What factors do you take into account when choosing a suitable manhole cover? Read on for more information.
Many manholes cover come in standard sizes, which are generally measured in millimeters (mm). However, bespoke options are also available on request.
Solid top covers when installed in the chamber opening will remain fully visible once installed.
Recessed covers have a recessed area for filling with block paving, slate or tiles, etc. to disguise the cover. When installed you should only be able to see the lifting points and the edges of the frame and tray. They are often used in domestic parking areas, gardens and swimming pools, etc.
It is important to know the weight load required for your application to ensure that you choose a correctly specified manhole cover.
In order to find out the weight load, you need to consider what traffic will pass over your manhole cover. Exceeding the maximum weight load of a manhole cover will significantly reduce its service life and may lead to possible safety issues.
Each material has its own advantages and is suitable for different scenarios, both aesthetic and environmental types. It includes galvanized steel, stainless steel, ductile iron, aluminum, polypropylene, etc.
Galvanized steel and stainless steel
Galvanized steel manhole cover refers to its zinc coating. It acts as a protective layer to combat the rust caused by moisture and oxygen. Stainless steel manhole covers, on the other hand, are an alloy made of a combination of iron, carbon, and chromium (sometimes including other elements), which provides significant resistance to corrosion.
Cast iron manhole cover is an alloy made mainly of iron, combined with some carbon and silicon. It is resistant to high temperatures; it is strong and copes well with strong vibrations. However, cast iron is not very ductile, which increases the risk of cracking.
Galvanized steel manhole covers are more susceptible to high levels of acidity and saltwater, which can affect the sustainability of the cover. Stainless steel is therefore essential to avoid rusting in swimming pools or where chlorinated water is present, near the sea, or in areas of acid rain.
Polypropylene
Fully polypropylene manhole covers feature a unique non-slip surface with a tread pattern; are durable; and are lighter compared to ductile cast iron.
Ductile and cast iron
A ductile iron manhole cover is an alloy made from nodular graphite. Its advantages include excellent ductility so it will not break when bent; slightly lower temperature limits than cast iron, but still retains high strength and durability, especially in premium ductile iron.
Aluminum
Aluminum manhole covers are very light and have a highly aesthetic extruded structure. Despite its high quality, it is more cost-effective than stainless steel.
Indoor or outdoor manhole covers may have different requirements, such as sealing and the ability to prevent odors.
Grass-top manhole covers are recessed covers with pre-drilled drainage holes and a factory-installed double layer of specialist membrane, as grass can grow in the recessed tray while the water is gradually filtered out. It would be unsightly to have manhole covers on the lawn.
Having a proper well cover ensures that the cover performs as expected. Well, covers are first listed by their clear opening size. This is because the most important part is to ensure that the drainage opening is accessible and matches the size of the existing well chamber.
Find out the depth of mortar, tiles, or slabs that you want to fill the recessed cover with. If you decide to go with a recessed cover, then you need to find out the right depth for your project.
We are a manhole cover manufacture, please feel free to contact us if you need them.
