Flammable gases/vapors

Flammable gas or vapor-air mixtures Due to their low minimum ignition energies (<1 mj), avoidance of effective ignition sources in flammable gas or vapor-air mixtures is in principle possible only in exceptional cases. For hot surfaces a maximum permissible surface temperature Tmax must be specified, with the help of the minimum ignition temperature (MIT) of flammable gases, vapors, or liquids, so that the temperature of all surfaces is not exceeded (Table 23-8). 

Class I, Division 1—Where ignitable concentrations of flammable gases (vapors) can exist ... 

Fine Print Note No. 2 in the Code states where ignitable concentrations of flammable gases (vapors) can exist continually or for long periods of time, electrical equipment should be avoided altogether, or, intrinsically safe systems should be used. 

Where ignitable concentrations of flammable gases (vapors) are not likely to occur during normal operations, and if they do occur, they will exist for only a short period of time. 

Class I Division 2 Locations in which flammable gases, vapors, or volatile liquids are processed but are normally contained within closed systems or ignitable concentrations are normally prevented by forced ventilation or the location is adjacent to a Class I Division 1 location and an ignitable concentration of gas or vapor might occasionally be communicated to it. 

Division 1. Location where flammable gases or vapors may exist under normal operating conditions, or under repair or maintenance conditions. Division 2, Location where flammable gases, vapors, or volatile liquids are handled in a dosed system with suitable equipment, or where hazardous concentrations are normally prevented by positive mechanical ventilation areas adjacent to Class I, Division 1, from which fumes might occasionally drift. 

Ventilation — Exhaust hoods at the arc, fans, and open spaces all help to reduce the concentration of hazardous fumes, gases, and dusts, and prevent the accumulation of flammable gases, vapors, and dusts that could cause fire. Know the symptoms of fumes and gases and get out of the area if they develop. Perform atmospheric tests. 

Fire protection — Wear flame-resistant clothing. Have someone be your fire watcher when you weld. Move all combustible material at least 35 feet from the work area and try to move away from combustible materials, or cover them with fire resistant material. Don t weld in atmospheres containing dangerously reactive or flammable gases, vapors, liquids, or dust. Clean and purge containers which may have held combustible material before applying heat. Get a hot work permit and follow its safety precautions. 

CLASS 1 DIVISION 1 Flammable Gases, Vapors, or Liquids (Acetylene, Hydrogen, Ethylene, Propane) Oil Refinery, Paint Warehouse Spray Booth, Offshore Oil Rig... 

Are industrial trucks that operate wha e flammable gases, vapors, combustible dust, or ignitable... 

Explosion-proof vacuum cleaners are specifically designed for use in areas where the presence of flammable gases, vapors or finely pulverized dust in the atmosphere are sufficient to create a threat of explosion or fire. The design of the vacuum must be legally certified and evaluated for hazardous locations by a Nationally Recognized Testing Lab (NRTL) approved by OSHA. Although many vacuum companies claim to offer explosion proof vacuums, it is imperative that you ask for proof of NRTL certification. 

UNCONFINED EXSPLOSION FUEL Flammable gases, vapors, dusts, mists, explosives/unstable compounds... 

Never conduct hot work in the presence of explosive atmospheres (mixtures of flammable gases, vapors, liquids, or dusts with air), or on a metal partition, wall, ceiling, or roof with a combustible cover. 

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