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.

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!