Guide to Manhole Cover Selection

Types of Manholes

The kind of manhole cover is dependent on the depth of the manhole. Depending upon the depth the manhole can be classified as：shallow, normal, and deep manholes.

Shallow manhole provided at shallow depth of 75-90cm (2′-3′). Shallow manholes are used at the points which are not subjected to heavy traffics. They are also known as the inspection chambers.

Normal manhole is the one that can bear a certain amount of traffic and are usually square and rectangular in shape. It is provided in sewer line at depth of 150cm with a heavy cover on its top.

Deep manhole is used at the point which is subjected to heavy traffic. They are provided at depth greater than 150cm with heavy cover at the top. They are large in size, and a facility for going down is provided along with the deep manholes.

Therefore, there are corresponding norms and standards for manhole covers used in different environments-BS EN124.

Weight Class for Manhole Covers

A15 = Pedestrian and cyclist Utility

B125 = Occasional light traffic and driveway duty

C250 = Slow movement of cars and vans( For example in car parks)

D400 = Main road traffic-fast moving traffic

E600 = Heavy duty traffic like in warehouses, docks, etc. Movement with solid heavy tyres

E900 = For areas with heavy duty loads eg. In airports

Based on its class, we can distinguish manhole covers into three types, light manhole cover, medium-duty manhole covers, and heavy-duty manhole covers. 

Material of Manhole Covers

Based on its material, manhole covers can be divided into cast iron manhole covers, ductile iron manhole cover, cement manhole covers, and composite manhole covers. Some people call composite manhole covers a plastic manhole cover, but composite manhole covers have superior performance far surpassing plastic manhole covers. Composite manhole covers also include many types, including SMC manhole covers, BMC manhole covers, FRP manhole covers and so on.

Other Details and Points

In order to better integrate into the environment, an embedded manhole cover can be selected for use in places where paving, paving or filling is required. Only a few millimeters of the frame are still visible. lf it is still less secure, you can add the lock as additionalsecurity.

It is necessary to provide safer protective measures and increase the hinged hinged manhole cover. Opening is easier and safer.

Used in hotel projects, select airtight manhole covers to prevent gas from escaping. 

Selection of manhole cover size

It is often thought that the size of a manhole cover should be measured by its outside dimensions, but is wrong. Manhole covers are manufactured and sold by their clear opening size(the size of the manhole that’s being covered) and not the size of the cover itself. 

This is so the cover can sit securely over the top of the manhole. It doesn’t matter if the cover is square or round.

It is always advisable to employ a manhole cover that exactly fix the manhole or greater size. A smaller size could fall in.