What is the key characteristic of a no-hub cast iron installation?

The key characteristic of a no-hub cast iron installation is the use of specific torque settings for the collars that join sections of pipe. This system relies on the design of the no-hub fittings, which allow for connections without the need for additional adhesive materials like glue or welding. The fittings typically involve a rubber gasket and a clamp that secures the joint. The specific torque settings ensure that the joint is tight enough to prevent leaks while also preventing damage to the gasket and fitting. Proper torque application is critical as it provides the necessary compression of the gasket to form a reliable seal, ensuring the integrity and performance of the plumbing system.

While tightening bolts is a part of the installation process, it is the adherence to specific torque settings that is crucial for the effectiveness of no-hub installations. Flexible fittings and welded joints do not characterize no-hub installations in the same way, as no-hub systems are designed to be rigid yet accessible for maintenance and adjustments.