Practical experience in electrical safety training that is immediately useful
Electrical safety training: equipments locate inside Hazardous Areas which is a source of ignition required safety protection . The technical term for it is intrinsic safety protection. The purpose is to minimize the risk of ignition source and there are several ways to deal with it.
Flameproof/Explosion-proof Housing: Using an enclosure which is strong enough to withstand internal explosions and have joints to be tight enough that any hot materials escaping through the joints will be sufficiently cooled to prevent ignition of the external atmosphere.
Gas Purge/Hermetic Sealing: Using pressurization technique which keeps the flammable material from entering the apparatus enclosure by maintaining the pressure inside the enclosure at a pressure higher than the external atmosphere.
Intrinsically Safe/Non-incentive Equipment: to limit the amount of available energy to a level lower than which ignite the flammable mixture.
Some reqirements to install equipment in hazadous area:
Practical experience in electrical safety training that is immediately useful
Sealing requirements - NEC Section 504-70 .
Spacing maintained between adjacent intrinsically safe circuits and any non intrinsically safe circuits is 1.97 in(5cm).
Cable shields, enclosures, intrinsically safe apparatus, raceways, if metal, shall be grounded .
Label the raceways, cable trays, enclosures.
Sparking contacts not permitted in Zone 0.
Cable entry to equipment designed to minimize risk of damage Gromet or Gland.
Cable comply with minimum conductor size.
Terminals should be identified.
Electrical designers should be consider to install electrical equipments and instruments in non-hazardous when practical. Otherwise, area of classification should be defined before select the equipments. Work with intrinsic safety experts in order to select the best intrinsic safety method that meet with the standards of National Fire Protection Association (NFPA), American Petroleum Institute (API) and the Instrument Society of America (ISA). Reference: NEC National Fire Protection Association American Petroleum Institute (API) and the Instrument Society of America (ISA) Anyone using this article should rely on your own independent judgment. This is not a professional advice.
