These requirements cover air duct smoke detectors intended for
indoor use within or protruding into a duct, or mounted in a
housing with sampling tubes extending into or traversing a duct.
Air duct smoke detectors are intended to be installed in ducts
where the maximum air temperature inside the duct does not exceed
100°F (38°C), nor does the minimum temperature become less than
32°F (0°C), in accordance with the Standard for Automatic Fire
Detectors, NFPA 72, and the Standard for the Installation of Air
Conditioning and Ventilating Systems, NFPA 90A.
An air duct smoke detector unit, as covered by these
requirements, is intended to detect smoke for the primary purpose
of controlling blowers and dampers of air conditioning and
ventilating systems to reduce the risk of panic and damage from
distribution of smoke and gaseous products. Each unit consists of
an assembly of electrical components, including a sensing means to
detect smoke (sensing head or projected beam assembly), sampling
tubes or equivalent (based on design), provision for connection to
a source of power, and means for generating a signal when smoke is
detected. It is not prohibited that remote control circuits be
provided. A detector shall be powered from a commercial power
source, separate power supply, or be connected to a control unit as
part of a fire protection signaling system. Duct detectors are not
intended as a substitute for open area protection.
These requirements cover detectors:
a) Intended to control air conditioning and ventilating
b) Intended for control of releasing devices, such as fire and
smoke dampers, or
c) Both (a) and (b).
These requirements do not cover:
a) Control units that are covered by the Standard for Control
Units and Accessories for Fire Alarm Systems, UL 864, to which the
air duct smoke detectors are connected.
b) Single and multiple station smoke detectors covered by the
Standard for Single and Multiple Station Smoke Alarms, UL 217.
c) Smoke detectors intended for open area protection or
releasing device service, or both, covered by the Standard for
Smoke Detectors for Fire Alarm Signaling Systems, UL 268.
d) Smoke detectors integral with combination door closers and
holders, covered by the Standard for Door Closers-Holders, With or
Without Integral Smoke Detectors, UL 228.
e) Commercial-resident detectors not intended for connection to
a system control unit that are covered by the Standard for Smoke
Detector Monitors and Accessories for Individual Living Units of
Multifamily Residences and Hotel/Motel Rooms, UL 1730.
A product that contains features, characteristics, components,
materials, or systems new or different from those covered by the
requirements in this standard, and that involves a risk of fire or
of electric shock or injury to persons shall be evaluated using
appropriate additional component and end-product requirements to
maintain the level of safety as originally anticipated by the
intent of this standard. A product whose features, characteristics,
components, materials, or systems conflict with specific
requirements or provisions of this standard does not comply with
this standard. Revision of requirements shall be proposed and
adopted in conformance with the methods employed for development,
revision, and implementation of this standard.
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