Electrical equipment in hazardous areas the participation of operations, maintenance, safety, electrical and instrumentation professionals, the use of process diagrams and material flows, MSDS and any pertinent documents, information and knowledge to determine the hazards and their extent and the countermeasures to be employed. Area classification documentations are reviewed and updated to reflect process changes. Soon after the introduction of electric power into coal mines, it was discovered that lethal explosions could be initiated by electrical equipment such as lighting, signals, or motors. The hazard of fire damp or methane accumulation in mines was well known by the time electricity was introduced, along with the
DAMP Project in New Jersey so that it could be evaluated and a summary report be forwarded on to the project sponsor, ARPA. During this period of operation, communications via satellite did not yet exist. As a result, communications between the DAMP ship and New Jersey was through the use of single-sideband (SSB) radio, generally through the use of a 10 kW transmitter. The DAMP ship generally transmitted upper sideband (USB) voice and/or lower sideband (LSB) frequency-shift keying radioteletype in the area of 16 and 22 MHz when atmospheric conditions were favorable. When communications became difficult because of atmospheric conditions, the DAMP