The long duckbill, or beavertail, which sticks out at the rear, is to keep water from running down firemen’s necks. Originally, these helmets were sometimes worn backwards so the beavertail would protect its wearer from the intense heat of firefighting.
it’s to try to prevent neck injury from falling debris. Inside a structure the temp will reach 1300 degrees F and from personal experience, getting a shot of water down my back feels pretty darn great. Now that most helmets have a face shield some of the heat is turned away, used in conjunction with a nomex hood will turn more heat away, along with proper use of nozzles will put up a wall of water spray that will block most of the heat. good times…