12.7mm thick blue ground protection boards 60 T load capacity Oct 05, 2017 · For example, a pipe that has an outer diameter of 60.3 mm and a wall thickness of 2.8, has an internal diameter of 60.3 – (2.8 x 2) = 54.7 mm. Green rresponds to extra light thickness, yellow rresponds to light thickness, blue to medium, red to heavy, and white to