Entering a confined space comes with a number of risks:
- Physical hazards: mechanical equipment, falling objects, structural collapse, etc. Historically, these account for about 20% of fatalities associated with confined space entry.
- Engulfment hazards: that’s a less horrific way to say “buried alive.” These are similar to some physical hazards, except the danger is from asphyxiation instead of being crushed. A prime example of this would be a farmworker falling into a grain silo in such a way that their head is submerged in the volume of grain. About 11% of confined space entry fatalities involve engulfment accidents. EXAIR Line Vacs are actually used in emergency responses to these.
- Atmospheric hazards: Without adequate ventilation, carbon dioxide can build up, displacing the oxygen that workers need to breathe. Toxic and flammable gases are in this category as well, and whether workers are asphyxiated or poisoned, failure to provide a safe atmosphere accounts for almost 60% of confined space entry deaths.
Before workers enter a confined space, permits are oftentimes required. Atmospheric monitoring and ventilation are key aspects of such permits: Monitoring to ensure an adequate level of oxygen and the reduction of toxic & flammable gases to safe exposure limits, and ventilation to make sure that happens. It’s generally recommended to have ventilation/exhaust equipment capable of providing 20 air changes per hour.
EXAIR Air Amplifiers are an easy & reliable choice for providing the required ventilation. With no moving parts to break or electrical components to fail, all they need is a supply of compressed air. So, how do we choose the right one? Since we know we need 20 air changes an hour, the first step is to determine the volume of the space. Let’s say we need to enter a 10ft x 6ft x 6ft tank:
- 10ft x 10ft x 12ft = 1,200 cubic feet
- 1,200 cubic feet of air X 20 changes per hour = 24,000 cubic feet of air to change per hour
- 24,000 cubic feet/hour ÷ 60 minutes/hour = 400 cubic feet per minute
In this case, we could specify a Model 6042 2″ Aluminum Adjustable Air Amplifier, which uses just 21.5 SCFM @80psig to generate a total developed flow of 430 SCFM (see table above). Minus the 21.5 SCFM of compressed air flow, that means it’s drawing 408.5 SCFM in from the tank.
EXAIR Air Amplifiers are a simple, low-cost way to move air, smoke, fumes, and even light materials. If you’d like to find out more, or if you have a potential application to discuss, give me a call.
Russ Bowman, CCASS
Application Engineer
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