Positive-pressure fans: CO dangers
By Mark van der Feyst
Many positive pressure fans are powered by an internal combustion engine that emit carbon monoxide. Carbon monoxide is a gas that attaches itself to the hemoglobin in the bloodstream and blocking the oxygen from being absorbed.
When using a positive pressure fan, the possibility of filling the structure with carbon monoxide is very real. This can happen when the exhaust air is sucked into the travel path of the air being created by the fan and entering into the structure. One way to alleviate this is to add a 3- to 4-foot metal extension to the exhaust pipe. This can be fashioned at a local exhaust repair facility or at the fire department's apparatus maintenance workshop. Be sure to use a four-gas monitor to measure the levels of carbon monoxide and oxygen inside.