| Popis: |
Tracked‐vehicle crewmembers operate in an acoustical environment that is one of the most inhospitable encountered in the U.S. Army. Overall noise levels in the M1A2 Abrams tank and M2A2 Bradley Fighting Vehicle can be well over 100 dBA and can exceed 130 dB in some octave bands. Due to the nature of the crewmembers’ duties, speech communication is essential for effective operations and this capability is seriously degraded because of the nature of the noise environment. The Communications Earplug (CEP), consisting of miniature receivers attached to replaceable foam earplugs, is used in Army aviation to provide superior noise attenuation with improved speech communication. The noise attenuation of the DH‐132A Combat Vehicle Crewmans helmet (CVC) when used in conjunction with CEP (measured in accordance with ANSI S12.6‐1997) is reported with an NRR of 27 dB vs 15 dB for the CVC alone. CEPs were installed in the helmets of 77 tracked‐vehicle crewmembers. Following a 6‐month trial period, crewmembers (n=36) reported increased noise attenuation, improved speech communication, and reduced stress when using the CVC‐CEP integration. The CEP is a cost‐effective alternative to expensive active noise reduction helmets currently being fielded for use by tracked‐vehicle crews. [Work supported in part by USACHPPM.] |
