAZOP process and also get certified in HAZOP! Note that it is not just a HAZOP ppt, it is a complete course.

HAZOP Study

HAZOP Study- What is HAZOP?
(Note: To learn about HAZOP Study in detail and to get certified as a competent person, please download or enroll online in the Abhisam HAZOP training course)



HAZOP is an acronym which is short for Hazard and Operability study and it was first introduced many years ago by ICI, a multinational chemicals company, based out of the UK. ICI no longer exists today as ICI (various parts have been taken over by companies such as Huntsman and AkzoNobel), but the HAZOP study technique that they pioneered, continues to grow in importance.
HAZOP is a risk assessment technique, used mainly in the chemical  and process industries such as oil and gas, refining, petrochemical, heavy chemicals, pharmaceutical and power generation as well as industries such as mining too. HAZOP is one technique out of a group of risk assessment techniques that form part of PHA (Process Hazard Analysis) . Other techniques in PHA are FMEA (Failure Modes and Effects Analysis), LOPA (Layer of Protection Analysis), HAZID (Hazard Identification), What-If analysis and of course checklists. HAZOP is more subjective rather than quantitative.

The HAZOP technique is  designed to identify the intentions and deviations of a particular operation, called a node. For example, a node may be a section of a plant that pumps liquid from a storage tank to a reactor some distance away. Then in this node, the original intention is identified (transporting liquid from the storage tank to the reactor) and then all possible deviations are analyzed in detail. Some of these deviations may result in accidents (for example if there is a reverse flow of liquid from the reactor to the tank). This process (the HAZOP process) is known as a HAZOP Study.

You may now appreciate that a HAZOP study should be done only by skilled personnel. If an unskilled or untrained person carries out a HAZOP (using the best software or no software), the chances of doing a bad HAZOP increase manifold. Doing a bad HAZOP is worse than doing no HAZOP at all because a bad HAZOP lulls people into a false sense of security, that their HAZOP 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.