In this paper, the measurement results and their special features of normalized sound transmission loss of small openings with circular aperture used for natural ventilation in facades are described. Measurements are carried out by two reverberation room method specified in the draft JIS. The effect of positions of small openings on the facades, that is in the center, near the edge or near the corner of facades, is investigated. The approximate solution of sound insulation of small openings that is located near the edge of the corner for normal incidence of sound is obtained. Here, plane longitudinal wave inside the sleeve is assumed. The approximate solution agrees fairly well with measured values of sound transmission loss in the case of the sleeve with circular aperture located near the corner for ka<1.8, where a is the radius of sleeve and k is the wavelength constant.
The International Standard 2631 that defines the measurement and evaluation method of human exposure to whole-body vibration includes the definition of frequency weightings that represent the dependency of human responses to vibration on the frequency. This paper investigates the basis for principal frequency weightings defined in the current ISO 2631 and related standards by comparing the frequency weightings and the experimental data available in the previous studies referred to in the standards. It was found that there were differences between the weightings Wk, Wg, Wb and Wz defined in different parts of ISO 2631 for the evaluation of vertical vibrations. For the frequency weighting Wk that has various applications, the experimental data that can be the basis for its definition were not clearly identified at frequencies above 10Hz, although some previous data showed agreement with the weighting at frequencies below 10Hz. The frequency weighting Wd for the evaluation of horizontal vibrations was found to be consistent with the experimental data available in the previous studies.