Manholes are an important construction element that offers a number of functions. They allow maintenance workers to access the underground piping and the telecom lines that have been laid out under the roads. Moreover, they are also an access- point for meters that measure the flow of liquid in the sewer lines. These manholes however, need to be covered so that a pedestrian crossing the road or walking on the sidewalk might not fall into it accidentally. These manhole covers are also necessary because they help the cars to run smoothly on the roads without having the fear colorful chair covers that their tires might get stuck in.
Types of Manhole Covers
These covers come in various designs and materials, each offering a different set of features and advantages. Besides the dimension of the cover, the material that has been used in its making is of prime importance. It is the material of the cover that determines how much load the cover can bear and whether it can stand the test of time. Nowadays, the “composite material covers” have gained immense popularity because of their high load ability and a higher life span than the traditional “cast iron covers”. There are three types of composite manhole covers available in the market at the present time.
BMC Manhole Covers
BMC or Bulk Molding Compound is a type of composite material used for manufacturing BMC covers. The elements that are used in the making of these covers include unsaturated polyester resins, glass fiber, calcium carbonate, trasys and steel bars. The method of production of these types of covers is very simple and does not cost much as well. The advantage of BMC covers is that they have a smooth surface and a uniform color akin to plastic. However, the load ability of these covers is on the lower side and they are also susceptible to friction.
SMC Manhole Covers
SMC or Sheet Molding Compound is another type of composite material that is used for the synthesis of SMC covers. The elements that are utilized in the making of these covers include unsaturated polyester resins, glass fiber, calcium carbonate, trasys and a small amount of an additive. The method of production of SMC covers is a little complex than that of BMC covers and is costly as well. SMC covers has smooth surfaces and have a better load ability than BMC covers. However, just like BMC covers,they are also susceptible to friction.
FRP or GRP Manhole Covers
FRP or Fiber Reinforced Plastic is the best composite material used for making manhole covers. It has elements like unsaturated polyester resin, glass fiber, quartz and two different types of additives. The method of manufacturing them is quite complex as compared to BMC or SMC covers. The FRP manhole covers have a good surface, are wear-resistant, and have extremely high load ability. Because of these reasons, those that are made using FRP composite material have a much longer lifespan than BMC and SMC.
If you are interested in buying manhole covers then browse the internet resource. You are going to find the best plastic manhole covers products at reasonable prices.