Specifications subject to change without notice.
Hochiki America Corporation • SPB-24N
programmed alarm obscuration reference level, a fire signal is produced. A trouble signal is generated if the beam is
more than 90% obstructed (as opposed to partially obscured by smoke).
The microprocessor also provides compensation for a change in received signal value, with time, caused by
contamination of the optics. Since such a change with time appears as a slow change in the beam signal, the
microcomputer compensates in such a manner that the signal moves closer to the reference data at a rate approximately
+1% per hour. When this compensating capability reaches a limit, the microcomputer automatically generates a
trouble signal.
A calibrated test filter is available upon request to test and verify the sensitivity setting of the projected beam smoke
detectors.
ENGINEERING SPECIFICATIONS
OPERATION,
continued
The contractor shall furnish and install, where indicated on the plans, HOCHIKI America SPB-24N Projected Beam
Smoke Detector. The detector shall have a range of 32.8 feet to 328 feet. The projected beam smoke detector shall
be field adjustable to one of the three obscuration settings of 25%, 50% or 70% per span. These settings shall be
capable of being verified with calibrated filters. Side to side spacing shall be a maximum of 60 feet on center.
The projected beam smoke detector shall posses circuitry that automatically compensates for normal ambient changes
in the intensity of the emitted beam strength. The microprocessor shall provide compensation for a change in
received signal value, with time, caused by contamination of the optics. Since such a change with time appears as a
slow change in the beam signal, the microcomputer compensates in such a manner that the signal moves closer to
the reference data at a rate of approxi1% per hour. When this compensating capability reaches a limit, the
microcomputer automatically generates a trouble signal.
The projected beam smoke detector(s) shall also signal a trouble condition if the beam has a blockage of 90% or
more than 20 seconds and automatically resets to normal when blockage is removed.
The projected beam smoke detector(s) shall be UL listed for these applications. Voltage and RF transient protection
shall be integral to the internal circuitry of the projected beam smoke detector so as to minimize false alarm potential.
To facilitate easy installation and setup, the projected beam smoke detectors shall employ signal strength indicating
LED's. Alignment shall be facilitated by turning an alignment adjustment wheel and monitoring the relative signal
strength based upon which LEDs are illuminated.
The detectors shall also illuminate a red LED, which is visible externally, when an alarm condition is indicated.
The projected beam smoke detector shall provide a Form "A" dry contact for alarm and Form "B" dry contact for
trouble.
INSTALLATION
The HOCHIKI America SPB-24N Projected Beam Smoke Detector shall be installed in accordance with the
Installa-
tion Instruction Guide provided with every unit. Refer to the applicable NFPA Standards for additional guidance on
spacing, irregular ceiling surfaces and other design considerations.
NOTE: EOLR-24 required for power supervision.
FOUR WIRE CONNECTION TO THE CONTROL PANEL
