Description
The 900x900x100mm D400 Highways ductile iron manhole cover (MDD9090DT10) is a large-format heavy-duty access cover specifically designed for highway use and areas of heavy traffic. Rated D400 to BS EN124:2015, Kitemarked and stated by the manufacturer as CD534/HA104 compliant, it provides a highway-specification solution where a larger square chamber opening is required.
Featuring a 900 × 900mm clear opening, 1050 × 1050mm overall frame size and 100mm frame depth, the MDD9090DT10 provides generous access to larger underground chambers while retaining the heavy-duty specification required for trafficked environments.
The cover incorporates a double triangular lift-out configuration and is specified as compatible with all mainstream D400 composite chamber systems. This makes it particularly suitable for highway utility chambers, cable chambers, communications infrastructure and other large service access points situated within areas subject to regular vehicle traffic.
A Common 900×900 D400 Manhole Cover Size
900 × 900mm is a commonly specified large manhole cover size, used across utility, commercial and civil engineering projects. The MDD9090DT10 is suitable for both new installations and replacement projects where a 900 × 900mm clear opening and highway-grade D400 specification are required.
For replacement projects, always check the overall frame dimensions and frame depth as well as the clear opening. Different manufacturers can use different frame footprints even where products share the same nominal 900 × 900mm opening. This particular product has a 1050 × 1050mm over-frame size and 100mm depth, and the manufacturer specifically notes that tread pattern and over-frame dimensions may vary.
Suitable for highways, carriageways, utility chambers, cable chambers, telecommunications infrastructure, composite chamber systems and other heavily trafficked civil engineering applications, the MDD9090DT10 provides a large-access highway solution where a 100mm deep frame is specified.
Looking for other options? Browse our full range of D400 Highways Manhole Covers or explore our 900×900 Manhole Covers to compare alternative load classes, manufacturers, frame depths and specifications.
Need a deeper frame? View our 900x900x150mm D400 Highways Manhole Cover (MDD9090DT15) for the equivalent highway-specification cover with a 150mm frame depth.
Key Features
- D400 heavy-duty load classification
- Designed for highway use and areas of heavy traffic
- 900 × 900mm clear opening
- 1050 × 1050mm overall frame size
- 100mm frame depth
- Large-format square access opening
- Double triangular lift-out configuration
- BS EN124:2015 Kitemarked
- CD534/HA104 compliant
- Compatible with mainstream D400 composite chamber systems
- Suitable for new installations and replacement projects
- Bespoke badging available, including FW/SW
- Optional sealing plate available
- 150mm deep-frame alternative – MDD9090DT15
Typical Applications
- Highways
- Carriageways
- Areas of heavy traffic
- Highway utility chambers
- Large utility chambers
- Cable chambers and cable pits
- Telecommunications chambers
- Communications infrastructure
- Composite chamber systems
- Highway drainage infrastructure
- Commercial developments
- Industrial infrastructure
- Civil engineering projects
- New highway installations
- Replacement 900 × 900 D400 covers
Plus, enjoy fast delivery – your order can be dispatched within 48 hours, ensuring your project stays on schedule without delays.
All manhole covers, gully covers, and frames are supplied through an external supplier. Delivery charges will be calculated in your cart at checkout. Due to the size and weight of these items, deliveries are typically made using an artic vehicle.
Please review all product specifications before placing an order. If you require assistance selecting the correct product, our team is available on 03338803558Â or info@drainageandcivilsdirect.co.uk to provide professional guidance.
- Product Reference: MDD9090DT10
- Product Type: Double Triangular Ductile Iron Highway Manhole Cover
- Load Classification: D400
- Clear Opening: 900 × 900mm
- Overall Frame Size: 1050 × 1050mm
- Frame Depth: 100mm
- Cover Configuration: Double Triangular – Lift Out
- Standard: BS EN124:2015
- Certification: Kitemarked
- Highway Compliance: CD534/HA104 Compliant
- Chamber Compatibility: Mainstream D400 Composite Chamber Systems
- Optional Extras: Bespoke Badges (FW/SW etc.) and Sealing Plate
- 150mm Alternative: MDD9090DT15
What size chamber does this 900×900 manhole cover fit?
The MDD9090DT10 is designed for a 900 × 900mm clear opening. It has an overall frame size of 1050 × 1050mm and a 100mm frame depth. For replacement installations, check all three dimensions against the existing chamber and frame before ordering.
Is this 900×900 D400 manhole cover suitable for highways?
Yes. This product is specifically designed for highway use and areas of heavy traffic. It is D400, BS EN124:2015 Kitemarked and stated by the manufacturer as CD534/HA104 compliant.
Is the MDD9090DT10 CD534 compliant?
Yes. The manufacturer’s datasheet states that this D400 range is CD534/HA104 compliant, making it suitable for consideration where a highway-specific specification is required rather than simply a general D400 load classification.
What is the difference between the 100mm and 150mm versions?
Both products provide a 900 × 900mm clear opening, D400 classification and highway specification. The MDD9090DT10 has a 100mm frame depth, while the MDD9090DT15 has a 150mm frame depth. Select the appropriate version according to the project specification or existing installation.
.Why would I choose the 150mm deep version?
Choose the 150mm version where the project specification or existing installation requires a deeper frame. Frame depth should be checked independently of the clear opening — two covers can both be described as 900 × 900mm while having different frame depths.
What does double triangular lift-out mean?
The MDD9090DT10 uses a double triangular lift-out cover arrangement, dividing the large access cover into triangular sections rather than using one large single-piece cover.
Can this cover be used with composite chamber systems?
Yes. The manufacturer states that this product is compatible with mainstream D400 composite chamber systems, making it suitable for highway utility, communications and other service chamber installations.
Is 900×900 a common manhole cover size?
Yes. 900 × 900mm is a commonly specified large access opening for utility, commercial and civil engineering chambers. However, the overall frame dimensions can vary between manufacturers, so the clear opening alone should not be used to determine whether a replacement cover will fit.
Will this replace my existing 900×900 D400 manhole cover?
Potentially. This product has a 900 × 900mm clear opening, 1050 × 1050mm overall frame and 100mm frame depth. Compare these dimensions against the existing installation before ordering, particularly where you’re replacing another manufacturer’s cover and frame.
Can the cover be supplied with bespoke badging or a sealing plate?
Yes. The manufacturer’s listed options include bespoke badging, such as FW/SW identification, and an optional sealing plate. Availability and lead time should be confirmed if either is required for a project.
What happens if I order the wrong size or frame depth?
Large ductile iron covers can incur significant return haulage and restocking costs. Before ordering, check the 900 × 900mm clear opening, 1050 × 1050mm overall frame and 100mm frame depth. If you’re unsure, send us your existing dimensions or project specification and we can help check suitability.





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