Development of a new noise helmet.
A prototype for a new noise helmet was developed because high noise levels were not sufficiently attenuated by commercially available helmets. The new helmet was designed to be tight, especially in the area of the throat and face, and to cover the entire head. The noise attenuation properties of the new helmet were tested against pink noise in an anechoic room, jet engine noise, and low-frequency noise with the test subjects wearing a miniature microphone under the protector. The new helmet provides insertion loss of over 50 dB, which is 18-29 dB more attenuation than that of the tested earmuffs in the frequency range of 1-8 kHz. It is also better (8-13 dB) than the tested earmuffs at frequencies of 125-1000 Hz, and it protects against air impurities because the air fed into the helmet is filtered.
Pääkkönen
R
R
Tampere Regional Institute of Occupational Health, Finland.
Vienamo
T
T
Järvinen
J
J
Hämäläinen
E
E
D004430:Ear Protective Devices; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D006260:Head Protective Devices; D006801:Humans; D009623:Noise, Occupational