Cast Iron Soil Pipe and Fittings used in the United States are classified into two major types—hub and spigot and hubless. Hubless pipe and fittings are also referred to in the plumbing industry as no-hub.
Hubless cast iron soil pipe and fittings are manufactured without a hub, in compliance with CISPI 301. The method of joining the pipe and fittings utilizes a metallic shielded hubless coupling, manufactured to CISPI 310, that telescopes over the plain ends of the pipe and fittings and is torqued to seal the joint. Hubless cast iron soil pipe and fittings are manufactured in only one class and wall thicknesses vary depending on size. There are many varied configurations of fittings and both pipe and fittings range in size from 1 1/2" to 15". Metallic shielded couplings for use in joining hubless pipe and fittings are also available in these size ranges from the member companies of the Cast Iron Soil Pipe Institute.
Hub and Spigot pipe and fittings have hubs into which the spigot (plain end) of the pipe or fitting is inserted. The joint is sealed with a thermoset elastomeric gasket or lead and oakum. Hub and Spigot pipe and fittings are available in two classes or thicknesses, classified as Service (SV) and Extra Heavy (XH). Additional wall thickness is added to the outside diameter of Extra Heavy (XH), therefore Extra Heavy (XH) and Service (SV) are not readily interchangeable. Hub and Spigot pipe and fittings are made in accordance with ASTM A-74 and are available in 2”–15" sizes. Thermoset elastomeric gaskets, lubricant, and assembly tools are available from the member companies of the Cast Iron Soil Pipe Institute.