Section 299 - Ventilation, heating and humidity1. Every work room in a factory shall be provided with proper and sufficient means of ventilation, natural or mechanical or both, as may be necessary, and there shall be maintained therein proper and sufficient ventilation and proper degrees of temperature and humidity at all times during the working hours. If owing to the nature of the manufacturing process carried on in the factory work room excessive heat be created therein, there shall be provided, maintained and operated such special means or appliances as may be required to reduce such excessive heat.2. All machinery creating dust or impurities in quantities tending to injure the health of employees shall be equipped with proper hoods and pipes connected to an exhaust fan of sufficient capacity and power to remove such dusts or impurities; such fan shall be kept running constantly while such machinery is in use. If the board decides that such apparatus is unnecessary for the health and welfare of the employees, or that other means of protection may be provided to safeguard the health and welfare of the employees against such injurious dusts or impurities, it may adopt rules excepting such machinery from the operation of this subdivision, or prescribing such requirements as will effectuate the intent of this subdivision.3. If dust, gases, fumes, vapors, fibers or other impurities are generated or released in the course of the business carried on in any workroom of a factory, in quantities tending to injure the health of the employees, suction devices shall be provided which shall remove such impurities from the workroom, at their point of origin where practicable, by means of proper hoods connected to conduits and exhaust fans. Such fans shall be kept running constantly while the impurities are being generated or released.4. The board shall make rules for and fix standards of ventilation, temperature and humidity in factories and shall prescribe the special means, if any, required for removing impurities or for reducing excessive heat, and the machinery, apparatus or appliances to be used for any of said purposes, and the construction, equipment, maintenance and operation thereof.5. If any requirement of this section or any rule adopted thereunder be not complied with, the commissioner shall issue an order directing compliance therewith within thirty days after the service thereof. He may in such order require plans and specifications to be filed. In such case, before providing or making any change or alteration in any machinery or apparatus for any of the purposes specified in this section, the person upon whom such order is served shall file with the commissioner plans and specifications therefor and shall obtain his approval of the same.