This document has been developed by the Uni-Bell PVC Pipe Association for design and installation of PVC fittings where solid-wall PVC pipe is used in non-pressure applications.The guide provides information on the wide range of fittings that are available for various dimension
ratios and outside diameters of PVC pipe through 60-inch.
https://www.uni-bell.org/Portals/0/ResourceFile/design__installation_guide_for_pvc_fittings__laterals_for_solid_wall_pvc_sewer_pipe.pdf
Clipped from: web site