The coating system of TML drainage pipes and fittings is based on EN 877, which says that the use of SML pipes for underground installation, which had been practiced for years, is no longer admissible. TML pipes and fittings are suitable up to soil class II, evaluation no. -5 up to -10 (as per German DVGW worksheet GW9). The superior stability of cast iron pipes and fittings plays off its advantages in the underground installation. As a reference value, a cover height of 0.8 up to 6.0 m and a simultaneous traffic load of SLW 60 can be assumed.
Watch out for the use of correct couplings for buried installation. We recommend the Rapid Inox coupling. The CE coupling, which used to be installed underground, can only be employed with an additional corrosion protection such as a tar wrapping.

On the outside, TML pipes bear a spray zinc coating with a density of at least 130 g/m² as per point 4.8.3.2 of EN 877; over that there is a brown two-components cover coat.
Inside, TML pipes receive the same fully cross-linked epoxy coating as SML pipes.