A Smarter Approach to Aircraft Hangar Fire Protection: Understanding Risk-Based Design

‍Aircraft hangars are unique structures that require specialized fire protection. Historically, these systems have relied heavily on foam-based suppression, designed to address the risk of large fuel spills. However, experience shows that these events are rare. In fact, accidental discharges of these systems are much more common, often causing significant damage to aircraft, facilities, and even the environment.

 There is a smarter, more flexible approach to hangar fire protection: the performance-based, risk assessment method.This method allows for tailored fire protection solutions based on a detailed understanding of the specific risks and operations of each hangar, rather than a one-size-fits-all approach.

The Limitations of Traditional Prescriptive Methods

Traditional code requirements prescribe specific fire protection systems for hangars, primarily based on the hangar's size and the type of aircraft it houses. This approach often mandates the installation of foam systems, regardless of the actual risk, which can lead to several issues:

• Unnecessary Costs: Foam systems are expensive to install and maintain.
• Environmental Concerns: Many foam systems usePFAS chemicals, which are emerging environmental contaminants.
• High Risk of Accidental Discharge: Foam systems are prone to accidental activations, resulting in costly damage.
• Inflexible Design: Prescriptive methods don't allow for variations in hangar use and risk.

The Performance-Based, Risk Assessment Approach: A Tailored Solution

The performance-based approach to fire protection uses a detailed assessment of the risks that are unique to each hangar. This risk assessment is a systematic evaluation of the potential fire hazards, the consequences of a fire, and the effectiveness of various fire protection measures. This approach is based on the most current edition of NFPA 409, Standard onAircraft Hangars.

Key elements of a risk-based fire protection design include:

• Identifying Stakeholders: Bringing together all relevant parties to inform the decision-making process, including the building owner, architect, fire protection engineer, insurance carrier, and the local fire department.
• Defining Project Goals: Setting clear goals for the fire protection system, such as life safety, property protection, and minimizing environmental impact.
• Analyzing Fire Risks: This step involves a thorough evaluation of factors such as:
  • The type and quantity of fuel in the aircraft.
  • The activities performed inside the hangar (e.g., storage, maintenance, repair).
  • The potential for fuel spills.
  • The value of the aircraft and the hangar.
  • The construction and compartmentation of the hangar.
  • The response time and capabilities of the local fire department.
• Evaluating Fire Protection Options: This involves comparing the effectiveness of various fire protection systems, including:
  • Automatic sprinkler systems.
  • Low-expansion and high-expansion foam systems.
  • Ignitable Liquid Drainage FloorAssemblies (ILFDA).
• Evaluating Fire Protection Options: This involves comparing the effectiveness of various fire protection systems, including:
  • Automatic sprinkler systems.
  • Low-expansion and high-expansion foam systems.
  • Ignitable Liquid Drainage FloorAssemblies (ILFDA).
• Developing a Tailored Fire Protection Plan:Based on the risk assessment, a fire protection plan is designed that meets the specific needs of the hangar. It is common for the risk assessment to justify a wet-pipe automatic sprinkler system in lieu of a foam-based system. This plan can include a combination of suppression systems, detection systems, and operational procedures.

The Benefits of a Risk-Based Approach

When fire protection is built around the real risks in your hangar, the benefits add up quickly. Here are several advantages of using a risk-based approach.

• Cost-Effective: By tailoring fire protection to the actual risks, unnecessary expenses for equipment and maintenance can be reduced.
• Environmentally Responsible: Eliminating unnecessary foam systems reduces the potential for environmental contamination from PFAS.
• Reduced Damage Risk: Lowering the probability of accidental discharge of a foam system reduces the risk of damage to aircraft and facilities.
• Flexible and Adaptive: This approach allows fire protection systems to adapt to changes in hangar operations and aircraft.‍
• Improved Safety: By focusing on actual risks and appropriate fire protection, this approach can improve overall safety.

Why a Risk AssessmentIs Important

The risk assessment process involves a team of stakeholders who will work together to understand the risks and recommend a solution that meets the goals of the project while also adhering to the fire codes.

For example, many hangars are used primarily for aircraft storage and basic inspections, with no significant maintenance performed on site. In these cases, the risk of a fuel spill is minimal, and it may be appropriate to eliminate foam fire protection systems.

Similarly, if a hangar has a robust automatic sprinkler system or methods of early detection, then a low risk of fire spread and low consequences may also be determined, making the need for additional fire suppression beyond a water-based sprinkler system unnecessary.