Measurement of insertion loss of ear-muff type protectors using the impulse response technique

The essential requirements that hearing protectors need to fulfil as personal protective equipment are evaluated in Argentina through a series of IRAM (Instituto Argentino de Normalización y Certificación) standards. In particular, IRAM 4060-3 (equivalent to ISO 48693:2007) standard specifies a simplified method for the measurement of insertion loss (IL) of earmuff type protectors. This method can be used to test occasional performance differences on manufacturing, as part of type approval or certification procedures, and to investigate performance variations due to product aging. The IL of a hearing protector is commonly obtained using systems based on broadband pink noise (BPN) signals. This paper analyzes and compares the IL of eight different hearing protectors obtained with this technique and with an impulse response measurement based system. The results show that both techniques present similar IL values, within the dispersion range expected for this test. Also, the impulse response system reduces the test execution time, and proved to be robust, reliable and economical.