(3)Whenever a thunderstorm appears to be imminent in the vicinity of a magazine or store house or processes building, every person engaged in or about such magazine or store house shall be withdrawn to a safe distance from such magazine and store house shall be kept closed and locked until the thunderstorm has ceased or the threat of it has passed:Provided that process building used for manufacture of fireworks, explosives of Class 7, may not be provided with lightning conductor unless otherwise specified by the licensing authority.
