Charlotte Pipe and Foundry has added more configurations to its line of 10-inch and 12-inch PVC DWV large diameter injection-molded fittings, including new test tees. Charlotte's molded test tee fittings are very compact and fit into tight spaces. Charlotte Pipe and Foundry is the only manufacturer that offers a system of cast iron, PVC, CPVC, ABS and FlowGuard Gold® pipe and fittings for residential and commercial plumbing systems and industrial applications.Charlotte Pipe and Foundry.