The term bottom rail is not specific to the aluminum door industry; moreover, almost all swinging and sliding doors have bottom rails and this applied to residentail and commercial doors.
The bottom rail of a aluminum storefront door is the bottommost part of the door and some refer to this as the kick plate. The size of the storefront door bottom rail is a focal point when you buy new storefront doors. Typical bottom rails are usually a little wider than the stile of the storefront door it is being installed onto. However, it is a code requirement in some states / cities to have a 10" bottom rail; moreover, this is referred to as a "10 inch ADA Bottom rail".
Before you purchase a new commercial storefront door for your shop, retail, or warehouse it is recommended that you know the limitations for your local state / city code requirements for aluminum storefront doors.
If you happen to purchase a storefront door and forget to add the 10" ADA bottom rail some aluminum suppliers offer a bottom rail extender that can be installed to your existing storefront door to convert a 3" too a 10" bottom rail.
When your purchase new doors from Storefront Doors we're familiar with most city requirements; moreover, we also provide detialed CAD design drawings that show the height of the door bottom rail for each new storefront door you purchase.
Detailed Bottom Rail Example
Detailed Image Of Storefront Door Bottomrail Usage