By Jeff Harrington, CEO and Founder of Harrington Group, Inc.

High expansion foam (HEF) is used as an efficient and highly effective fire suppression technique, particularly within locations that pose a high risk for fuel spills. Aircraft hangars, such as Eglin Air Force Base’s Hangar 130, employ these systems with increasing regularity.

On January 8, 2014, a combination of factors led to the accidental trigger of Hangar 130’s HEF system. Within minutes, the building was filled with about 17 feet of HEF. Although emergency responders acted quickly and the building was immediately evacuated, a civilian contractor was killed when he reentered the premises with three other individuals.

Nearly everyone in the United States has been affected by this year’s extraordinary winter, and Florida was no exception. In the days before the Hangar 130 incident, the temperature at the base fluctuated multiple times around a critical number: 32 degrees. This repeated freezing and thawing led, as it often does, to increased stress on water pipes, putting the base at risk for bursts and leaks.

At several points on the morning of January 8, on-site crews discovered warning signs that the system may activate. About fifteen minutes before the incident, the inclement weather had taken its toll. A separated pipe revealed a slow leak in the building’s wet sprinkler system, leading crews to make a call to the fire department with just minutes to spare.

The system was triggered, and every employee from Hangar 130 and the proximate Hangar 129 were promptly evacuated. Soon after, though, it was determined that Hangar 129 was not at risk, and the building was subsequently cleared for access and reentry.

Soon after, four civilian contractors reentered the building via the catwalk connecting Hangar 129 to Hangar 130. At this time, emergency personnel had deemed Hangar 130 off-limits, and it was not cleared for reentry.

After taking photographs of the foam for their vantage point on the catwalk, the four individuals attempted to exit the building via the elevator, which took them to the first floor of Hangar 130. They were immediately engulfed in HEF. Two of the contractors escaped within minutes, one was subsequently found and rescued by emergency personnel, and the fourth, tragically, was unable to find his way out and ultimately went into cardiac arrest.

This tragedy demonstrates the potential health risk associated with an HEF system and the crucial importance of understanding the true nature of this risk. The foam produced by an HEF system not only inhibits sight and movement, it also partially suppresses sound. These characteristics make it very difficult for someone immersed in and surrounded by the foam to remain oriented and effectively and safely find a building exit. It also hampers rescuers as they try to search and locate someone immersed in the foam.

The incident at Hangar 130 resulted in an extensive investigation and many lessons learned. In subsequent posts, we’ll explain the investigation’s findings. HEF is a tremendous tool in fire suppression, but these systems require a great deal of knowledge and experience in order to prevent similar accidents.