Elevator hoistways shall be pressurized to maintain a minimum positive pressure of 0.10 inches of water (25 Pa) and a maximum positive pressure of 0.25 inches of water (67 Pa) with respect to adjacent occupied space on all floors. This pressure shall be measured at the midpoint of each hoistway door, with all elevator cars at the floor of recall and all hoistway doors on the floor of recall open and all other hoistway doors closed. The opening and closing of hoistway doors at each level must be demonstrated during this test. 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.
A rational analysis complying with Section 909.4 shall be submitted with the construction documents.
The fan system provided for the pressurization system shall be as required by this section.
The fan system shall be equipped with a smoke detector that will automatically shut down the fan system when smoke is detected within the system.
The supply fan shall either be adjustable with a capacity of at least 1,000 cfm (0.4719 m3/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.
The elevator pressurization system shall be activated upon activation of the building fire alarm system or upon activation of the elevator lobby smoke detectors. Where both a building fire alarm system and elevator lobby smoke detectors are present, each shall be independently capable of activating the pressurization system.
Detection and control systems shall be marked in accordance with Section 909.14.