Each sprinkler system zone in buildings that are more than 420 feet (128 000 mm) in building height shall be supplied by no fewer than two risers. Each riser shall supply sprinklers on alternate floors. If more than two risers are provided for a zone, sprinklers on adjacent floors shall not be supplied from the same riser.
Sprinkler risers shall be placed in interior exit stairways and ramps that are remotely located in accordance with Section 1015.2.