Elevator hoistways shall be pressurized to maintain a minimum positive pressure of 0.04 inches of water column and a maximum positive pressure of 0.06 inches of water column with respect to adjacent occupied space on all floors. This pressure shall be measured at the midpoint of each hoistway door, with all ground floor level hoistway doors open and all other hoistway doors closed. The supply air intake shall be from an outside, uncontaminated source located a minimum distance of 20 feet (6096 mm) from any air exhaust system or outlet.
The fan system provided for the pressurization system shall be as required by this section.
A separate fan system shall be used for each bank of elevators.
The supply fan shall either be adjustable with a capacity of at least 1,000 cfm (.4719 m 3 /s) per door, or that specified by a registered design professional to meet the requirements of a designed pressurization system.
The pressurization system shall be provided with standby power from the same source as other required emergency systems for the building.