This app will provide SMACNA compliant options for rectangular duct with dimensions from 1 inch to 120 inches for applications from negative to positive ten inch water gage. The scenarios for the app are limited to joint lengths of 4, 5, and 6 feet. The transverse connections are limited to T1 (flat drive), T5 (flat slip), T10, 11, and 12 (standing slips) and T25 a or b (TDC/TDF). Where appropriate the app will also provide options for intermediate reinforcement. The full range of reinforcement spacing options is 6, 5, 4, 3, 2 ½, and 2 feet. In most cases the app will provide options for internal reinforcements and external reinforcements. Internal options are limited to EMT conduit tie rods and external reinforcements are limited to angles. Enough information is provided so users can choose other options from SMACNA’s Standard. The output of the app is a written description of the duct as well as a graphic representation. Users can view the report on-screen or email it. The app does not provide every possible solution found in SMACNA’s standard and it will not provide every detail. For example, the app does not provide requirements for the proper attachment of the reinforcements. The app is intended to be used in conjunction with SMACNA’s HVAC Duct Construction Standard.