Forced Ventilation

When a hazardous atmosphere is present or potentially present, forced ventilation is used before entry and sometimes during entry in order to preserve a natural breathing environment. This is sometimes used in addition to SCBA's (self contained breathing apparatus's).

 Hazardous atmosphere's can include oxygen deficient and oxygen rich atmosphere's as well as toxic atmospheres resulting from chemical vapors.

Forced ventilation devices similar to the one pictured above are placed into the confined space before entry and allowed to ventilate the space until the safety attendant records permissable oxygen levels using a O2 monitor. During entry, oxygen levels are continually monitored by the entry attendant and if levels become hazardous the entry is aborted and the entrant must come out.

For more information visit the following link:
http://www.ehss.vt.edu/programs/CNF_forced_air_entry.php