, High Expansion Foam: Risks and Rewards, Harrington Group IncOn January 8, 2014, a High Expansion Foam (HEF) fire suppression system was unintentionally activated in a Florida aircraft hangar. This unfortunate incident in Hangar 130 at Eglin Air Force Base turned to tragedy when a civilian contractor lost his life.

In the aftermath of such a shocking occurrence, the question of prevention is inevitably raised. What were the series of events that led to this result? Could it have been prevented? How can we prevent this from happening again?

It’s a discussion that starts with HEF systems’ role in modern-day special hazards fire suppression. Over the next series of blogs, we’ll discuss the purpose and advantages of HEF, the specific causes of the Eglin incident, and the conclusions and recommendations reached after the incident investigation.

What is High Expansion Foam?

HEF systems are an efficient, effective fire suppression technique used in a number of special hazard applications and are very commonly used in aircraft hangar protection. The foam generation process creates very large volumes of stable light weight foam, much like dish soap or bubble bath suds, which can cover large areas very quickly and block flammable/combustible surfaces from exposure to oxygen. In aircraft hangars, such as Hangar 130, aviation fuel spills pose a significant risk if ignited. HEF systems are uniquely suited for aircraft hangar protection since the aircraft themselves create a significant obstruction to the delivery of other extinguishing agents below the aircrafts’ large surface area.

Prior to the system actually releasing foam, several events typically have to occur. First, a fire is detected.  Then an alarm (e.g., 30-seconds duration) will warn that a fire has been detected and a foam release is imminent. Once the initial alarm warning period expires, the piping system will fill, followed by the discharge of HEF from foam generators, which (in a hangar) are typically located above the aircraft.

While there are stringent design requirements for HEF systems, including the provision of safeguards to prevent accidental activation, a system can operate unintentionally for a number of reasons, including:

  • Faulty components
  • Voltage transients
  • Freeze events
  • Water pressure surges
  • Human error

The Air Force commissioned investigation into the Hangar 130 incident certainly looked at all of these possibilities and we’ll review the key findings and recommendations from the investigation later in this blog series.