Midrexâs primary business is direct reduction ironmaking. We build DRI plants that work day in and day out, year after. year to provide value for our clients so that they can make. the most of their investment and maximize their profits for. years to come. The MIDREXÂ® Process 2. The MIDREXÂ® Process.
Quick Answer. The maximum interior height of an entry door threshold is 1/2 inch, and up to 3/4 inch on exterior siding doors where it is essential to keep water out, as stated by the United States Access Board. These height limits improve wheelchair access to buildings.
Most rough door openings are framed to be 6 ft., 8 in. inches high. I framed mine so it is 77-1/2 inches tall. Given the height of the rough opening and taking into account the height of the average person, I decided to design my arch to be four inches thick.