This article serves as an easy guide to selecting the right manhole covers based on load class for your design requirements. We have compiled this data using the codes IS 1726 for grey cast iron and EN 124-2 for ductile iron manhole covers and grates.
Grey Cast Iron Manhole Covers and Frames Guide
In India, the Grey Cast Iron Manhole Covers and Frame have been divided into 4 categories based on their usage as per IS 1726.
- LD-2.5: The Light Duty cover is capable of withstanding 2.5MT or 25kN of load. These are suitable for use within residential or institutional complexes or areas with pedestrians as well as only occasional Light Motor Vehicle Traffic. These covers also used as ‘Inspection Covers’.
- MD-10: The Medium Duty cover is capable of withstanding 10MT or 100kN of load. They are suitable for use in service lanes, on pavements for use under medium-duty vehicular traffic including car parking areas.
- HD-20: The Heavy Duty cover is capable of withstanding 20MT or 200kN of load. They are suitable for use in institutional and commercial areas, carriageways, city trunk roads, bus terminals, with heavy-duty vehicular traffic of wheel loads between 5 to 10 tonnes, like buses, trucks and parking areas and where the manhole chambers are located in-between the pavement and the middle of the road.
- EHD-35: The Extra Heavy Duty cover is capable of withstanding 35MT or 350kN of load. They are suitable for use on carriageways in commercial, industrial and port areas, near warehouses or godowns where frequent loading and unloading of trucks are trailers are common, with slow to fast moving vehicular traffic of the types having wheel loads up to 11.5 tonnes irrespective of the location of the manhole chambers.
Ductile Iron Manhole Covers and Grates Guide
As of the date of writing this article, the Bureau of Indian Standards does not have a separate code for Ductile Iron manhole covers. As a result, the most popular code used in India is the European EN124. Manhole covers and grates up to and including a clear opening of 1000 mm are divided into 6 load classes.
- A 15: Capable of withstanding 15kN or 1.5MT of load. They are suitable for areas which can only be used by pedestrians and pedal cyclists.
- B 125: Capable of withstanding 125kN or 12.5MT of load. They are ideal for pedestrian areas and comparable areas, car parks or car parking decks.
- C 250: Capable of withstanding 250kN or 25 MT of load. The area of kerbside channels of roads which, when measured from the kerb edge, extends a maximum of 0.5 m into the carriageway and a maximum of 0.2 m into the pedestrian area.
- D 400: Capable of withstanding 400kN or 40 MT of load. The carriageways of roads (including pedestrian streets), hard shoulders and parking areas, for all types of road vehicles.
- E 600: Capable of withstanding 600kN or 60 MT of load. Areas imposing high wheel loads, e.g. docks, aircraft pavements.
- F 900: Capable of withstanding 900kN or 90 MT of load. Suitable for areas imposing particularly high wheel loads, e.g. aircraft pavements.