6.4* Smoke Detection for Automatic Control.
6.4.1 Testing. All automatic shutdown devices shall be tested at least annually.
6.4.2* Location.
6.4.2.1 Smoke detectors listed for use in air distribution systems shall be located as follows:
(1) Downstream of the air filters and ahead of any branch connections in air supply systems having a capacity greater than 944 L/sec (2000 ft3/min)
(2) At each story prior to the connection to a common return and prior to any recirculation or fresh air inlet connection in air return systems having a capacity greater than 7080 L/sec (15,000 ft3/min) and serving more than one story
