NTL-AVIATION-AVIATION ; NTL-ENERGY AND ENVIRONMENT-ENERGY AND ENVIRONMENT ;

This report documents a study to investigate human response to the low-frequency content of aviation noise, or low-frequency noise (LFN). The study comprised field measurements and laboratory studies. The major findings were: 1. Start-of-takeoff-roll, acceleration down the runway, and thrust reversal generate high levels of LFN (below 200 Hz) at critical distances from runways (around 3000 ft in the study) which can be annoying to people living around airports. 2. Hubbard exterior sound level criteria works well as a first level assessment tool for vibration/rattle due to LFN. 3. A-weighted Sound Pressure Level (LAmax) and C-weighted Sound Pressure Level (LCmax) metrics correlate well with laboratory based subjective response to indoor aircraft noise when LFN levels are low to moderate. The same holds for rattle annoyance (again for low to moderate level LFN). Also, multiple low level LFN events may cause rattle (i.e. simultaneous multiple runway operations). 4. When high levels of LFN are present, Tokita & Nakamura thresholds with CWeighted Sound Exposure Level (LCE) metric should be used as an indicator of potential for LFN annoyance. The low-frequency noise based metrics did not perform as well as LCE. Data lower than 50 Hz is needed to assess vibration/rattle annoyance. 5. The risk of window rattle is lowered with preload and avoiding resonance response in the design. Outdoor-Indoor Transmission Class (OITC) is a better rating for rattle prone applications than Sound Transmission Class (STC) commonly used in rating windows for transmission loss.

US Transportation Collection