Use of actimeters to determine awakenings by sounds of large guns

The U.S. Army has been using the day-night average sound level (DNL) to manage the community noise impact from heavy weapons noise since the late 1970’s. In this case, the DNL is C-weighted as recommended by the National Academy of Sciences-National Research Council Committee on Hearing, Bioacoustics and Biomechanics (CHABA). CHABA’s recommendation was justified by the fact that C-weighting (originally developed for the loudness of intense sounds) measures lower frequency sound energy in large guns which is otherwise missed by A-weighting. When the CHABA methodology was first adopted, there was relatively little night firing, but, today, night vision technology makes firing during darkness an absolute necessity for military readiness. Recognizing that the 10-dB penalty incorporated in the DNL methodology was not intended to predict sleep disturbance and that sleep disturbance may be a function of discrete noise event levels rather than annual-average noise levels, the U.S. Army Engineer Research and Development Center initiated a project to measure sleep disturbance among people living near tank gunnery ranges. A first step in this project was to evaluate whether a commonly-used instrument for measuring sleep disturbance, the actimeter, would be sensitive to awakenings from blast noise. After preliminary screening of three designs of actimeter, the preferred design was tested in cooperation with the Army Center for Health Promotion and Preventive Medicine with subjects sleeping inside the Army Research Laboratory’s Hostile Environment Simulator. Subjects were exposed to nighttime blasts at two linear peak sound pressure levels (110 dB and 120 dB). The results confirmed that the preferred design would be a reliable and rugged instrument for the actual field study of awakening from live fire. This article is a government work and as such, is in the public domain and not subject to copyright.