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Highlights of New and/or Revised Requirements in the Ninth Edition of UL 864
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Issue 18: Highlights of New and/or Revised Requirements in the Ninth Edition of UL 864

By Larry Shudak, P.E.

Unquestionably, the ninth edition of Underwriters Laboratories Inc. ANSI/UL 864, "Standard for Control Units and Accessories for Fire Alarm Systems,"1 has and will continue to have a significant impact on fire alarm control equipment. The standard covers discrete electrical control units and accessories intended for use in combination with other appliances and devices to form a commercial application fire alarm system. These products provide all monitoring, control and indicating functions of the fire alarm system. Published September 30, 2003, with a current effective date of December 31, 2008, the new edition incorporates approximately 300 changes, including 100 pages of new requirements from the previous edition. The revisions can be categorized into the following areas:

  • Performance changes to fire alarm control equipment based upon revisions to the National Fire Alarm Code (NFAC), National Fire Protection Association (NFPA) 72;
  • Requirements to address new technologies;
  • Codified requirements for smoke control system equipment, marine use fire alarm system products and installations other than indoor dry applications;
  • Expanded releasing service requirements to cover current control related requirements for NFPA 13 (sprinklers), NFPA 15 (water spray systems), NFPA 16 (foam water systems), NFPA 17 (dry chemical), NFPA 17A (wet chemical), and NFPA 2001 (clean agents); and
  • Performance requirements based upon feedback from various aspects of the fire industry.

Some of the notable changes include: reduction in system alarm response time; improved synchronized response of visible and audible notification appliances; expanded monitoring for integrity requirements; new compatibility requirements for interconnected devices and appliances; increased software integrity requirements; off-premise signaling requirements; and the rating of products intended for installation in other than indoor dry environments.

The ninth edition of UL 864 incorporated changes reflecting the NFAC's reduction in alarm response time from 90 seconds to 10 seconds for fire and supervisory alarms. The new maximum time to activate all intended notification appliances and fire safety functions, signal off-premise transmitters (whether integral or separate) and complete all local annunciation on a system or network basis is to be no longer than 10 seconds from the activation of an initiating device. In addition, most trouble signal annunciation was standardized to be 200 seconds from the occurrence of the fault condition. Exceptions include off-premise digital alarm communication (DAC) and low power RF signaling.


Another revision resulting from a change to the NFAC is the requirement that all visible notification appliances in the same field of view and all audible notification appliances in the same notification zone operate in a synchronized manner. While products may have previously claimed visible synchronization, the ninth edition of UL 864 stipulates that all synchronized visible appliances meet the requirements of UL 1971, the Standard for Visible Signaling Appliances for the Hearing Impaired.2 Each synchronized flash for all visible appliances which the product's installation instructions specify as being synchronized on a per circuit, unit, system or network basis need to meet the maximum flash duration of 10 ms. In addition, synchronization is required for all audible appliances within a notification zone intended to sound the American National Standards Institute (ANSI) S3.41 temporal code pattern (three pulse pattern) for evacuation. Notification appliance circuit (NAC) performance is verified during over and under input voltage conditions, high and low ambient temperature conditions, high humidity and other efficacy tests.

Two new changes that monitor for integrity involve the system monitoring the efficacy of the battery charger and the system automatically resounding any silenced trouble signals. The battery charger must be monitored for charging voltage in order to charge the standby batteries. Any trouble signals that are silenced must be automatically reactivated, and retransmitted off-premise if applicable, a minimum of once every 24 hours. The intent of the latter change is to periodically call attention to the off-normal condition by re-annunciating silenced or acknowledged trouble signals and hopefully effecting necessary system repairs.

The standard added requirements to address compatibility concerns for interconnected devices and appliances. One area was with respect to releasing devices. Specific requirements now include the assessment for false activation using devices requiring the least amount of energy to activate. As a result, the installation instructions for the product must list the solenoids assessed for compatibility by manufacturer's name and model number.

For compatibility purposes, NACs now are required to be designated as either "regulated" or "special application." New industry-driven voltage ratings apply to regulated circuits. For example, these include Regulated (REG) 24 DC (direct current) or REG 24 FWR (full wave rectified) ratings and correspond to identical voltage ranges used to evaluate notification appliances. Therefore, a REG 24 DC rated notification appliance would be voltage compatible with a NAC employing the same REG 24 DC rating. When synchronization of the notification appliances is employed, the NAC must be either solely or additionally rated "special application" and the installation documentation will specify the compatible notification appliances by the manufacturer's name and model number. Synchronization drives NACs to the special application rating because of the unique protocols used by the notification appliances for synchronization and the need for continued performance of the NACs during the application of a single ground fault is appliance specific.


One of the more significant changes to UL 864 involves enhanced software integrity assessment requirements. The manufacturer is required to demonstrate compliance through performance based testing that 100 percent of the product software functions, along with verification that incorrect message and entries are processed appropriately. In addition, initial site-specific programming or any subsequent reprogramming of a protected premises unit now requires manual activation of a security means at the protected premise unit. Once activated, programming may be completed on-site or downloaded from a remote location. Exceptions include programming of the telephone numbers for a digital alarm communicator transmitter (DACT). The intent is to ensure someone is on site to address any retesting described in the NFAC.

Performance requirements were added to respond to technologies now used in fire signaling. One of the more prominent technologies is the use of the Internet. Requirements were added to address monitoring for integrity, throughput and signaling.

In response to requests for products rated for outdoor environments, the ninth edition added requirements to assess products rated for outdoor dry, damp or wet, as well as indoor damp or wet locations, and products rated for indoor dry locations at prevailing ambient in excess of 25°C. Products are required to be marked with the intended installation environment. Products intended for outdoor environments or for indoor environments where the prevailing ambient is in excess of 25°C will additionally be marked with the maximum prevailing installation ambient temperature.

A complete summary of all the revisions to UL 864 can be found at the Underwriters Laboratories Inc. Web site,

Larry Shudak is with Underwriters Laboratories Inc.

  1. UL 864, "Standard for Control Units and Accessories for Fire Alarm Systems," Underwriters Laboratories, Northbrook, IL, 2003.
  2. UL 1971, "Standard for Signaling Devices for the Hearing Impaired," Underwriters Laboratories, Northbrook, IL, 2002.

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