A trip to the local mall can be an all-day event, depending on how many family members participate in the shopping spree. And the closer the shopping event is to a holiday, the better the chances are that the mall will be crowded. Designing, installing and maintaining a fire alarm system in retail occupancies, such as a mall, can be a much bigger challenge than simply shopping at one.
Before attempting the design, the wise contractor will review the applicable building and life safety code to ensure the minimum requirements for a fire alarm system as they apply to a mall are understood.
The 2006 edition of the International Building Code requires a minimum of a manual fire alarm system to be installed in a mall shopping center. The actuation of any manual fire alarm box will initiate the alarm notification appliances. The manual fire alarm boxes can be eliminated if the sprinkler system automatically activates the notification appliances upon the initiation of sprinkler water flow. The building code also allows that, during times the building is occupied, the initiation of a signal from a manual fire alarm box or from a water flow switch is not required to activate the alarm notification appliances, but this is allowed only when an alarm signal is activated at a constantly attended location from which evacuation instructions are given over an emergency voice/alarm communication system. In addition, the building code allows the emergency voice/alarm communication system to be used for other announcements, provided the fire alarm takes precedence over any other signal.
The speakers used for fire alarm notification in the mall must be provided throughout the building by paging zones. As a minimum, the building code requires that the paging zones be arranged as follows:
1. Elevator groups
2. Exit stairways
3. Each floor
4. Areas of refuge as defined in the code
Based on these building code requirements and the building code reference to NFPA 72, the emergency voice/alarm communication system must be installed in accordance with the National Fire Alarm Code.
The challenging part of the system now becomes the voice communications requirements. NFPA 72 requires that when an alarm signal is received, there must be an automatic response by the emergency voice/alarm communications system. However, if the monitoring location is constantly attended and operator acknowledgement of receipt of a fire alarm or other emergency signal is received within 30 seconds, automatic response is not required.
The controls for the emergency voice/alarm communication system must be installed in a location approved by the authority having jurisdiction and the location must be secured to allow only authorized and trained personnel access to the equipment.
“The choice of the location for the emergency voice/alarm communications control equipment should also take into consideration the ability of the fire alarm system to operate and function during any probable single event,” reads the annex to the code. “Although NFPA 72 does not regulate either building construction or contents, system designers should consider the potential for fire in proximity to fire alarm control equipment, including remotely located control devices, to disable the system or a portion thereof. Where practical, it is prudent to minimize unnecessary fire exposures of fire alarm control equipment through the use of fire-rated construction or enclosures, limiting adjacent combustibles and ignition sources or other appropriate means.”
The speaker locations for the emergency voice/alarm communication system must be chosen to ensure both audibility of the alarm signal and the intelligibility of the voice message. This is a challenge many system installers either don’t understand or fail to meet due to a lack of communications background.
Although NFPA 72-2007, Section 188.8.131.52 states that audible and visible appliances must not be installed in exit stair enclosures, as outlined previously in the building code requirements, speakers must be installed in enclosed stairways. NFPA 72-2007 recognizes the need for communication to occupants who are in the stairway and has additional requirements regarding stairway speakers that state the speakers must be connected to a separate notification zone for manual paging only.
The speaker circuits wiring installation also lies beyond the normal wiring installation requirements for a fire alarm system. The National Fire Alarm Code requires that fire alarm systems used for partial evacuation and relocation must be designed and installed so that attack by fire within an evacuation signaling zone will not impair control and operation of the notification appliances outside the evacuation signaling zone. This feature is defined as “survivability” and goes beyond the simple mechanical protection of notification appliance circuits. Survivability can be met using any of the following methods as described in Section 184.108.40.206.2 of the NFPA 72-2007:
“(1) A 2-hour fire rated circuit integrity (CI) cable
(2) A 2-hour fire rated cable system (electrical circuit -protective system)
(3) A 2-hour fire rated enclosure
(4) Performance alternatives approved by the authority having jurisdiction
(5) Buildings fully protected by an automatic sprinkler system installed in accordance with NFPA 13, Standard for the Installation of Sprinkler Systems, and with the interconnecting wiring or cables used for the operation of notification appliances installed in metal raceways and in accordance with Article 760 of NFPA 70”
According to the annex material in NFPA 101-2009, “Fire experience in mall shopping centers indicates that the most likely place of fire origin is in the tenant space where the combustible fire load is far greater than in the mall proper. Furthermore, any fires resulting from the comparatively low fire load in the mall proper are more likely to be detected and extinguished in their incipient stages. Early detection is likely due to the nature of the mall proper as a high-traffic pedestrian way.”
Based on this information, the contractor can and should recommend to the tenants in the mall that although not a requirement of the codes, it is advisable to install smoke detectors in their spaces, especially the storage areas.
The concern of many mall operators is that there will be a false alarm that will disrupt shoppers and cause them to leave, so you can expect a request for delaying an alarm until it is investigated. You should note that notification of the fire department cannot be delayed for any reason. The occupant notification delay is called positive alarm sequence and is allowed by NFPA 72 as long as it meets the requirements of the code. First, the signal from an automatic fire detection device selected for positive alarm sequence operation must be acknowledged at the fire alarm control unit by trained personnel within 15 seconds of annunciation in order to initiate the alarm investigation phase. If the signal is not acknowledged within 15 seconds, notification signals in accordance with the building evacuation or relocation plan and remote signals must be automatically and immediately activated.
Second, trained personnel will have up to 180 seconds during the alarm investigation phase to evaluate the fire condition and reset the system. If the system is not reset during the investigation phase, notification signals in accordance with the building evacuation or relocation plan and remote signals must be automatically and immediately activated.
Additionally, if a second automatic fire detector selected for positive alarm sequence is actuated during the alarm investigation phase, notification signals in accordance with the building evacuation or relocation plan and remote signals shall be automatically and immediately activated. And if any other initiating device is actuated, notification signals in accordance with the building evacuation or relocation plan and remote signals shall be automatically and immediately activated. The system must also have a means for bypassing the positive alarm sequence.
The professional contractor will meet the challenges of installing a fire alarm system in a shopping mall by understanding the code requirements and the historical fire issues in this occupancy.
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.