Simplex 4100U Application Manual page 96

Glossary of Terms,
Glossary
Continued
Master Box – A municipal fire alarm box that may also be operated by remote means.
Multiplexing – A signaling method characterized by the simultaneous or sequential transmission,
or both, and reception of multiple signals in a communication channel including means for
positively identifying each signal.
Municipal Communications Center – The building or portion of a building used to house the
central operating part of the fire alarm system; usually the place where the necessary testing,
switching, receiving, retransmitting, and power supply devices are located.
Municipal Fire Alarm Box – A specially manufactured enclosure housing a manually operated
transmitter used to send an alarm to the municipal communications center.
Municipal Transmitter – A specially manufactured enclosure housing a transmitter that can only
be tripped remotely, used to send an alarm to the municipal communications center.
NDU – Network Display Unit.
Negative Air Pressure Technique – Pulls the smoke out of the area and vents it outside of the
building.
Non-coded Signal. – Signal from any notification appliance that is energized continuously.
Non-Compensated System. – Simply turn on a fan to pressurize the stairtower. The fan speed
does not change to compensate for doors opening and closing. The more doors that are open, the
more the pressure differential between the stairtower and the building drops.
Non-Dedicated Smoke Control Components – Consists of HVAC components within a building
which are operated regularly. The normal "comfort" level associated with the proper operation of
the equipment serves as the means of maintaining system integrity.
Non-Dedicated Smoke Control System – Uses parts of the HVAC system to control smoke.
Normal Stack Effect – An upward movement of air within the building.
Notification Appliance – Any audible or visible signal employed to indicate a fire, supervisory,
or trouble condition. Examples of audible signal appliances are bells, horns, sirens, electronic
horns, buzzers, and chimes. A visible indicator consists of a lamp, target, meter deflection, or
equivalent.
Notification Appliance Circuit – A circuit or path directly connected to an notification
appliance(s) such as bell, horns, chimes, or others.
NPU – Networking Processing Unit.
Operational Tests – Test that make sure the components and subsystems of the smoke control
system are installed correctly.
Paging System – A system intended to page one or more persons such as by means of voice over
loudspeaker stations located throughout the premises or by means of coded audible signal or
visual signals similarly distributed, or by means of lamp annunciators located throughout the
premises.
Permanent Visual Record (Recording) – Immediately readable, not easily alterable print, slash,
punch, etc., listing all occurrences of status change.
Piston Effect – Transient pressures produced when an elevator car moves inside the shaft during a
smoke emergency. This "piston effect" can pull smoke into a normally pressurized elevator lobby
or elevator; shaft.
6-6
Continued on next page