One of the main features of manhole covers in composite material is their light weight. This property is achieved by following two paths:
This makes it possible to make the system consisting of cover and frame weigh considerably lower than other products found on the market.
We are given a comparison expressed in kg between the weight of the frame + cover system made of composite material and the weights of the frame + cover system made of grey cast iron and ductile cast iron by European manufacturers. The weight difference is on average beyond 70% compared to covers in grey cast iron and beyond 65% compared to covers in ductile cast iron.
| B125 | Grey Cast Iron
(kg) |
Ductile Cast Iron
(kg) |
Composite
(kg) |
| 300 x 300 | 9.00 | 8.20 | 2.00 |
| 400 x 400 | 15.00 | 12.80 | 3.10 |
| 500 x 500 | 26.00 | 18.20 | 5.90 |
| 600 x 600 | 40.00 | 29.40 | 9.00 |
| 700 x 700 | 56.00 | 38.80 | 12.90 |
| C250 | Grey Cast Iron
(kg) |
Ductile Cast Iron
(kg) |
Composite
(kg) |
| 400 x 400 | 23.00 | 25.00 | 5.50 |
| 500 x 500 | 39.00 | 33.00 | 12.00 |
| 600 x 600 | 57.00 | 45.00 | 19.40 |
| 700 x 700 | 74.00 | 61.00 | 29.80 |
The low weight considerably reduces operators’ risks during handling, installation and subsequent maintenance of the manhole covers. Law Decree 81/08 (Consolidated Act on Health and Safety at Work) defines the maximum permitted weight for handling loads on construction sites as 25 kg. The weight of composite manhole covers up to model 600×600 C250 is below this limit. Even smaller cast iron manhole covers require the intervention of two persons and the use of mechanical equipment for handling and installation.