UL 1971:2018-08-29 Signaling Devices for the Hearing Impaired.
1.1 These requirements cover emergency-signaling devices for the hearing impaired. The devices and/or systems covered by this standard are suitable for use in a controlled environment, or in an uncontrolled environment as indicated in the product marking. These devices are to be used in accordance with the requirements of the National Fire Alarm Code, NFPA 72.
1.2 A signaling device as covered by these requirements consists of a unit assembly of electrical parts having provision for the connection of power supply circuits routed through the equipment by a prescribed scheme of circuiting. Also included are circuits that extend to separate devices by which additional units are actuated for signals. An installation wiring diagram attached to the product, or referenced in the product marking, indicates the devices and circuits that are acceptable for connection to the signaling device.
1.3 These requirements are to evaluate visible signaling appliances for public mode operation. These appliances are designed to alert occupants or inhabitants within the protected area. These requirements do not cover lights intended for private mode fire alarm signaling, lights intended for non-fire-alarm signaling applications, manual boxes, automatic fire detectors, or other initiating devices; nor do they cover bells, registers, or other indicating devices not provided as part of the product.
2.1.1 Except as indicated in 2.1.2, a component of a product covered by this standard shall comply with the requirements for that component. See Appendix A for a list of standards covering components used in the products covered by this standard.
2.1.2 A component is not required to comply with a specific requirement that:
a) Involves a feature or characteristic not required in the application of the component in the product covered by this standard, or
b) Is superseded by a requirement in this standard.
2.1.3 A component shall be used in accordance with its rating established for the intended conditions of use.
2.1.4 Specific components are incomplete in construction features or restricted in performance capabilities. Such components are intended for use only under limited conditions, such as certain temperatures not exceeding specified limits, and shall be used only under those specific conditions.UL 1971 pdf download.