Applying Fire Protection Elements Into Aircraft Hangar Designs

Aircraft hangars are some of the most challenging structures to design when it comes to fire safety.

They’re large, open structures that house aircraft and large equipment: a combination that makes fire and smoke control difficult to manage. Aircraft hangars also house extremely flammable, combustible materials like chemical additives and jet fuel.

Needless to say, designing fire and smoke protection systems in aircraft hangars comes with a few unique challenges. But the right strategies and an understanding of local codes will ensure your building meets and exceeds expectations.

NFPA Categorizations for Hangar Fire Protection

All buildings need to adhere to certain safety codes for fire protection, and not surprisingly, aircraft hangars have much stricter guidelines than a typical structure.

Large, commercial hangars often have fire safety requirements on such a vast scale that builders often consult with specialist and fire safety engineers.

The National Fire Protection Association (NFPA) has strict standards for aircraft hangars, including NFPA 409. The NFPA 409 code standard has four different categories, based on the size of the structure:

  • Group 1 - Aircraft bay exceeds 40,000 square feet with a hangar door taller than 28 feet

  • Group 2 - Aircraft bay between 12,000 square feet and 40,000 square feet with a door shorter than 28 feet

  • Group 3 - Aircraft bay smaller than 12,000 square feet

  • Group 4 - Aircraft bay larger than Group 3, but with a membrane covered steel frame

Factors like the presence of jet fuel also affects the fire protection requirements mandated by the NFPA. For example, if you have a hangar in which only unfueled planes are stored, you may only need the addition of a sprinkler system to adhere to code.

Group 1 and Group 2 hangars are fairly similar in design requirements for hangar construction and additional fire protection systems. Basic requirements for a Group 1 or 2 hangars include:

  • Constructed of non-combustible materials

  • One-hour walls separating shops and office spaces from bays

  • Three-hour walls separating bays

  • Hangar door system must work in emergency

  • Aircraft bay columns include sprinklers systems or minimum of two-hour construction

  • Trench drains large enough to carry full flow rate of any fire suppression systems (sprinklers)

The above features are just the tip of the iceberg in terms of hangar protection. The specific codes you will need to follow can vary, so it is important to stay on top of local requirements. You can also consult with an experienced engineer for specifications for your project.

Additional Fire Protection for Hangars

In addition to proper construction and fire detection, hangars must also have active fire suppression systems in place. Three common systems include fire pumps, foam spray systems and water sprinkler systems.

Fire pumps are water pump systems connected to a reliable water source. These can provide water and suppression in a number of different ways, depending on the manufacturer's design. They may be routed to standpipes, water sprinklers, chemical suppression systems or hydrants.

Water sprinklers are a simple fire suppression tool, but one that is nearly always mandatory. Designers should consider a water sprinkler system that triggers individual spouts in the event of fire detection: this can reduce potential damage to aircraft and machinery in areas of the hangar where there isn’t a fire. Chemical or foam suppression can also be used in addition to water sprinklers.

Smoke curtains also offer an excellent solution for fire protection. Designed for draft control and vertical or horizontal deployment, smoke curtains are a useful method of barricading smoke.

These curtains deploy automatically when connected to detection systems and are ideal for closing off offices or workplaces from the rest of the hangar. By controlling smoke and air circulation, smoke curtains can help to ensure a fire is kept at bay until emergency officials arrive.

Exceed Fire Protection Expectations

Fire protection in aircraft hangars should be handled with the utmost care, ensuring that NFPA guidelines are being adhered to and custom additions like smoke curtains are considered. Know your local codes and available fire protection strategies, or consult with a qualified engineer with experience. This ensures the hangar in question doesn't just meet codes, but exceeds expectations.