A combustible dust has a lower flammability limit in air at 20C of 1.2% by volume. A dust extraction system operating at 3 m3=s is found to have a dust concentration of 1.5% by volume. What minimum...

A combustible dust has a lower flammability limit in air at 20C of 1.2% by volume. A dust extraction system operating at 3 m3=s is found to have a dust concentration of 1.5% by volume. What minimum flow rate of additional air must be introduced to ensure safe operation?