Hub & spigot and hubless are the two main styles of cast iron soil pipe and fittings used almost around the world. In the plumbing industry, hubless pipes and fittings are known as no-hub.
In accordance with CISPI 301, hubless cast iron soil pipe and fittings are produced without a hub. A metallic shielded hubless coupling, manufactured to CISPI 310, is used to connect the pipe and fittings. It telescopes over the plain ends of the pipe and fittings and is adjusted to seal the joint. Only one class of hubless cast iron soil pipe and fittings is made, and wall thicknesses differ depending on the size. Fittings come in a variety of configurations, and pipe and fittings vary in size from 1 1/2″ to 15″.
Many companies also provide metallic shielded couplings that is used in joining hubless pipe and fittings in these size ranges. Pipe and fittings with hubs have spigots (plain ends) into which the pipe or fitting’s spigot is installed. A thermoset elastomeric gasket or lead and oakum are used to secure the joint. Service (SV) and Extra Heavy (EH) hub and spigot pipe and fittings are available in two thickness groups (XH).
Extra Heavy (XH) has an additional wall thickness applied to the outside diameter, so Extra Heavy (XH) and Service (SV) are not interchangeable. Hub and Spigot pipe and fittings are made to ASTM A-74 standards and are available in sizes ranging from 2” to 15”. The Cast Iron Soil Pipe Institute’s member companies sell Thermoset elastomeric gaskets, lubricant, and assembly equipment.