Round-in-Square Manhole Covers
A square frame with a circular cover inside: the square outer edge fits neatly into paved surfaces and kerb lines, while the round cover keeps the structural advantage of a circle — it cannot drop through, and it rotates freely without jamming on grit.
This type is common on asphalt carriageways where the frame must align with a rectangular excavation, and on sidewalks where a square outline looks tidier than a circle.
- Square frame [600]×[600] to [900]×[900] mm
- Round clear opening DN400 – DN700
- C250 / D400 / E600
- Hinged or lift-out cover
Selection Guide
Which Shape Do You Need?
|
Installation |
Recommended shape |
Typical class |
Reason |
|
Carriageway, highway |
Round / Round-in-square |
D400 / E600 |
Circular cover cannot fall through; even load distribution |
|
Footway, plaza |
Square |
B125 / C250 |
Larger opening in the same footprint; aligns with paving |
|
Asphalt patch repair |
Round-in-square |
C250 / D400 |
Square frame matches the rectangular cut |
|
Cable / valve chamber |
Square, two-part |
B125 / C250 |
Large rectangular opening for equipment access |
|
Airport apron |
Round, F900 |
F900 |
Highest test load, aircraft wheel loads |
FAQ
Manhole Cover Questions
1.What does “clear opening” mean, and why does it matter?
Clear opening is the usable round or square hole you actually get when the cover is removed — not the outside size of the frame. A DN600 cover typically has a [750] mm frame; buyers who order by frame size often end up with an opening that is too small.
2.Can I buy covers only, without frames?
Yes, but send us the internal dimensions and seating depth of the existing frame. Covers are matched to a pattern, not to a nominal size.
3.Do you supply covers marked with our municipality's name?
Yes — lettering and logos are cast into the pattern, not painted on. Provide artwork or a photo of the existing marking.
4.How do I stop covers being stolen?
Specify a captive hinge plus stainless steel locking bolts — the cover lifts for inspection but cannot be walked away with. See our anti-theft specification when enquiring.
Tell us the opening size
We will confirm the class, weight and container load for you.
