How much weight can a manhole cover take?

Manhole covers are manufactured in a variety of shapes – square, rectangular or circular – and sizes ranging from 300mm to 1200mm. they may be made from pressed galvanised steel, cast or ductile iron, polypropylene, composite materials and even concrete. The top surface of the manhole cover may be flush with the manhole cover frame or recessed so it can be filled with blocks, paving, asphalt, resin or grass to blend with its surroundings.

One critical factor when selecting an appropriate manhole cover is its load rating (also known as its weight class, load class or loading class), as failing to calculate this correctly can result in damage to the manhole and cover, putting vehicles and people at risk. In this blog post, we look at the regulations regarding manhole cover load ratings and how they can be used to specify manhole covers correctly for any situation.

What is a manhole cover load rating?

The correct load rating for a manhole cover will depend on the location where it is to be installed and the type of traffic that will be expected to pass over the manhole cover; this varies from pedestrian traffic (for example, a manhole cover situated in a garden or on a footpath) to ultra heavy-duty traffic such as aircraft.

To simplify the calculation process for the correct manhole cover, two classification systems have been devised: BS EN 124:2015 and FACTA. 

BS EN 124:2015 explained

BS EN 124:2015 calculates dynamic (moving) loading and is more suitable for calculating the correct manhole cover for situations where traffic may move at higher speeds. For this reason, it is more frequently used for cast or ductile iron manhole covers.

The regulations provide six load class codes ranging from A15 to F900, with the number in the code referring to the maximum load rating in kiloNewtons (kN) that the manhole cover is designed for. A number alone may be confusing, so the following list indicates typical environments in which each type may be used.

• A15 manhole covers are typically used where traffic is limited to pedestrians and bicycles
• B125 manhole covers are suitable for domestic driveways and areas where there may be occasional light traffic
• C250 manhole covers are generally installed in areas such as car parks, where traffic is limited to slow-moving cars and light commercial vehicles
• D400 manhole covers are commonly installed on main roads and similar areas that accommodate frequent, fast-moving traffic
• E600 manhole covers are designed to withstand the demands of heavy-duty industrial and commercial areas such as warehouses and docks, where traffic includes heavy plant-moving vehicles and those with solid tyres such as forklifts.
• F900 manhole covers are reserved for the most demanding environments such as airports, where traffic includes heavy commercial and military aircraft

FACTA explained

FACTA ratings are used to calculate weight classes for fabricated manhole covers, which are conventionally used in areas where traffic speeds never exceed 20 mph and vehicles are fitted with pneumatic tyres rather than solid tyres. FACTA ratings are also calculated based on kiloNewton (kN) wheel loads, as follows:

• FACTA A manhole covers are suitable for pedestrian traffic and wheel loads of up to 5kN
• FACTA AA manhole covers can be used where traffic includes small vehicles and wheeled machinery with wheel loads not exceeding 15kN
• FACTA AAA manhole covers are used in areas accessed by small to medium-sized cars with wheel loads of up to 25kN
• FACTA B manhole covers are required for areas used by heavier cars and light commercial vehicles with a wheel loading of up to 50kN
• FACTA C manhole covers should be used if medium commercial vehicles with a wheel loading of up to 65kN will be accessing the area
• FACTA D manhole covers are capable of withstanding articulated lorries with wheel loadings of up to 108kN
• FACTA E manhole covers are used in areas where heavy movers with wheel loadings of up to 158kN are being operated
• FACTA F manhole covers are installed where heavy plant or aircraft with wheel loads of up to 237kN are being manoeuvred

We hope you have found this information helpful and interesting. If you have any further questions, you are always welcome to call the friendly team of drainage experts at Drainfast on 01420 555600 or email [email protected]. 

If you are installing manholes, road gullies or inspection chambers we also recommend using MuckStopper® products to protect your drainage system, prevent blockages and keep your workers safe.

To keep informed, look out for more articles in our ongoing series of blog posts, bringing you useful information, insights, guides and tips on all things drainage!