Interesting occupancies for fire detection

Hotel and casino fire-alarm systems can prove challenging from at least three perspectives: first, the number of people moving about the facilities throughout the day and night who typically have no familiarity with their surroundings; second, the high ambient-noise level inherent with any assembly occupancy like a casino; and third, the need to integrate the fire-alarm system with other safety or security-related systems.

The first challenge requires that the fire-alarm system provide correct alarm information to personnel at the fire command center, ensuring that the occupants receive precise emergency directions. Correct alarm information will also assist the emergency response team to locate the source of the alarm and potential fire as soon as possible. This will require reliable identification of the alarm using addressable, point-identification technology.

Essential elements

An installing contractor must precisely coordinate the device labeling with both the fire department and the casino fire-protection staff. The contractor must also carefully and precisely program the operation of the system. Labeling and programming become two key factors that will ensure the transmission of accurate information to the fire command center and also that the fire-alarm system operates correctly during an alarm condition. The contractor must take responsibility that the vendor with whom he or she chooses to work will cooperate with all concerned.

A typical fire-alarm system for this mixed-occupancy group will consist of a fire alarm/voice communications system, meaning that either live or recorded voice announcements will serve as the primary method to direct occupants to safe exits. Obviously, the announcement must not direct the occupants in the direction of the fire and must contain clear information presented in an intelligible manner and with enough volume for all of the occupants to hear. Meeting these criteria for the voice announcement will present the second challenge with which the contractor and designer must wrestle.

The National Fire Protection Association’s NFPA 72-2002, National Fire Alarm Code, section 7.4.2.1 requires “that audible public mode signals are clearly heard …” and “they shall have a sound level at least 15 decibels (dB) above the average ambient sound level or 5 dB above the maximum sound level having a duration of at least 60 seconds, whichever is greater, measured 1.5 m (five feet) above the floor in the occupiable area, using the A-weighted scale (dBA).” And, section 7.4.1.4 requires that “…emergency voice/alarm communications systems shall be capable of the reproduction of pre-recorded, synthesized, or live (e.g., microphone, telephone handset, and radio) messages with voice intelligibility.”

Intuitively, a contractor can only meet these requirements by using speakers placed throughout the facility. Speaker manufacturers now provide simple computer programs to assist in selecting the correct number and placement of speakers. Using software will help ensure both audibility and intelligibility. However, if the protected space has a complex geometry, a contractor should seek additional assistance from an acoustical engineer.

Another option the contractor might choose would integrate the fire-alarm system with a professionally designed public-address system. However, because these systems do not typically meet the requirements of the National Fire Alarm Code to monitor the integrity of the interconnecting circuits and amplifiers, the contractor must obtain specific approval from the authority having jurisdiction before implementing this option.

In developing precise voice announcements, the contractor must consider that in some cases the occupancy will consist of open spaces. This will make it much more difficult to define the boundaries of fire or smoke zones.

During interviews with survivors of fires in hotel/casino complexes, as well as other assembly occupancies, these people most frequently complained about the lack of information or misinformation they received during the fire. To address this complaint, the fire-alarm system must transmit clear, concise information to all areas. Also, the building code may consider the hotel as a separate building. Thus, the fire-alarm system would not transmit an alarm in the casino to the guests in the hotel and vice versa.

End-user input

The contractor’s third challenge comes from the need to work closely with the owner’s representative to understand the required integration with systems in the building, like security and fire safety. Other examples of nonfire systems include card access control, closed-circuit television surveillance, background music, building automation and time.

The contractor responsible for the fire-alarm system installation must coordinate the systems integration. A professional contractor will gladly embrace this opportunity to ensure the safety of the casino/hotel.

MOORE, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a co-editor of the current National Fire Alarm Code Handbook. Moore is a principal with Hughes Associates Inc. at the Warwick, R.I., office.