If you are looking to restrict access to an underground inspection chamber/plastic manhole chamber or drainage system, or you simply want to prevent debris, soil, and other items from falling into it, then it is important that you select the right type of cover. In addition to providing adequate coverage, a removable lid must also comply with UK health and safety regulations and be manufactured to a high enough standard to ensure that it is fit for purpose.
In this online guide, we aim to help you make the right choice by highlighting the differences between manhole covers, access covers and gully grates so that you can easily identify drainage covers and determine which type you need for the site or area you need to protect.
Manhole covers – which are also sometimes referred to as maintenance hole covers – are protective lids that are installed at the entry points of underground inspection chambers, such as foul and surface water drainage systems. They are designed to prevent people, animals or items from falling into the chambers, and to ensure that only authorised people are able to access them – this means that they are large enough to enable a person to pass through, while also often being intentionally heavy and difficult to remove.
Due to the intended purpose of a manhole cover, they are usually manufactured from extremely strong and durable materials including galvanised steel and cast iron. This means that they can only be removed using certain tools, and they can withstand being regularly driven over by varied weights of traffic. In heavy duty areas where an extremely high load bearing capacity is required, such as airport runways, manhole covers can also sometimes be produced using ductile iron which offers excellent wear and impact resistance. Some covers are also produced using heavy duty polypropylene, which is a thermoplastic used across many applications, and is both hard-wearing and highly durable.
Manhole covers are available in circular, square, rectangular, and triangular shapes, as well as a wide range of sizes to suit various applications and environments. Usually located outside rather than inside (although not always) some also feature a manufacturer’s logo and specific markings to enable trade workers and professionals to more easily identify manhole covers and the services that they provide access to.
They are also available with varied load ratings that comply with the BS EN 124:2015 standard for gully tops and manhole tops for vehicular and pedestrian areas. These ratings include:
A15 Load Rating (5 Tonnes): Suitable for areas used by pedestrians and pedal cyclists only
B125 Load Rating (12.5 Tonnes): Suitable for footways, pedestrian areas, car parks and car parking decks
C250 Load Rating (25 Tonnes): Suitable for gully gratings fitted in the kerbside channels of roads
D400 Load Rating (40 Tonnes): Suitable for covers and gratings installed in road carriageways, hard shoulders and parking areas (for all types of vehicles)
E600 Load Rating (60 Tonnes): Suitable for areas with very high wheel loads such as aircraft pavements and loading docks
F900 Load Rating (90 Tonnes): As with the E600 rating, this rating is suitable for areas with very high wheel loads such as aircraft pavements and docks but can handle a higher weight
Installing a manhole cover is a relatively easy process, however it requires a level of experience in using fast-set mortars designed for bedding in ironwork. It involves carefully removing an old frame as well as the cover, and any surrounding material that was used to embed it (which is usually either concrete or tarmac). Once the area has been properly cleared, you can then level it out before bedding in the new cover frame, backfilling around the frame, and then finally placing the cover in its correct position. You should note that any type of cover must be installed along with the frame that it has been manufactured with, so if you need to repair a broken cover, you must replace the entire unit – replacing just the cover itself could lead to safety issues by compromising the structural integrity of the solution, which is especially dangerous in any area where either vehicles or people are likely to travel across the cover. Drain cover failure can also occur when a cover has an insufficient load class for its application, or when the incorrect bedding mortar is used during installation, so always check that the product you are using is suitable for use on ironwork conforming to the BS EN 124 standard.
Access covers are essentially very similar to manhole covers as they are also used to protect openings to specific underground utilities and prevent unauthorised access. Located either inside or outside of buildings, access covers can often be found within pavements, driveways, gardens, car parks and footpaths, and are usually installed to conceal access points for electrical wiring and cabling, as well as plumbing, draining, ventilation or heating systems.
As access covers are more likely to be positioned near to property in pedestrian and landscaped areas, they are usually manufactured from lighter materials than manhole covers, such as aluminium, steel or a composite of both. This not only provides adequate load bearing for most applications, but also offers an improved aesthetic which is particularly preferable when they are being installed in locations near or within domestic properties such as a garden or a driveway. Recessed access covers are also available, which are designed to be filled with materials such as granite, tiles and bricks to help them blend in with their surroundings while also providing a concealed access point for necessary maintenance.
Generally, access covers are available in square or rectangular shapes and, as with covers for manholes, they also come in a wide selection of sizes. They can also be fitted with lifting keys or hinges that provide easier access where required.
Where access covers are to be installed in heavy duty areas, they must also be manufactured in line with the BS EN 124:2015 standard, however for areas with much lighter load bearing requirements, they can be produced in line with classifications that are outlined by the Fabricated Access Covers Trade Association (FACTA). The ratings range between FACTA A through to FACTA F, and cover load bearings up to 237kN.
The method used to install ground access covers may vary slightly depending on the location, style of cover and manufacturer, however in general the process is the same as when installing a manhole cover. This involves levelling out the relevant area, bedding in the cover frame and backfilling around it, and then finally placing the cover in its correct position following the specific fitting instructions of the manufacturer.
Gully gratings are used to stop large objects, debris, people and animals from entering a drainage system, while also enabling rainwater from the sides of roads and highways to be collected to prevent flooding. They can also stop leaves and twigs from falling into pipework which can cause problems such as underground drainage blockages.
Positioned on top of a road gully, gully grates collect surface water from roads and enable it to be directed into a watercourse, storm drain or a soakaway crates system. Alternatively, they can also be positioned on top of yard gullies which are similar in design but usually much more lightweight as they are not required to withstand the weight of vehicular traffic.
Gully grates – which are sometimes referred to as gully grids – are covered by the same European standard as manhole covers, and come in various sizes with different load bearing capacities, so they can be used for a wide number of applications. Gully grates are also usually rectangular, square, or circular, with visible slats to enable channel drainage and surface drainage, and are often produced using cast iron or aluminium. Some models also feature captive hinges to reduce theft, and gully grates are extremely easy to fit as most can simply be dropped into place on top of a gully as required, however if you are unsure on the process you should appoint drainage professionals. You can read more about gully drains in our previously published buyer’s guide.
While gully grates are only suitable to cover drains and are therefore easier to identify, manhole covers and access covers can be visually much more similar as both are essentially removable lids, so to determine the type you need to invest in for a specific application, you should consider the following:
Loading Specifications: Above all, you must ensure that the cover you select offers adequate load bearing for the weight and speed of traffic that is likely to be travelling over it. This can vary from pedestrian areas with light footfall, to incredibly heavy duty areas such as shipping docks. If you are unsure, we recommend that you check with manufacturers or get in touch with the EasyMerchant Customer Service team, and if choosing between two covers, we would advise that you opt for the model with the higher specification to err on the side of caution.
Safety and Security: As well as ensuring that the cover you install is appropriate for its intended environment in terms of load bearing capacity, you might also need to consider how easy – or how difficult – it should be to access the chamber it is being used to conceal. Some covers feature locks to improve site and location security, while others can be fitted with tamper-proof screws to restrict access to those only with specific tools and equipment.
Unfortunately, some manhole covers – particularly a ductile iron manhole cover – can also be a target for theft in certain areas due to the high monetary value of the volume of metal that is used to produce them. Where this is likely to be an issue in terms of both the expense incurred and the compromised safety of vehicles and people, some installers prefer to opt for drain covers that have been manufactured from composite materials rather than heavy metals as they have no scrap metal value and are therefore very unlikely to be stolen.
Manufacturing Standards: You must always ensure that the covers you use in vehicular or pedestrian areas comply with relevant manufacturing standards, and that they also feature either the British Kitemark or a comparable third-party accreditation to denote their quality and durability. You can find more information about the BS EN 124: 2015 classification on the BSI website.
Sizing: There are many cover sizes and thicknesses available, however the size of the cover you will need of course depends on the size of the opening into the chamber, the gully, or the access of a drawpit (which is a type of chamber that is situated along a line of underground ducting). When you are taking measurements for a replacement manhole cover or access cover, you should avoid measuring the cover itself – instead measure the internal sides of the chamber shaft or opening as this is the standard approach to getting the right size. Where a new manhole opening is being installed, the standard opening size is now usually 675cm x 675cm.
Commercial Grade Covers
At EasyMerchant we stock various sizes of manhole covers and access covers made from a wide range of materials, as well as a selection of high quality gully grids. All of our products are manufactured by leading brands such as Brett Martin and Eccles, and they meet the required European production standards to give you peace of mind. Many of the products and accessories available via our online store also carry the Kitemark stamp to signify approval from the British Standards Institution.
In addition to supplying commercial grade products, our Customer Service team is also on hand to offer expert guidance and information where needed. If you need further advice on which of our drain cover products you should use to protect your underground utilities or sewer drains, or if you have any installation questions, please do not hesitate to get in touch.