§ 27-410 Ventilation.
Spraying or dipping spaces shall be mechanically ventilated during spraying or dipping operations so that the velocity of air is at least one hundred linear feet per minute in the breathing zone of the operator, conveying air toward the exhaust hood. The ventilating system shall be of sufficient capacity to prevent the accumulation of mist or vapors. Air shall be admitted to the spraying or dipping spaces in an amount equal to the capacity of the fan or fans and in a manner that prevents short-circuiting the path of air in the working zone of such spaces. The exhaust fan control shall be interconnected with spray guns so that they cannot be operated without the ventilation system being in operation. Exhaust fans shall, in addition, be arranged to operate independently of spray guns. Ventilation equipment shall be kept in operation for sufficient length of time after spraying or dipping operations to exhaust all vapors, fumes, or residues of spraying materials from the spray, space dip space, or drying room.
(a) Ventilating ducts shall run directly to the outer air and be protected with a hood against the weather. Ventilating ducts shall be installed in accordance with the requirements of subchapter thirteen of this chapter, but shall not terminate within ten feet horizontally of any chimney outlet, or within twenty feet of any exit or any opening in an adjoining wall.
(b) Make-up air shall be supplied from a point outside the spraying or dipping space.
(c) The exhaust system from any spraying, dipping or drying space shall not be connected to any other ventilating system or be discharged into a chimney or flue used for the purpose of conveying gases of combustion.
(d) Exhaust fan blades shall be constructed of nonferrous material. Fan blades not coming in direct contact with spraying fumes need not comply with this requirement.
(e) Adequate access doors or panels, tightly fitted, shall be provided to permit inspection and cleaning of ducts.
