Ask the Expert with Ray Grill
Ray Grill, PE, FSFPE, LEED AP, knows his way around fire and life safety design, especially when it comes to integrating mass notification (MNS) and emergency communications systems (ECS) with fire systems. Grill, principal at Arup, a global engineering and consultancy firm, is a licensed fire protection engineer and mechanical engineer and has been a member of NFPA 72 technical committees for more than 30 years. He currently serves as the chair of the Technical Committee on Notification Appliance. Based on his 30 plus years’ experience in fire protection engineering, emergency communications, life safety, and code consulting, he has a good understanding of the code issues and challenges involved in integrating communications systems.
How has the need for integrating ECS with fire and life safety systems changed within the past 20 years?
Although MNS and ECS are not the same and have different purposes, they are essentially integrated in the same manner.
The incorporation of MNS in buildings was first required by the Department of Defense as a result of an attack in Saudi Arabia in 1996. Shortly thereafter, the Air Force petitioned NFPA to address the design and installation of MNS with the goal of revising NFPA 72 to allow integration with the fire alarm system. As a result, the NFPA included MNS by expanding the scope of the Signaling Systems for the Protection of Life and Property Project. We now have the new Chapter 24, Emergency Communication Systems, for NFPA 72-2013, which includes the requirements for emergency/voice/alarm communication systems, mass notification, and firefighter communications.
NFPA 72, Chapter 24 does not require an ECS or MNS to be installed. Instead, it gives requirements on how to design, install, and maintain the system in accordance to NFPA 72, when it is either required by a building or fire code or implemented on a voluntary basis.
There is also the new UL 2572 mass notification standard (similar to the UL 864 standard to test fire alarm control units), an equipment standard that sets the criteria for how the control units for MNS will be designed and tested.
Mass notification functions can be incorporated into a fire system compliant with UL 864. In the 2013 edition of NFPA 72, Chapter 24 also references UL 2572, “Mass Notification Systems.” This has prompted many fire alarm system manufacturers to pursue listing to both UL 864 and UL 2572.
Where do you start when designing and integrating ECS with a fire/life safety system?
Design begins with identifying the emergency risks specific to the facility.
When designing an ECS that will address more than fire events, the risk analysis helps identify what you need for the ECS components.
The challenge with any ECS design is that each system has unique features and operational requirements to fit the emergency plan of the facility. Unlike fire alarm system design, there aren’t specific requirements that identify the features to be provided. The risk analysis and emergency plans provide the basis for design. Essentially, the ECS design and the emergency response plan need to be coordinated and integrated.
It’s ideal to start with fire system requirements and then identify any other hazards or events that may threaten the facility, which will drive the ECS integration. At a minimum, the system will have control equipment to serve as the pivotal point of the ECS.
ECS components can provide outputs to other systems that can enhance emergency communication and safety. Other systems may include phone and computer systems, closed circuit television systems, and other building systems. There is really no limit to what systems may be integrated with ECS as long as they do not interfere with the performance of fire alarm functions. The indirect benefit is that the fire alarm system can serve as the foundation of the entire ECS that would be tested and maintained as dictated by NFPA 72.
“There is really no limit to what systems may be integrated with ECS as long as they do not interfere with the performance of fire alarm functions.”
— Ray Grill, Principal at Arup
Many times, the target audience will drive the selection of appliances, such as speakers, horns, strobes, and textual displays. If voice instruction is part of the emergency plan, then speakers are required, and messages are required to be intelligible.
What types of design challenges have you experienced?
Intelligibility is often an issue that arises. The perception by many is that NFPA 72 requires a quantifiable measurement of intelligibility. Although it was proposed and debated on requiring a measurable intelligibility standard, voice messages need only be clear and understandable.
The code explicitly indicates that quantitative measurement is not required. A new Annex D in NFPA 72 on voice intelligibility provides great information on designing for intelligible voice and provides guidance if someone wants to do a quantitative measurement.
The AHJ – in conjunction with the installer and designers – determines the messaging is clear and understandable. Code requirements for audibility should not be confused with intelligibility. Alert tones that precede voice instructions are required to comply with audibility requirements of NFPA 72.
Other possible design challenges involve site-specific issues such as incorporating existing equipment as part of an ECS. While these create design challenges, there can be significant value realized by incorporating existing communication tools as part of a facility ECS. Also, because emergency communication features are not code-mandated, there are many different ways to provide communication to a target audience. Providing implementation options in a layered approach (easiest to implement first) can help an owner understand and budget for a system that would achieve their goals.
What are the options when designing ECS for existing buildings?
The approach differs when designing for an existing facility as opposed to a new structure. There may be existing communication tools that can be incorporated into the ECS. This may include radio, telephone, computer, and other systems. There may also be an emergency plan in place that provides the outline for the basis of ECS design. Existing fire alarm equipment may be utilized as a foundation for an ECS. If existing equipment is not capable of performing the required functions, then a new system with the required features may be implemented or a separate MNS can be installed.
Whichever approach is taken, existing emergency plans should be reviewed to confirm that current risks are addressed and that the ECS system will provide the emergency communications to adequately notify the target audience.
“Whichever approach is taken, existing emergency plans should be reviewed to confirm that current risks are addressed and that the ECS system will provide the emergency communications to adequately notify the target audience.”
— Ray Grill, Principal at Arup
How do you recommend bridging the gap between the recently passed code and the previous edition still being followed?
Even though ECS has now been part of the NFPA 72 code for a while, there is still a deep learning curve when it comes to MNS/ECS fire integration design. Many haven’t even started using NFPA 72-2010 yet.
While the 2013 edition may not be adopted or applicable for some time, it provides state-of-the-art criteria for the design, installation, and maintenance of fire alarm systems. Most jurisdictions are willing to accept design criteria based on a newer edition of the code if asked.
There are a few jurisdictions that apply the 2010 edition. That number will increase as jurisdictions adopt the 2012 edition of the International Building Code, which references NFPA 72-2010.
Learning the new code will also prepare you for implementation of the new code requirements when they do become applicable for your projects.
