Simplex 4098 Applications Manual page 14

WHERE NOT TO PLACE DETECTORS/SENSORS, Continued
Underwriters Laboratories (UL) has three standards for smoke detectors: one for
duct detectors/sensors, UL 268A; one for single and multiple station
detectors/sensors, UL 217; and one for system type detectors/sensors, UL 268.
Detectors/sensors should only be used in the applications for which they are
specifically listed.
The 1997 NFPA 101 Life Safety Code notes in Section 7-6.2.10, that single
station smoke detectors shall sound an alarm only within an individual living
unit or similar area and shall not actuate the building fire alarm system.
Section 7-6.1.5 states, "All systems and components shall be approved for
the purpose for which they are installed."
In addition to possible code noncompliance, the following deficiencies would
exist in a series of residential smoke detectors connected in a fire alarm
system mode:
•
Since the fire alarm system is not supervised, vandals or others could
disconnect a detector or the entire system, leaving a building without
protection. The residents would be unaware of the serious life threatening
condition.
•
Residential detectors do not latch in alarm. In other words, the detector
self-resets. One detector in alarm will sound all the detectors connected
together. It would be difficult to identify or locate a specific detector that
initially put the system into alarm after the alarm condition was cleared.
System detectors/sensors latch in alarm. They do not reset until power is
momentarily disconnected. This makes it convenient to identify the location of
the detector/sensor that caused the control panel to alarm. In addition, system
detectors are specifically designed to connect to a supervised control panel.
Two-wire detectors require a UL compatibility review to verify that the detector
and panel properly operate together. A typical life safety fire alarm system for
an apartment complex would be to use system detectors/sensors and manual fire
alarm stations in the hallways and common areas of the complex and residential
single station type detectors and heat detectors in the individual apartments. The
system detectors/sensors, manual stations and heat detectors would be connected
to a supervised control panel, sound a general alarm and automatically notify the
proper authorities that a fire condition exists. The residential detectors located
in the apartments would be interconnected only within the individual living
quarters of each apartment. These residential units would sound an alarm only in
the apartment unit.
8
firealarmresources.com