ASME/ANSI B16.9 is a standard that covers factory-made butt-welding fittings, including reducers. These reducers are used in piping systems to connect pipes of different sizes. There are two main types of reducers defined in this standard:
Concentric Reducer: The centerline of the two pipe ends is aligned. This is typically used when the pipe runs vertically and where the flow is more consistent.
Eccentric Reducer: The centerline of the two pipe ends is offset, which helps to avoid air pockets and maintains a consistent flow direction, especially in horizontal piping.