What does the IPC require for a joint in hubless cast-iron soil pipe?
- AA hot-poured lead and oakum joint packed at every connection and caulked tight so the joint holds against head pressure during the drainage test
- A shielded coupling with an elastomeric sleeve and stainless steel clamps, tightened to the torque specified by the coupling manufacturer
- CA solvent-cemented sleeve installed over the plain pipe ends, since the sleeve spans the gap and the cement seals it without any clamping
- DA threaded coupling engaging not less than three full threads, which is the engagement accepted on threaded pipe joints
Where to look it up
https://www.charlottepipe.com/articles/cispi-310-a-guide-to-no-hub-cast-iron-connections
Why B is correct
Use the listed shielded sleeve coupling and tighten the clamps to the coupling manufacturer’s specified torque. Charlotte Pipe describes standard no-hub couplings as a gasket inside a stainless steel shield with clamps, and distinguishes medium- and heavy-duty couplings. Its standard coupling torque is 60 inch-pounds, but torque varies by product; do not apply that number to every coupling. Lead-and-oakum joints require a different hub-and-spigot arrangement, solvent cement does not join cast iron, and the plain no-hub ends are not threaded joints. Follow the applicable support requirements as well. Source: https://www.charlottepipe.com/articles/cispi-310-a-guide-to-no-hub-cast-iron-connections