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Specific Area Treatments: Firewall
Not surprisingly, the firewall is most often the worst offender to the addition of noise in an aircraft. For this reason, it should be very aggressively treated for noise with dampers, barriers and absorbers.
This is a rough guide of acoustic treatments for the firewall area of a typical light aircraft. The actual results may differ from aircraft to aircraft since this by necessity must be a generalization of typical noise path and vibration common to most light aircraft. Some aircraft may be limited by space, clearances, internal volume, and contact with the pilot and passengers that therefore must be taken into account
Level 3 provides basic coverage and Level 1 offers the most insulation.
Acoustic Level 1 Treatment:
- 1. Damper on entire firewall.
- 2. 1/4" felt with 40 lb. per sq. ft. barrier in middle and more felt over dampers.
- 3. External firewall blanket.
Acoustic Level 2 Treatment:
- 1. Damper on entire firewall.
- 2. 1/8" felt with lighter weight (.20 lb per sq. ft.) barrier then more felt over damper.
Acoustic Level 3 Treatment:
- 1. Damper on entire firewall.
- 2. 1/4" closed cell foam over entire firewall.
