Reassessing the Fire Hazard in Parking Structures

The code requirements for parking structures have recently encountered significant changes due to the evolving design features of parking garages and the enhanced fire hazards of modern automobiles.

Recent high-profile parking garage fires

Economic losses associated with large-scale parking garage fires can be significant. In 2018, a parking garage fire in Liverpool, UK destroyed more than 1,400 cars and the parking structure required demolition due to irreparable structural damage. In 2020, a parking garage fire at the Stravenger Airport in Sola, Norway destroyed approximately 300 cars and shut down the airport. Both fires occurred in non-sprinklered parking structures. Parking garages that meet the code definition of “open” historically have not been required to be sprinklered, including in the United States. Recent fire loss incidents have spurred code officials, code enforcement, engineers, and fire departments to question the efficacy of the codes and suppression standards currently in place.

Recent changes to parking structure fire sprinkler requirements

In reaction to recent evidence that current codes and standards were not adequately addressing the fire hazard for modern parking structures, there have been several changes that will be adopted in upcoming code cycles. The newest 2023 edition of NFPA 88A, Standard for Parking Structures, requires sprinklers in all parking structures, including open parking garages that often are not sprinklered. The 2021 version of the IBC, International Building Code, has also included more stringent requirements that now require open parking garages greater than 48,000 square feet to have a sprinkler system (903.2.10).  Past editions of NFPA 13 have described “automobile parking and showrooms” as Ordinary Hazard, Group 1. In the newest 2022 edition of NFPA 13, Standard for the Installation of Sprinkler Systems, automobile parking garages are recognized as an Ordinary Hazard, Group 2 occupancy. The effect is a 33% increase in the water that a sprinkler system is required to deliver to protect the occupancy under the new standard. As of January 2021, FM Global has changed the hazard classification for parking structures form HC-2 to HC-3. Recently released editions of the IBC, NFPA 88A, NFPA 13, and FM Global all take measures to increase the requirements for fire sprinkler protection of parking structures.

Vertical stacking parking solutions present additional risk

Mechanically operated parking stackers and automatic retrieval parking systems are becoming increasingly commonplace in densely populated areas. Vertically stacked automobiles present a drastically increased fire hazard relative to single stacked vehicles. Fire sprinkler design criteria for car stackers and car lift systems was not specifically addressed in NFPA 13 until the 2016 edition. As a result, some individual cities have taken it upon themselves to develop design manuals specific to their jurisdiction (Portland, Oregon and San Francisco, California are two examples of cities that created their own design manual). Recent editions of NFPA 13 have begun to address the topic of car stackers, but the guidance is still limited. NFPA 13 now provides prescriptive guidance for protecting car stackers up to 2 cars high that requires sprinkler protection at each level of car storage. The 2021 edition of IBC requires mechanical-access enclosed parking garages to be protected by a “specially engineered automatic sprinkler system” (903.2.10.2) and includes requirements for separation, smoke removal, fire department access doors, and a fire control equipment room (406.6.4) in this occupancy. International Codes and standards or individual jurisdictions will continue to build on the prescriptive design criteria for car stacking systems, but it is also likely that the industry will rely on fire protection engineers to provide performance-based designs for the unique fire hazard associated with high-density automobile storage systems.

Learn more about the evolution of automobile manufacturing and how changes impact the fire risk of modern cars: The Evolution of Automobile & Parking Garage Hazards