The ergonomic fit of respiratory protective equipment (RPE) is critical for ensuring both protection and long-term usability in occupational settings. However, most respirators are designed based on outdated or foreign anthropometric data that may not represent local populations. In Chile, as in many countries without updated national databases, this mismatch can compromise comfort, effectiveness, and user compliance. This study evaluated temporal changes in facial dimensions among Chilean workers and assessed the applicability of four widely used respirator fit test panels. Two representative datasets collected a decade apart were analyzed: Dataset A (n = 474; 2013) with manual measurements, and Dataset B (n = 2016; 2024) using 3D facial scanning. Eleven facial dimensions recommended by ISO standards were examined against the LANL half- and full-facepiece panels and the NIOSH/ISO bivariate and PCA panels. Results showed significant increases in facial size, particularly among men, and a general shift toward larger facial morphologies. The NIOSH/ISO bivariate panel provided the highest coverage, while the LANL full-facepiece panel showed the poorest fit, especially among recent male participants. Gender-based differences in fit were consistent across both datasets. These findings underscore the need for updated, population-specific anthropometric references and the ergonomic redesign of respirators and fit panels. Although centered on Chile, the study has global relevance for countries that import RPE without validating fit locally. The methodology offers a scalable approach for aligning protective equipment with evolving worker characteristics, supporting international efforts to improve comfort, safety, and usability through data-informed design. These declining match rates suggest that respirator fit panels may become increasingly outdated, potentially compromising worker safety if they are not updated to reflect current population characteristics.

This study evaluates a new equation for defining maximum desk height in educational settings, comparing it with the traditional Chaffin and Anderson-based equation through biomechanical analysis. The new equation, based on 30° shoulder abduction and 35° flexion, was tested against established criteria in a quasi-experimental study involving 34 participants. Using motion capture and surface EMG, we analyzed shoulder kinematics and muscle activity during six standardized tasks performed at two desk heights. Results showed no significant differences in shoulder kinematics safety parameters between setups, while EMG data revealed consistent muscle activity patterns below 10 % MVC for both conditions. Performance metrics across tasks showed no significant differences between desk heights. Preference analysis indicated no overall significant difference between conditions, although gender-specific patterns emerged with 66 % of women preferring the proposed height. Discomfort levels were comparable between conditions. Theoretical testing of the new equation on existing databases (n: 2261 students; n: 2946 workers) demonstrated improved anthropometric fit, increasing match rates from 63 % to 94 % in students and reducing high mismatch cases from 46.7 % to 7.1 % in workers. The findings validate that the new equation maintains biomechanical safety while significantly improving anthropometric fit. This alignment between biomechanical and anthropometric criteria represents an advancement in educational furniture design, particularly relevant for contemporary educational tasks requiring forearm support.