502.7.4 Dipping operations.

Flammable vapor areas of dip tank operations shall be provided with mechanical ventilation adequate to prevent the dangerous accumulation of vapors. Required ventilation systems shall be so arranged that the failure of any ventilating fan will automatically stop the dipping conveyor system.

502.7.5 Electrostatic apparatus.

The flammable vapor area in spray-finishing operations involving electrostatic apparatus and devices shall be ventilated in accordance with Section 502.7.3.

502.7.6 Powder coating.

Exhaust ventilation for powder-coating operations shall be sufficient to maintain the atmosphere below one-half of the minimum explosive concentration for the material being applied. Nondeposited, air-suspended powders shall be removed through exhaust ducts to the powder recovery system.

502.7.7 Floor resurfacing operations.

To prevent the accumulation of flammable vapors during floor resurfacing operations, mechanical ventilation at a minimum rate of 1 cfm/ft 2 (0.00508 m 3 /(s • m 2 )) of area being finished shall be provided. Such exhaust shall be by approved temporary or portable means. Vapors shall be exhausted to the exterior of the building. Such exhaust equipment shall be kept in operation while the floor finishing operations are conducted and until any flammable vapors have been exhausted to the exterior of the building.

502.7.8 Resin application areas.

Exhaust ventilation for resin application areas shall comply with Section 502.7.3.

   Exception: Mechanical ventilation is not required for buildings that are unenclosed for at least 75 percent of the perimeter.

502.8 Hazardous materials – general requirements.

Exhaust ventilation systems for structures containing hazardous materials shall be provided as required in Sections 502.8.1 through 502.8.5 and shall comply with the New York City Fire Code.

502.8.1 Storage in excess of the maximum allowable quantities.

Indoor storage areas and storage buildings for hazardous materials in amounts exceeding the maximum allowable quantity per control area, as defined by the New York City Fire Code, shall be provided with mechanical exhaust ventilation or natural ventilation where natural ventilation can be shown to be acceptable for the materials as stored.

   Exceptions:

      1.   Storage areas for flammable solids complying with the New York City Fire Code.

      2.   Storage areas and storage buildings for fireworks and explosives complying with the New York City Fire Code.