That means that if ABS and PVC are connected together, some type of adapter or fitting needs to be used. That's it, that's all that's allowed. The image below shows one such adapter on the right side.

Plastics News is showing changes in pricing for PVC, solid polystyrene, polycarbonate, nylons 6 and 6/6, and ABS resins. Low demand sent North American prices for PVC and solid polystyrene resins down ...

Formula 40 announces a new process for recoloring vinyl, leather, ABS and PVC plastic, and fiberglass gelcoats. This process is a polymer resin that permanently bonds to the material without changing ...