The effect of hair and beard on the airtightness of gas masks

This study aims to quantitatively analyze the correlation between hair and beard and the airtightness of gas masks in response to the escalating threat of chemical and biological warfare, changes in military personnel regulations, and grooming standards. Airtightness refers to the ability of a gas mask to fit snugly on the user face, thereby preventing the infiltration of harmful external substances, that is among the primary functions of the mask. Although hair and beard are known to affect the airtightness of gas masks, research is lacking in this area, domestically and internationally, and no studies have analyzed the correlation between gas mask airtightness and hair, including beards, under controlled variables. Therefore, research on the correlation between gas mask airtightness and hair, including beards, is necessary to respond to the current evolving threats. For this purpose, gas masks that passed the airtightness performance test specified in military standards were selected. The masks were fitted on a SMARTMAN (SiMulant Agent Resistant Test MANikin) mannequin head with artificial hair and beard attached, and changes in airtightness were measured based on the presence and condition of the hair and beard. The experimental results showed that the presence of hair and beard at the gas mask–face contact surface decreased the airtightness of the mask, and that the highest airtightness was observed with gas masks of the optimal size. The findings of this study can be used as an important reference material for maintaining the performance of gas masks and the combat effectiveness of the military.