Explosion protection and instrinsic safety

Pepperl + Fuchs have brought out a simple and effective presentation of explosion protection and intrinsic safety. Their presentation summarizes the following:

• "A hazardous location is an area in which the atmosphere is explosive or anticipated to be explosive
• Intrinsic safety dates back to 1913 following a disastrous mine explosion in England
• The Ignition Triangle consists of three components (fuel, ignition energy and oxidizer) that must be present simultaneously, and in suitable proportions, to cause an explosion.
• Minimum Ignition Energy (MIE) is the ideal ratio of fuel to air where the mixture is most easily ignited
  Any area above or below the Minimum Ignition Energy contains a smaller fraction of air or combustible gas/fuel and cannot be ignited
• Hazardous areas in North America are broken down into three classifications: Class I (flammable gases or liquids), Class II (dust), and Class III (fibers and flyings)
• The classifications are further broken down in Division 1 or Division 2 based on the probability of the materials being present in a potentially hazardous quantity
• The Division Method of North America is comparable to the Three-Zone Model practiced in Europe
• There are three basic methods of explosion protection: containment, segregation, and prevention
• Intrinsic safety is the principle of keeping the electrical energy below the MIE and is the preferred method of explosion protection for low power devices"

Download the complete presentation from this link