KIO manhole cover in composite material

From June Issue of Compositi Magazine

Industrie Polieco – MPB

In 2010 Industrie Polieco-MPB, a solid European group in the sector of polyolefin compounds and high-density polyethylene corrugated pipe systems, decided to proceed with the development of a project for the construction of a manhole cover in composite material.

The composite material used for the production of the manhole cover is KinextTM, a composite material reinforced by long fibers duly distributed inside a thermosetting resin matrix. In February 2012 KIO, the manhole cover in composite material, has been presented to the market. It is produced in compliance with the EN 124:2015 standard and certified by the Italian ICMQ Institute. The smallest dimension is 300×300 mm while the largest dimension is Ø 1230 mm. Furthermore, Industrie Polieco-MPB produces 500×500 mm gully gratings in the same material, in C250 class. The resistance classes available are B125, C250 and D400.


One of the main features of manhole covers in composite material is lightness; this feature was obtained by following two ways:

  • use of materials with a specific weight lower than that of cast iron even if resistance characteristics required by the standards are always guarantee
  • study of the geometry of the manhole according to the particular production technology

In this way, cover and frame assembly weight are considerably lower than the one of other marketed products. The weight difference is more than 65% compared to manhole covers in ductile iron or grey cast iron.


The manhole cover in composite material is not subject to corrosion phenomena or attack by chemical substances: the manhole top surface is fully made of thermosetting resin, which is resistant to:

  • acid and alkaline substances
  • besides oil
  • grease
  • and hydrocarbons

The above, combined with being non-sparking and non-condensing, makes the manhole cover in composite material particularly suitable for use in fuel distribution systems. It is now common practice in countries around the world to use in such projects composite material manhole covers made instead of those in cast iron. Finally, the resistance of the thermosetting resin used in KIO to salt water should be underlined, a feature that makes the use of manhole covers in composite material particularly suitable in seaside resorts.


Cast iron systems generate noise when vehicles or people pass on them, it is due to an imperfect coupling between cover and frame or to installation errors. Thanks to the properties of the raw material in KIO composite covers, the use of a cover and a frame in composite material allows to considerably reduce the noise.


The external surface in thermosetting resin allows the manhole cover to be a perfect insulating system, eliminating the possibility of voltage dispersion and thus protecting pedestrians from the possibility of accidental electric shocks due to any exposed electrical wires. The cover is also a low conductor of heat: specific tests have shown that the insulating capacity of KIO cover in composite material is approximately 250 times higher than that of a similar cast iron cover of the same thickness; therefore KIO cover placed in contact with a heat source heats up in a much longer time than a similar one in cast iron.





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