{"id":1264,"date":"2013-07-29T12:09:49","date_gmt":"2013-07-29T11:09:49","guid":{"rendered":"https:\/\/blog.wika.com\/en\/?p=1264"},"modified":"2022-11-29T12:43:31","modified_gmt":"2022-11-29T11:43:31","slug":"ex-d-ex-i-care","status":"publish","type":"post","link":"https:\/\/blog.wika.com\/en\/knowhow\/ex-d-ex-i-care\/","title":{"rendered":"Ex-d vs Ex-i … why should I care?"},"content":{"rendered":"

I was a freshly graduated mechanical engineer when I started my career in the maintenance department of a petrochemical plant. One of the many jobs that we needed to attend to was checking the status of the pressure transmitters that were installed on our production lines, making a list of the points that needed attention (i.e. transmitters that were no longer functioning) and then writing up a request sheet for our purchasing team to acquire the replacements.<\/strong><\/p>\n

One of the more confusing parts in that process was reading the \u201cEx Marking\u201d on the label of the transmitter – it usually looked something like this: After reading about the subject and asking some of the more-experienced engineers on site, I was able to learn how to understand that code better; but I was then faced with a dilemma: some transmitters on site had a type of protection designated as Ex-ia (Intrinsically Safe) and others were designated as Ex-d (Flame-proof)\u2026 why? And what are the main differences between the two types? In this short post – and a few coming ones – I will try to shed some light on how the two types of transmitters are different, and some issues that you should keep in mind when dealing with them in your plant. \u00a0<\/p>\n

What should be used where?<\/h4>\n

One important difference between the \u201cEx-d\u201d and \u201cEx-ia\u201d transmitters is their suitability for different zones. The hazardous locations are classified (in accordance with ATEX 94\/9\/EC) into 3 different zones of application, based around the occurrence of dangerous atmospheres within the classified areas:<\/p>\n