OSHA Handbook for Small Businesses

Control of Harmful Substances by Ventilation

Control of Harmful Substances by Ventilation

  • Is the volume and velocity of air in each exhaust system sufficient to gather the dusts, fumes, mists, vapors or gases to be controlled, and to convey them to a suitable point of disposal?
  • Are exhaust inlets, ducts and plenums designed, constructed, and supported to prevent collapse or failure of any part of the system?
  • Are clean-out ports or doors provided at intervals not to exceed 12 feet (3.6576 meters) in all horizontal runs of exhaust ducts?
  • Where two or more different type of operations are being controlled through the same exhaust system, will the combination of substances being controlled, constitute a fire, explosion or chemical reaction hazard in the duct?
  • Is adequate makeup air provided to areas where exhaust systems are operating?
  • Is the source point for makeup air located so that only clean, fresh air, which is free of contaminates, will enter the work environment?
  • Where two or more ventilation systems are serving a work area, is their operation such that one will not offset the functions of the other?