Standard Manhole Base Configuration and Terminology

Left turns, right turns, and degrees of angle are determined from the down stream perspective, that is, if you were to imagine the pipeline as a river and you are in a boat going down stream, you would be imagining the proper position from which to determine whether a turn is to the right or to the left. The number of degrees that your boat would change direction would be equal to the angel of the turn, either 45 degrees or 90 degrees for a standard base.