we will remove a door and window on the frist floor of a 2 story brick town house (built 1920.) The brick wall is an American common pattern, 2 courses of brick thick. The opening will be 6 feet and has an existing arch above. Question - are there any standards regarding the support (if any)that will have to be installed above the opening? Should 4 inch I beam or wide flange be installed or will a header of double 2x6 be sufficient or will a 6 foot arch be self supporting?