Metal concentric chimneys type WSPS Application Metal positive pressure concretic chimneys type WSPS (pipe-in-pipe) applied to carry off exhaust emissions (internal pipe) and to supply air (external pipe) to/from condensing and non-condensing fan-burner boilers with a sealed combustion chamber. Fuel Oil and gas Specification Material acid-proof steel 1.4301 Material thickness 0,5mm Working temperature ≤200 °C (gray seal); ≤120 °C (black seal) Diameter range 60/100mm, 80/125mm, 100/150mm Certificates Technical description Declaration of commercial properties