Why do over 80% of home renovations use 25mm male threaded tees for hot and cold water pipe branch points? It's not because manufacturers only make this size, but because it sits at the perfect intersection of pressure resistance, flow rate, and installation tolerance. Too small (20mm) and connecting two branch lines easily leads to water blockage and poor hot water circulation; too large (32mm) is wasteful of material and difficult to fit into ceilings or wall recesses.
A 25mm male threaded tee paired with a 20mm main pipe and a 16mm branch pipe requires only three and a half turns to achieve a tight seal. After heat fusion, it withstands pressure exceeding 1.6MPa, meaning it won't leak even after decades of immersion in the wall. Unlike metal fittings that corrode, and unlike PVC that softens at high temperatures, it's a crucial node that truly "silently serves" in the concealed works of modern homes.
