Ductile iron frames for greater strength and stability with 12.5 tonne loadings on composite covers

Arguably the most significant development in this field in the last few years. Traditionally galvanised steel frames have been used along with the plastic chambers and composite covers. This meant that although the covers were load tested to a 12.5 tonne loading the results within the frames were open to question due to the construction of the steel frame. A steel frame is manufactured by the joining of different pieces of steel welded together. A ductile iron frame is cast in one single operation and therefore there are no joins/welds. Any join is a weak spot, it therefore follows that if there are no joins then there are no weak spots. This has been proven on a test rig in accordance with the testing procedures defined in EN124 regulations. After the test was completed successfully the cover was loaded to destruction with no adverse effects on the ductile frame.