It is important to note that NFPA 72 does not require an emergency communication system to be installed. Rather, it provides the design, installation, and maintenance requirements and guidelines for systems if they are required by local codes or other governing authorities or if an owner decides to voluntarily implement an emergency communication system within a building or area.
Building and fire codes are typically the driver for when a fire alarm system is required and what features they are required to have. The requirements vary by building type and occupancy. As an example, the model codes require high-rise buildings, large assembly occupancies and schools to have emergency voice/alarm communication. This is an emergency communication system as defined by NFPA 72 and would have to comply with the applicable requirements. These systems are not necessarily mass notification systems, but they could be designed to also serve that purpose. There are currently no known requirements in the building or fire codes mandating mass notification. DOD requires mass notification through the Unified Facilities Criteria, which are the design standards for DOD facilities.
There are numerous ways to communicate information and various tools can be utilized to communicate emergency information. Just because a system or method is being used to communicate emergency information doesn't make that system an emergency communications system as defined by NFPA 72. As an example, an emergency plan may include that specific individuals be notified by telephone or by text message in the event of specific incidents. One could consider those communications to be of an emergency nature. Calling 911 to report an emergency is a form of emergency communication. Utilizing an external text message service that sends text messages to all or selected staff based on input from your computer could be considered emergency communication. The phone system or other external systems are not bound to the requirements of NFPA 72. These systems may be part of an overall emergency plan and may be connected to an emergency communications system to enhance communication as supplemental equipment.
NFPA 72 requires equipment to be listed for the purpose it is used. While requirements for mass notification were being developed in NFPA 72, Underwriters Laboratories was also developing a product standard for mass notification equipment. That product standard is UL 2572: Control Equipment for Mass Notification Systems. The standard covers control units, communication units, distributed recipient mass notification control units and dedicated targeted individual receiving equipment, high power speaker arrays, transport products which manipulate the data packets, and accessories for mass notification systems to be employed in accordance with NFPA 72.
Many of the fire alarm system manufacturers have equipment that can also provide mass notification and have received UL listing under both UL 864 (Fire Alarm Control Units) and UL 2572.
How NFPA 72 Defines Mass Notification
NFPA 72 Requirements For Mass Notification
NFPA 72 Does Not Require Emergency Communication System, But Provides Guidelines
What You Need For A Mass Notification System