Use Gas Detectors to improve safety-lessons from an industrial accident
This post shows how easy it can be, to build-in safety into your plant, by using the right kind of gas detector. Continuing our “Case study” series, we show below how a simple gas detector, had it been installed, could have easily prevented a major industrial catastrophe.
The video below show the US Chemical Safety Board accident investigation of an explosion, that rocked the industrial facility of Sterigenics International, Ontario, California. Apparently, among many things that went wrong, one glaring fact that stands out was the non use of gas monitors in the facility. Even a simple gas detector based on catalytic combustion principles, that could have measured hazardous levels of explosive gas, could have prevented the incident.
Gas monitors and gas detectors can be used very effectively in preventing such kinds of accidents, to a large extent. Ignorance about usage can no longer be a reason, since there is an excellent training course on gas detectors now available. This downloadable course on gas monitors, will enable you to understand all about safety concepts like TWA & TLV, different methods of gas detection, how gas monitors work, how to select and install a gas monitor that works and how to calibrate and maintain them so that they continue to maintain your plant in a safe state.
Well, enough on that, I am sure you will check it out. Meanwhile, here’s the video. Very graphic but also very illuminating. View it and draw your own conclusions. As always, comments are welcome!
Proper Hazardous Area Classification can prevent accidents
Mention the words “Hazardous Area Classification” and most people who operate plants think, “Oh No! It means that I have to install explosionproof equipment.”
Well, nothing could be further from the truth. First of all all hazardous areas do not have explosionproof equipment (it is just one of the many ways in which one can implement protection in hazardous areas-other means like increased safety or purging can also be used-but that’s a matter for another post altogether!).
The point I am making here is that not all areas of a plant that process hazardous materials need be classified as hazardous. Hence, one must carry out a hazardous area classification exercise, not only during the design of the plant but also subsequently at intervals of one to three years.
This hazardous area classification exercise, if done correctly, can not only decrease the costs of operating plants that process solvents, explosive vapors and gases and similar materials, but also significantly reduce the chances of an accident from happening.
How can that be?
In any process plant that processes hazardous materials ( those that are potentially explosive or inflammable), there are some places, where these materials are very likely to be present and in other places, least likely to be present. Even in places where these materials are present in large quantities, it does not mean, that they can burst into flames anytime (for example, one may have thousands of gallons of Acetone, a highly inflammable liquid in a storage tank, but it may have a Nitrogen blanketing over it, so no chances of it ever catching fire). Thus, if one does a study of the various areas in such plant, that could be hazardous, one will find some areas with more likelihood of fire/explosion, some with lesser likelihood of the fire/explosion and other areas with a very very little chance of ever bursting into flames. Based on this, we can classify such areas as Division 1, Division 2 and Safe areas. If we use the IEC system then we have the classification as Zone 0, Zone 1, Zone 2 and safe.
(Note: I admit, the above is a very simplistic description of area classification. If you wish to know about this in more detail you can find a comprehensive training course on Hazardous Area Instrumentation here, that covers a lot of this stuff . Also you can take a look at the Hazardous Area Classification ebook here, a free trial can be downloaded from the link)
Nitrogen blanketing is one way of reducing the classification of an area. Another cheaper and far more simpler way for reducing the degree of classification, is the ventilation. For example if an area of a production building of a plant, does have some vessels having some hazardous liquids, but if the area is very well ventilated by having something like huge exhaust fans and blowers in it ( implying that the fumes that are explosive, will be easily dispersed outside), then the area classification can be reduced (say from a Division 1 to Division 2 OR from a Division 2 to a Safe Area). However, there is a catch. The conditions, under which this area classification was done, MUST NOT CHANGE and these conditions must be communicated to the personnel who operate the plant.
If this is not done, then disaster may loom. Have a look at a real life case, where a worker switched off a ventilation fan, in a plant building. The fan was very important in carrying away explosive fumes from inside the building to outside. The US Chemical Safety Board has made a video of this case study and posted it on their website as well as on YouTube.
You can view the video below and draw your own conclusions.
Our conclusion is simple. If the area classification has been done, with certain assumptions or conditions, then the shopfloor workers must be knowing about it. If these conditions are changed, then the original area classification done becomes NULL and VOID. If this is not understood by all and sundry, then disasters may occur.
Welcome to Industrial Plant Safety!
Welcome to this online magazine (blog) on Industrial Plant Safety ! Here, you will find a lot of useful information regarding industrial plant safety, that includes safety equipment, industrial safety systems, fire & gas systems, hazardous areas, intrinsic safety, explosion protection, safety instrumented systems and so on. In fact, everything under the sun that is related to the topic of safety in industrial plants, will be a potential topic for posting, discussion and debate.
Feel free to post your comments and bookmark using your favorite bookmarking tool; you will find most popular tool icons below every post.
For a list of posts and comments have a look at the sidebar on the right. You will see various categories and comments. You can navigate through these and access a lot of information that includes accident investigations, videos, root cause analysis, current comments and views on all topics related to safety in industrial plants.
