502.8.1.1 System requirements.
MC § 502.8.1.1
Exhaust ventilation systems shall comply with all of the following: 1. The installation shall be in accordance with this code.
2.Mechanical ventilation shall be provided at a rate of not less than 1 cfm/ft 2 (0.00508 m 3 /(s • m 2 )) of floor area over the storage area.
3.The systems shall operate continuously unless alternate designs are approved.
4.A manual shutoff control shall be provided outside of the room in a position adjacent to the access door to the room or in another approved location. The switch shall be a break-glass or other approved type and shall be labeled: VENTILATION SYSTEM EMERGENCY SHUTOFF.
5.The exhaust ventilation shall be designed to consider the density of the potential fumes or vapors released. For fumes or vapors that are heavier than air, exhaust shall be taken from a point within 12 inches (304.8 mm) of the floor. For fumes or vapors that are lighter than air, exhaust shall be taken from a point within 12 inches (304.8 mm) of the highest point of the room.
6.The location of both the exhaust and inlet air openings shall be designed to provide air movement across all portions of the floor or room to prevent the accumulation of vapors.
7.The exhaust air shall not be recirculated to occupied areas if the materials stored are capable of emitting hazardous vapors and contaminants have not been removed. Air contaminated with explosive or flammable vapors, fumes or dusts; flammable, highly toxic or toxic gases; or radioactive materials shall not be recirculated.
