What is the reason for an explosion proof telephone?
Simply put, explosion proof apparatuses including Telephones, Page/Talk Stations, Talk/Back Stations, Loudspeakers and Ringers are used to protect lives and property in hazardous locations (Class I Division 1 and Class II Division 1 areas).
The design and strength of the enclosure of an explosion proof apparatus controls ingress and egress of a substance’s ability to enter or exit it.
For a fire to start there has to be three elements present – oxygen, heat and fuel. A small spark in a confined room, vessel, building or area where combustible dust particles are present in sufficient quantities and concentration can lead to rapid combustion.
“These five factors (oxygen, heat, fuel, dispersion, and confinement) are known as the “Dust Explosion Pentagon”. If one element of the pentagon is missing, an explosion cannot occur.” – OSHA Fact Sheet, March, 2008
Throughout the world Standard Development Organizations (SDOs) including the National Fire Protection Agency (NFPA) and National Electrical Manufacturers Association (NEMA) work to formulate health and safety standards from electrical codes (NEC) and standards to test methods and product specifications.
Governments in turn have passed laws requiring strict adherence to these codes and standards within their jurisdiction.
Guardian’s EXT-401 Explosion Proof Telephone, CE20 Ringer, SR40/SR60 Speaker/Ringer, EXP & EXP-A Page/Talk Stations, EXP-TBA Talk/Back Stations and OEM Loudspeakers are all designed to operate on standard telephone voltage while containing internal detonations if they occur and keep combustible elements out.