How to properly seal a gas mask without shaving your beard face is because facial hair prevents the proper sealing of a gas mask.
The Army is in the midst of studying the effects of facial hair on protective When you look back on gas-mask training, what do you remember?.
Gas Masks and Facial Hair. This means either no facial hair or, depending upon the mask such as the MSA Advantage/M40, a "tight" goatee.
Traditional gas masks are designed to seal to your face and neck, aside, the military generally prohibits both bushy facial hair and religious.
Men with beards have a bit more trouble finding a gas mask that will seal appropriately ensuring that it seals properly without letting facial hair get in the way.