The Ring-Type joint metal gaskets (also called RTJ gaskets or API joint gaskets) are heavy duty, high-pressure gaskets largely used in offshore and onshore petrochemical  industry, oil-field drilling and completion equipment, and in valves and pipework assemblies, along with some high integrity pressure vessel joints.

The right gasket material must be selected based on chemical compatibility with the media and the hardness of the flange. Generally, the gasket material should be roughly 30 Brinell less than the flange material to ensure sufficient deformation of the gasket without damaging the flange facing.

Phelps ring-joint gaskets comply with the ASME B16.20 standards, and are available for ASME B16.5, ASME B16.47 Series A, API 6B, API 6BX flanges.