In Compliance | NFPA 13
Designing a fire protection system for an airport terminal building
BY BRIAN O'CONNOR
Airport expansion and construction are being fueled by a number of factors, among them economic globalization and the worldwide growth in the number of people who regularly travel by air. A common question that we receive here at NFPA has to do with designing the proper fire suppression system for an airport terminal building.
Airport terminals are unique and complex buildings that serve a variety of functions and represent an array of potential hazards. Terminals include air travel-specific components such as departure gates, baggage handling areas, and security facilities, as well as consumer amenities that include food courts, retail stores, and lounges. Airport terminal buildings can house large numbers of people carrying combustible loads in the form of luggage, and when delays occur and departure gates become temporary sleeping areas, the potential combustible load can become even more concentrated. Just outside terminal buildings, large fuel trucks and fully fueled aircraft represent potential fuel spill points and fire hazards. All of these factors can contribute to a complicated approach to fire protection design.
NFPA standards including NFPA 13, Standard for the Installation of Sprinkler Systems, and NFPA 415, Standard on Airport Terminal Buildings, Fueling Ramp Drainage and Loading Walkways, provide requirements and information on protecting these complex buildings and the people who use and work in them. Airport terminals fall under the “Special Occupancy” category in NFPA 13, which is covered in Chapter 26 of the 2019 edition. This chapter contains sprinkler criteria from codes and standards outside of NFPA 13 so that users can have all of the information in one place. In the case of airport terminal buildings, the sprinkler requirements from NFPA 415 are extracted into section 26.25 of NFPA 13. It is important to recognize that there are many requirements of NFPA 415 that are not extracted into NFPA 13 that need to be followed, such as the NFPA 415 provision that only requires sprinklers to be installed in airport terminals where the assembly occupancy portion of the building is larger than 12,000 square feet.
There are a couple of things to keep in mind as you apply requirements for special occupancies. Most importantly, you still have to comply with the provisions of design criteria in NFPA 13, but when the requirements of the reference standard, such as NFPA 415, differ from NFPA 13 requirements, the reference standard takes precedence.
One of the topics covered by NFPA 415 addresses the protection of window openings. The radiant heat from a serious fuel spill fire can be expected to break glass windows 75 feet away, and can potentially ignite combustible materials within the building. If a window is within seven feet of the finished floor and within 100 feet of a potential fuel spill point, then the entire opening is required to have either a water spray system installed in accordance with NFPA 15, Standard for Water Spray Fixed Systems for Fire Protection, or a fire shutter system installed to protect that window and the occupants behind it.
Normally it is up to the engineer of record to determine the occupancy hazard, but NFPA 415 requires any passenger handling area to be classified as an Ordinary Hazard Group 1 Occupancy, while baggage, package, and mail handling areas are classified as an Ordinary Hazard Group 2 Occupancy.
Another unique aspect of an airport terminal is its aircraft loading walkways. These connect the terminal building to aircraft by reaching over the apron, the area where the aircraft are parked and fueled. Because of the potential for a fuel spill, these walkways are required to provide a safe means of egress for at least five minutes under fire exposure conditions similar to a jet fuel spill fire. This is typically accomplished by having the walkway meet certain construction design requirements. If the walkway does not meet those requirements, an alternate means of protection can be accomplished by providing fixed fire protection to the exterior of the walkway in the form of a water spray or foam system.
While designing a fire protection system for an airport terminal building can seem daunting, NFPA 13 and NFPA 415 are here to help guide you through the process.
Brian O’Connor is a fire protection engineer at NFPA. NFPA members and AHJs can use the Technical Questions tab to post queries on NFPA 13 at nfpa.org/13. Top photograph: Getty Images