BS EN 124:2015 Loading Classes Explained A15 to F900
If you’re specifying manhole covers, access covers or gully gratings, you’ll see loading classes everywhere: A15, B125, C250, D400, E600, F900. This guide explains what they mean, how to choose the right one, and the common mistakes that lead to failed covers and costly replacements.
What is BS EN 124?
BS EN 124 is the European standard for gully tops and manhole tops used in vehicular and pedestrian areas. It defines six loading classes based on a test load applied during certification. Helpfully, the class number tells you the test load: a D400 cover is tested to 400 kilonewtons (around 40 tonnes), an F900 to 900 kN (around 90 tonnes).
The current version, BS EN 124-2:2015, covers ductile and grey iron products. Genuine compliance means independent third-party testing — look for certification such as the BSI Kitemark rather than a manufacturer’s self-declaration. All R&B ductile iron manhole covers and gully tops carry BSI Kitemark KM 789143.
We go beyond the standard. Every Kitemarked R&B product is load tested to 10% above the BS EN 124 requirement for its class — so a D400 cover isn’t just tested to 400 kN, it’s proven at 440 kN. That built-in margin means confidence that our covers perform in the real world, not just in the test lab.
The Six Loading Classes
| Class | Test load | Typical applications |
|---|---|---|
| A15 | 15 kN / 1.5 t | Pedestrian and cycle areas only — gardens, footways closed to vehicles. Never use where a vehicle could mount the cover, even occasionally. |
| B125 | 125 kN / 12.5 t | Footpaths, pedestrian precincts and car parks accessed by cars and light vans. The workhorse class for domestic driveways. |
| C250 | 250 kN / 25 t | Kerbside channels and slow-moving traffic: car parks, forecourts, industrial yards. Covers within 0.5 m of the kerb line typically require C250 as a minimum. |
| D400 | 400 kN / 40 t | Carriageways (including pedestrianised streets permitting deliveries), hard shoulders and parking areas for all road vehicles. The default for adopted highways. |
| E600 | 600 kN / 60 t | Docks, warehouses, distribution yards and heavy industrial areas with forklift and heavy plant movements. |
| F900 | 900 kN / 90 t | Airport pavements, ports and areas subject to extreme wheel loads. |
How to Choose the Right Class
- Identify the worst-case vehicle that could ever cross the cover — not the typical one. A grass verge that a refuse lorry occasionally mounts needs more than A15.
- Check adoption requirements. Covers on adopted highways must generally meet D400; local highway authorities and Sewers for Adoption / Design and Construction Guidance set specific requirements.
- Consider location within the road. Kerbside and channel positions, cycleways and hard shoulders each have minimum class conventions — our team can advise on specific cases.
- Don’t forget the frame and bedding. Most in-service failures are installation failures, not cover failures. Follow the manufacturer’s installation instructions (ours are in our Downloads library).
- Think about handling and safety. For large or heavy covers, options such as torsion spring assistance allow safe one-person operation.
Common Specification Mistakes
- Under-specifying kerbside gullies — gully gratings at the channel line take repeated wheel impacts; C250 minimum, D400 where traffic runs over them.
- Using clear opening size alone — two covers with the same opening can have very different frames, depths and seating designs, even within the same loading class.
- Assuming all “D400” covers are equal — uncertified imports marked with a loading class may never have been independently tested. Ask for the Kitemark certificate.
- Ignoring skid resistance — on highways, consider skid-resistant treatment, available across R&B’s entire ductile iron range.
Grey Iron vs Ductile Iron
Grey iron suits the lightest loading classes — A15 applications — and remains fully certified for that use. Ductile iron offers a far higher strength-to-weight ratio, making covers easier to handle on site while performing in the toughest environments — which is why B125 through F900 loading classes are ductile iron.
Frequently Asked Questions
What does D400 mean on a manhole cover?
It means the cover has been tested to a 400 kN load (around 40 tonnes) under BS EN 124, making it suitable for carriageways and all road vehicles.
Can I use a B125 cover on my driveway?
Yes — B125 is designed for car parks and areas accessed by cars and light vans, which covers domestic driveways.
What loading class do I need for a road?
Adopted carriageways generally require D400 as a minimum. Docks and heavy industrial areas step up to E600, and airports and ports to F900.
Is BS EN 124 a legal requirement?
It’s the recognised standard required by highway authorities, water companies and most specifications in the UK. Independently certified products (e.g. BSI Kitemark) provide the evidence of compliance that adoption processes demand.
How are R&B covers tested?
All our Kitemarked products are independently certified under BSI Kitemark KM 789143 and load tested to 10% above the BS EN 124 requirement for their class — for example, our F900 covers are proven at 990 kN rather than the standard 900 kN.
Need Help Specifying?
R&B UK manufactures and supplies BSI Kitemark certified ductile iron manhole covers and gully gratings across every loading class — each one load tested to 10% above the BS EN 124 requirement — with standard sizes ex-stock in Telford for nationwide delivery. Call +44 (0)1952 580 554 or get in touch — we’ll help you specify the right cover first time.