Airborne concentrations explosive limits

IDLH Immediately Dangerous to Life or Health levels indicate that exposure to the listed concentrations of airborne contaminants is likely to cause death, immediate or delayed permanent adverse health effects, or prevent escape from the contaminated environment. IDLH levels are established to ensure that the worker can escape from the contaminated environment in the event of a failure of respiratory protection. An indication of "10% LEL" indicates that, for safety considerations, the IDLH was based on an atmospheric concentration of ten percent of the lower explosive limit even though toxicological impacts might not appear until higher concentrations are reached. 

Unfortunately, cold cleaning cannot be a process in which zero energy is added. Although the deaning solvent is not to be heated, it may be necessary to provide cooling in order to control its airborne concentration in the workplace to meet two requirements (1) less than 25 percent of the lower explosive hmit (LEL), and (2) as dose as possible to the 8-hour exposirre limit. 

Engineering Controls Use explosion-proof ventilation equipment. Facilities storing or utilizing this material should be equipped with an eyewash facility and a safety shower. Use adequate ventilation to keep airborne concentrations low. Exposure Limits ... 

Most powders and dusts found in industry can explode when mixed with the right amount of oxidant. For a dust cloud to explode dust must be explosible and airborne dust cloud must be present in an atmosphere capable of supporting combustion and in contact with an ignition source of sufficient energy size distribution of airborne particles must be capable of supporting flame propagation concentration of dust particles must be between the Lower Explosibility Limit (LEL), typically 20 to 100 g m, and Upper Explosibility Limit (UEL), typically in excess of 2000 g m. ... 

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