What is Explosion Proof Compliance and Why Do We Need Approved Equipment?|
Article- July 2012 By Larson Electronics.com
Larson Electronics Explosion Proof Fluorescent Paint Booth Lights
The importance of protecting against fires and explosions within the industrial workspace is a subject that cannot be stressed enough. Despite the wealth of information available and the unfortunately large numbers of documented instances of accidents, there still remains plenty of confusion regarding just what constitutes a hazardous location and the proper methods of practicing protection and prevention. In many cases operators simply make the mistake of using equipment with the wrong approvals, and in other cases fail to understand the dangers associated with their particular type of work environment. In either case, even if an accident does not occur, there are still the problems of failing to meet compliance with applicable regulations and the potential issues that can arise with insurance coverage. No one wants to be cited by OSHA or any regulating body, nor do they wish to encounter the less than enjoyable prospect of dealing with a less than satisfied insurance carrier. While such litigious issues are certainly preferable to dealing with the aftermath of an accident, they do serve to underscore just how widespread the perils of non compliance can be.
Some of the most common problems arise from a lack of knowledge or ignorance as to just what constitutes a hazardous location and why approved equipment must be used. Without an understanding of why equipment approved for hazardous locations is required, it is nearly impossible to properly protect against the dangers hazardous locations present. Equipment designed for use in hazardous locations is designed to protect against the potential for such equipment to ignite flammable or explosive vapors, gases, liquids, dusts and otherwise dangerous flammable atmospheres and materials. Some chemicals and compounds are so flammable in a gaseous or vapor form, that even the tiniest of sparks will be enough to cause ignition, leading to fires or explosions. Acetylene gas for instance is extremely flammable and easily ignited, and not only that, but has the potential to produce a great deal of explosive energy at ignition. An atmosphere within a closed garage for instance, that has been heavily contaminated with Acetylene gas, could easily be ignited by something as innocuous as a static electricity spark, resulting in an explosion powerful enough to destroy the entire structure. Thus, it is extremely important to attempt to remove any potential sources of ignition be it a tiny spark or an open flame.
All equipment to be used in a hazardous location must be approved for such locations. In order to easily determine if equipment carries the correct approval for a certain type of location, it must display documentation in a readily visible area on the device. For most explosion proof lighting and electrical devices, either a metal plate or sticker is affixed to the device which displays the various approvals and classifications the device as received. Such markings will usually note the approving testing groups, Underwriters Laboratories for instance, and the various letter and numbers which denote the different types of locations, conditions and materials the device is approved for. Such a marking would appear similar to the following although they may differ from device to device and one manufacturer to another…
When looking at such a marking you may find yourself wondering just what “Class”, “Divisions” and “Groups” mean. “Class” refers to the basic nature of the hazardous environment according to the type of materials that are present, “Division” refers to the probability of the hazard, and “Group” refers to the specific type of hazardous material present within the hazardous location. Due to the wide variety of materials, conditions and the different natures of hazardous locations, there are several different classes and subdivisions as well as groups, each designed to denote a particular part of the hazards encountered. For a full explanation of Hazardous Location Classifications, read our article on the subject here.
Another thing which is important to note is that hazardous location approvals vary by country and regions. Classifications for Canada differ from US classifications, and the EU has an entirely different set of standards as well. While it is possible to make some equivalency comparisons among them, for the most part they are not interchangeable, meaning equipment approved to US standards cannot simply be substituted for EU approvals in EU locations. Equipment must be approved for location according to the regulations and testing required by local governing bodies.
Yet another area of confusion arises from understanding just who is certified to provide approvals. In the United States, OSHA and other regulating bodies do not engage in the testing and approval of equipment, but rather work only to provide the criteria by which equipment is measured and must meet to achieve compliance. For the US, Underwriters Laboratories is one of the most well known third party groups which conduct testing and approvals. Equipment is tested for its ability to meet minimum standards for a specific type of location, and once it passes testing it is approved for use only in those locations which it is approved. So, since a device is approved “explosion proof”, it does not mean it is safe for all environments, but only that an independent testing authority has found the device suitable for use within a specifically designated set of conditions. Canada likewise has its own accredited testing groups as does the EU, and each follows a similar pattern of approval for specific locations.
Some of the biggest mistakes made in the use of explosion proof lighting and electrical equipment involve easily avoided problems based in misunderstandings or ignorance of hazardous location classification. Devices approved for use in Europe for example, are not compliant with US standards and vice versa, thus they can only be legally used in their respective countries. Equipment must also carry approvals for the type of hazardous location it is going to be operated within. A device that is rated for locations where combustible dusts are present for example is certainly not going to be suitable for areas where highly flammable gases are present. So, equipment must be matched to the type of location according to its approvals.
It is the responsibility of operators and owners to ensure that the correct equipment with the proper approvals is used within hazardous locations. Operators must familiarize themselves with the various regulations and classifications which apply to their operations, and ensure any equipment used meets compliance with applicable regulations. The costs for failing to comply can range from fines and possible shutdowns of operations, to loss of insurance coverage, to the worst possible scenarios of fires, explosions, injuries and deaths.