UL 268

1.1 This Standard sets forth requirements for smoke detectors and accessories, including mechanical guards to be employed in ordinary indoor locations in accordance with the following:

1. a) In Canada only:
   1. 1) Standard for the Installation of Fire Alarm Systems, ULC-S524;
   2. 2) National Building Code of Canada; and
   3. 3) National Fire Code of Canada.
2. b) In the United States only:
   1. 1) National Fire Alarm and Signaling Code, NFPA 72.

1.2 A smoke detector (e.g. ionization-type, photoelectric-type, smoke detector with supplementary heat detection type, combination smoke type, multi-criteria type) as covered by this Standard consists of an assembly of electrical components arranged to detect one or more products of combustion. At a minimum the detector shall contain a smoke (particulate) sensor. The products of combustion may consist of visible as well as invisible smoke particles, gases, heat, radiant energy, and water vapor. The detector includes provision for the connection to a source of power, signaling, and optional remote control circuits. Additional functionality, such as a heat detector, heat sensor, or audible signaling appliance/device, is permitted to be incorporated as part of the smoke detector assembly.

1.3 This standard covers the following types of detectors:

1. a) Detectors intended for open area protection and for connection to a compatible power supply or control unit for operation as part of a fire alarm system;
2. b) Detectors intended solely for control of releasing devices such as electromagnetic door holders, fire dampers or smoke dampers;
3. c) Detectors intended for both applications described in (a) and (b) above; and
4. d) In Canada, duct detectors.

1.4 Products incorporating other functions in addition to those described in this standard, shall comply with:

1. a) In Canada only:
   1. 1) Control units that are covered by the Standard for Control Units for Fire Alarm Systems, ULC 527;
   2. 2) Self-contained single and multiple station smoke detectors that are covered by the Standard for Smoke Alarms, ULC-S531;
   3. 3) A heat detector incorporated as a part of a smoke detector assembly, and covered by the Standard for Heat Actuated Fire Detectors for Fire Alarm Systems, ULC-S530 and/or when part of a multi-criteria smoke detector;
   4. 4) Fire tests for smoke detectors integral with combination door closers and holders that are covered by the Door Closers and Holders, ULC/ORD-C228;
   5. 5) Detectors for monitoring the smoke density within flues or stacks; and
   6. 6) A residential CO alarming device incorporated as a part of a smoke detector assembly, and covered by the CSA 6.19, Standards for Residential CO Alarming Devices, except when part of a multi-criteria smoke detector.
2. b) In the United States only:
   1. 1) Control units to which the detectors are intended to be connected that are covered by the Standard for Control Units for Fire-Protective Signaling Systems, UL 864;
   2. 2) Self-contained single and multiple station smoke detectors, not intended for connection to a system control unit, that are covered by the Standard for Single and Multiple Station Smoke Alarms, UL 217;
   3. 3) A heat detector incorporated as a part of a smoke detector assembly, and covered by the Standard for Heat Detectors for Fire Protective Signaling Systems, UL 521, except for the requirements of the Fire Test (Heat Detector) and/or when part of a multi-criteria smoke detector;
   4. 4) A gas and vapor detector or sensor incorporated as a part of a smoke detector assembly, and covered by the Standard for Gas and Vapor Detectors and Sensors, UL 2075, except when part of a multi-criteria smoke detector;
   5. 5) Fire tests for smoke detectors integral with combination door closers and holders that are covered by the Standard for Door Closers-Holders, With or Without Integral Smoke Detectors, UL 228;
   6. 6) Commercial-residential 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; and
   7. 7) Detectors for monitoring the smoke density within flues or stacks.

1.5 These requirements also cover all remote accessories that are intended to be connected to a smoke detector.