|DRYER EXHAUST DUCT FITTING TYPE||EQUIVALENT LENGTH|
|4-inch radius, mitered 45-degree elbow||2.5 feet|
|4-inch radius, mitered 90-degree elbow||5 feet|
Section M1502 Independent exhaust system. Dryer exhaust systems to be independent of all other systems and convey the moisture to the outdoors, unless listed and labeled condensing (ductless) dryers are used.
Department of Energy. Building America Solution Center. https://basc.pnnl.gov/resource-guides/proper-clothes-dryer-venting#quicktabs-guides=0