Emergency notification systems: Best practices for specifying in schools

09/22/2013


Mass notification

Mass notification systems (MNS), as referenced in Table 1, are systems that provide real-time information/instructions to people in a given area or building in the form of voice communications, visual signals, textual/graphical/tactile communications, or other methods with the intention of aiding in protecting lives during an emergency situation (Unified Facilities Criteria 4-021-01). These systems should consist of multiple methods or layers to ensure that the appropriate parties are notified of the emergency situation at the right time, as shown in Table 2.

These layers, or combination thereof, shall be used to address threats identified in the risk analysis as well as the emergency response plan as deemed appropriate by the design team. The use of multiple layers can aid in increasing the reliability of the notification system. It is important for designers to understand the owner’s goals in specifying the notification layer(s) for the different potential emergency scenarios.

Figure 2: Mass notification alerts distributed via personal computers can be tailored to the specific facility. Courtesy: Siemens Industry Inc. Building Technologies DivisionThe sequences of operation and activation methods for MNS are considerations for the team to integrate into the design. NFPA 72 leaves the decision of whether in-building MNS should be manual or automatically initiated to the designer. Regardless, upon activation, visible notification must be active in addition to the pre-recorded message or live voice announcement. The priority of messages/announcements, including differentiation between fire alarm and mass notification, is to be compliant with the emergency response plan and shall consider that a fire event may no longer be the highest priority.

Another thought to be considered by the design team is whether the activation shall be password-protected or if manual means such as panic button are permitted. NFPA 72 does not limit the designer to one way or another; however, the secure access method must be in accordance with the risk analysis and emergency response plan.

Notification

Many of the requirements that are applicable to fire alarm notification appliances also pertain to mass notification. When designers use strobes for both the fire alarm system and MNS, NFPA 72 requires:

  • Appliance must be clear or nominal white in accordance with ANSI/UL 1971
  • Appliances must be stamped/imprinted with “ALERT” or no marking (note these appliances are not permitted to be labeled “FIRE”)
  • Colored lenses are to have listed effective intensity labeled and spacing shall be reduced in accordance with the listed effective intensity accordingly. 

If there is a potential for a fire alarm system to be used for mass notification, the designer should specify visible appliances that are marked with “ALERT” to minimize the future cost impact to the owner. 

Textual, graphic, and video displays are also permitted to supplement the required strobes in accordance with NFPA 72. These displays are allowed to be used for nonemergency purposes as long as emergency notification overrides the messages. 

The design team must ensure the mass/voice notification system is designed to meet the intelligibility requirements of NFPA 72; information/instructions that are provided but cannot be understood provide little value during an emergency situation. 

Additionally, designers will now need to incorporate the requirement for instructions to be posted on the use of microphones to make live voice announcements into contract documents. The purpose of this requirement is to better inform the user of proper practices in order to reduce the possibility that the intelligibility of the announcement will be compromised due to poor technique. If live voice messages will be broadcast by authorized individuals during an emergency, an owner should consider providing these individuals with training and practice on use of a microphone.

Fire alarm control interface

Where separate fire alarm system and MNS are installed and protecting the same building or portion thereof, an interface between these systems must be provided for the purposes of coordinating communication. As part of the integration of the systems, a listed barrier gateway is required to be used to prevent the inadvertent interference with the fire alarm system reliable operation. This interface is required by NFPA 72 to:

  • Indicate failure at impaired control unit
  • Provide indication at fire alarm control unit that MNS is active
  • Cause the deactivation of fire alarm notification, as required for active MNS
  • Prevent fire alarm from disabling notification to special suppression pre-discharge
  • Alert supervising station, as required, that MNS has overridden fire alarm. 

The designer of a fire alarm system in educational facilities should consider providing the components necessary to interface with a future MNS. Providing this interface adds a minimal increase in cost during the installation. Installing a fire alarm interface after the fact is costly and generally requires an electrician to install the components, a fire alarm technician to program the new equipment, and trained staff to complete a reacceptance test of the new and existing functionality.

UL and the use of a PA system 

Figure 3: Nonemergency messages overridden by emergency occupant notification on visual message displays. Courtesy: Valcom Inc.When specifying products and manufacturers in contract documents, designers must be aware that NFPA 72 now requires MNS control units to be listed for their purpose. Non-listed devices are permitted to be used for the activation of a MNS if no such listed apparatus is available and the failure will not disrupt the MNS operation. 

A frequent query is whether the public address (PA) system can be used for emergency communications if such a system is not listed for this application. NFPA 72 does permit a PA system to be used for mass notification as long as the designer evaluates the PA system and determines it meets the performance requirements of NFPA 72 ECS chapter and the emergency response plan for the facility. 

Similarly, the building ECS is permitted to be used for nonemergency functions. This eliminates the need to install redundant public address and emergency communications systems, and can help reduce the construction cost for implementation of emergency communications.



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