About copolymer manhole
Polymer is large molecules that are made from attaching many numbers of small and simple molecules named monomers. If monomers of a polymer are made of one type, they are called homopolymer, some of them include polystyrene, polypropylene, polyethylene, and PVC. If monomers of polymerization reaction are made from two or several different types, the obtained polymer is called a copolymer.
Copolymers are used to build manholes in addition to using some materials such as cast iron, concrete, composite, Nano-composite, polyethylene. Copolymers are being used increasingly in different industries as an appropriate replacement for cast iron and concrete manholes because of having some properties such as relatively lower cost, being anti-theft, appropriate weight, easier transportation. Copolymer manholes are built-in circular, square, and rectangular shapes in different dimensions depending on the place where it is being used, required properties from the manhole, and also the costumer’s order.
According to the new standard, these manholes can be produced in non-traffic form. Therefore, copolymer manholes with a strength level of A15 are used in pedestrian passages, bicycle tracks, parks, and playgrounds as the covering lid over manholes and are sold more than other types for these purposes.
The weight and price of copolymer manholes
It can be said that the most standing property of copolymer manholes is their very low weight compared to other types of manholes available in the market. In other words, if we consider all influential parameters on the weight of a manhole as a constant value, parameters such as shape, dimension, and bearing capacity, copolymer manholes are the ones in the market with the lowest weight. The lower weight of copolymer manholes is a strong point and also a weak point for them. In other words, the lower weight of these manholes cause easier transportation and installation procedures for them and decrease the transportation and installation expenses greatly. Because one person can solely carry or open and close it without danger. On other hand, the lower weight causes that copolymer manholes to make noise due to the passing of vehicles if no lock and stabilizing equipment is used in their structure, and get displaced due to surface water pressure in severe rains or get displaced when high-speed vehicles pass over them. Other properties of these manholes are their anti-theft property, having the capability of being produced in different colors. But, they are very weak against the sunlight and they break into a brittle state under sunlight. Also, they cannot be detected by metal detectors because of no used metal in them.
Copolymer manhole standards
The European standard of EN124 is the main standard in the production of copolymer manholes. In addition to that following standards are used in the manufacturing of this type of manhole.
ASTM D1501 resistance against sunlight
ASTM D543 chemical resistance
ASTM D570 water absorption rate
ASTM D635 resistance against flame
