EXCELLENT video for those of us that have Hazardous Locations and utilize "explosion proof" equipment. This is the type of equipment that contains an explosion within the device and does NOT allow the flammable atmosphere outside the device to be ignited. This video CLEARLY shows how easy it is to DEFEAT this safety critical feature, simply by scar the flange edge! I bet you will use this for your maintenance training, if you have not already incorporated Hazardous Location and Equipment training already!!!!
Many thanks to my auditor buddy "Chuck" with BR for sharing this with the SAFTENG family.
This article is from RKI Instrumentsand does about the best job discussing the difference between “Explosion Proof” and “Intrinsically Safe”.
Electrical equipment sometimes must be installed in areas where combustible vapors and gases are used or may be present. These are commonly referred to as “hazardous locations”, and are defined by the National Electrical Code (NEC) in the US, or the Canadian Electrical Code (CEC) in Canada. When equipment must be installed in hazardous locations, there are strict requirements for the construction of the installation, including materials and design requirements. To prevent inadvertent ignition of flammable gases and vapors by electrical equipment, the two most common methods of protection are “Explosion Proof” and “Intrinsically Safe”. We will discuss these methods as they relate to gas detection equipment.
An “explosion proof “ classification for a sensor/transmitter means that the housing has been engineered and constructed to contain a flash or explosion. Such housings are usually made of cast aluminum or stainless steel and are of sufficient mass and strength to safely contain an explosion should flammable gases or vapors penetrate the housing and the internal electronics or wiring cause an ignition. The design must prevent any surface temperatures that could exceed the ignition temperature of the gases or vapors covered by its Group rating (see below). If the sensing element is a high-temperature device (e.g. Catalytic bead or “pellistor”), it may be protected by a flame arrestor to prevent the propagation of high temperature gases to the ambient atmosphere.
The North American classifications for hazardous locations as related to flammable gases and vapors:
Class I: Gases and vapors
Division 1: Gases or vapors are usually present and/or may be present at any time in sufficient concentrations for an explosion hazard.
Division 2: Gases or vapors are not normally present and are present only in the event of a leak in some kind of containment vessel or piping, again in potentially hazardous concentrations.
Groups A, B, C, D: Groups of atmospheres categorized by the volatility and/or ignition temperatures. “A” is the most hazardous and “D” is the least hazardous group for gases and vapors.