Section 73A(5)(f) in The M.P. Factories Rules, 1962
(f)The fresh air admitted into the oven or drier by means of the safety ventilation system shall be circulated adequately by means of circulating fan or fans through all parts of the oven or drier so as to ensure that there are no locations where the flammable substance can accumulate in the air become pocketed to any dangerous degree.