A 150mm twin wall 135° tee is a specialized fitting used in twin wall flue systems, specifically when the flue needs to change direction at a 135-degree angle while providing access for sweeping and inspection. It's designed to connect the flue pipe to a wall, typically at a 45-degree angle, and then continue vertically.
Twin-wall flues are designed with two layers of stainless steel, providing insulation between the flue gases and the surrounding environment. This design helps prevent condensation and ensures proper flue performance, even in condensing applications.