Mobile Computers-I-Safe

I-Safe Mobile Computers are devices which have been specially designed to meet or exceed rigorous certification requirements for use in hazardous locations where flammable gases, vapors or liquids may be present (e.g. oil refineries, chemical plants and industrial sites). More specifically, for a fire or an explosion to occur, fuel, oxygen and a source of ignition must be present; an I-safe or intrinsically safe mobile computer assumes that fuel and oxygen are present in the facility, and is therefore designed so that electrical energy or thermal energy is never great enough to cause an ignition. ISA-RP12-6 defines "intrinsically safe equipment" as "equipment and wiring which is incapable of releasing sufficient electrical or thermal energy under normal or abnormal conditions to cause ignition of a specific hazardous atmospheric mixture in its most easily ignited concentration."

I-Safe approval certifications are made up of multiple classes, groups and divisions that correspond to the specific hazardous environment a device is approved to operate in. Each class consists of two divisions and certain classes have multiple groups. For example, Class I includes flammable gases, Class II includes flammable dust, and Class III includes flammable fibers. Each class has two divisions: 1) Division 1 where explosive material is present in the air at all times and 2) Division 2 where explosive material is stored in sealed containers and explosive material is only present for short time intervals (when a failure occurs or during maintenance). Classes I and II are further broken down into groups that correspond to the explosive properties of each specific material. For example, Group A includes Acetylene and Group E includes aluminum dust. In addition, I-Safe approval ratings differ significantly from country to country and there are multiple certification authorities including UL and ATEX; as such, a device that is I-Safe certified for use in the U.S. may not be certified in Europe.

It is important to know your I-Safe requirements when evaluating I-Safe handheld computers. For example, certain models of the Motorola/Symbol MC9090 are certified as "Class I Div 2" I-Safe while the Intermec CK31IS has the more stringent "Class I, Div 1, Groups A,B,C,D, T4" certification.