Impulse Assessment of the 3M(trademark) E-A-R(trademark) Skull Screws(trademark) Corded Earplug

The impulse peak insertion loss (IPIL) is the standard measure of attenuation provided by hearing protection devices (HPDs) in response to an impulsive noise. This technical memorandum describes the IPIL testing conducted and the calculated mean IPIL values for the 3M(trademark) E-A-R(trademark) Skull Screws(trademark) Corded Earplug (Skull Screws(trademark) Corded; Model: P1301). Testing was completed in accordance with the ANSI standard S12.42-2010. All device samples were tested at the nominal levels of 150, 160, and 170 decibel peak (dBP, re: 20 muPa). A total of five samples were fitted to an acoustic test fixture two times each for a total of 10 trials per test level. No samples of the HPD were rejected. The mean and standard deviation (SD) IPIL values were 48.4 (2.5) dB SPL at 150 dBP, 50.4 (2.4) dB SPL at 160 dBP, and 51.5 (2.2) dB SPL at 170 dBP. These results suggest that, when properly fit and functional, the Skull Screws(trademark) Corded will adequately protect (i.e., reduce exposure to less than 140 dBP) against impulses below 180.0 dBP.