Manhole Covers & Frames Explained
Manhole Cover Size
Manhole covers come in a variety of different sizes depending on the requirements of the buildings project. Typically, manhole cover sizes will range from 300mm x 300mm to 1200mm x 1200mm and be either square, rectangular or round in shape. The size of a manhole will need to be large enough to suit the maximum pipe size and are typically at least 1 metre deep.
The size listed is usually the size of the clear opening of the manhole. For example, a manhole cover listed as 600 x 450mm will probably have a larger dimension including the frame.
What Size Manhole Cover Do I Need?
Tempting though it may be to use a cover far larger than the hole, it is best practice to source a cover that is a good size match. A manhole cover that’s too small could fall in.
What Types Of Manhole Covers Are There?
There are 3 main types of manhole cover; ductile iron, recessed/screed and solid top. Each has their own features and benefits, which we've outlined below:
Ductile iron
Solid and reliable, ductile iron will not corrode as quickly as cast iron, nor is it as brittle. Ductile iron is stronger than cast iron too. The loading classes for ductile iron manhole covers are subject to BS EN 124:2015 regulations.
Recessed/screed
These covers have recessed areas suitable for laying block paving or a layer of screed – great for decorative finishes in driveways. The loading classes for recessed covers are rated to FACTA loading specifications.
Solid top
Lighter galvanised steel manholes, often fitting flush at ground level and have inset grab handles. Usually for lighter use. Weight classes for solid top covers are subject to BS EN 124:2015 regulations.
Manhole cover weight classes
Covers subject to BS EN 124:2015 regulations are rated A15 to F900.
The numbers in the load class code denote ‘kiloNewtons’ that the cover is capable of withstanding i.e. C250 is capable of withstanding a 250kN load test.
Weight classifications for manholes are as follows:
A15
Pedestrian and cyclist use only
B125
Driveway duty and occasional light traffic such as access only routes
C250
Slow moving cars and vans such as in car parks
D400
Fast moving heavy traffic such as on main roads
E600
Heavy, moving plant and plant with solid tyres such as forklifts in heavy duty areas like warehouses, docks etc.
F900
Particularly high wheel loads such as airports
Covers rated by FACTA are listed from FACTA A to FACTA F
All FACTA wheel loads are for moving pneumatic-tyred vehicles. Please check before ordering that you have the correct load class.
FACTA A
Pedestrian use and up to 5kN wheel loads
FACTA AA
Small vehicles up to 15kN wheel loads
FACTA AAA
Cars up to 25kN wheel loads
FACTA B
Cars and vans up to 50kN wheel loads
FACTA C
Trucks up to 65kN wheel loads
FACTA D
Articulated lorries up to 108kN wheel loads
FACTA E
Heavy, moving plant up to 158kN wheel loads
FACTA F
Aircraft and heavy plant up to 237kN wheel loads
Types of manhole seals
Single seal
Most standard manhole covers have a single seal which is applied to the cover and frame. This seal can be sealant or neoprene strips. This type of seal is usually sufficient to create an airtight seal.
Double seal
This is, in effect, a doubling of the seals above, but forms a comprehensive airtight seal, so long as that seal isn’t under any pressure. This sort of seal is best suited to internal sewage manholes.
No seal
Some covers have no airtight seals but slot into place. These are often called “plain seated”. Perfect for access to cables and utilities and where smells are not going to be an issue. These types also tend to be more cost effective.
Types of locks and badges
Need your manhole locked? As an extra security measure, you have the ability to have a locking mechanism installed into the cover. Ask at the time of ordering if you need locks for your manhole covers.
What Is Manhole Badging?
Badging your manhole can be a convenient way of telling workers what’s accessible within the manhole without the need to open it. Having “gas” or “FW” (foul water) clearly visible on a manhole can save valuable time and effort in the future. If you need your manhole covers badged, please ask at the time of ordering.
