Back to Basics: Measuring a Manhole Cover
Whether you call it a manhole cover, access cover, inspection cover or drain cover, the method to measuring the product doesn’t change, yet isn’t done how one would naturally assume.
If you size up a tile, a paving stone or whatever else, you of course measure edge to edge. However, this isn’t typically the case with manhole covers.
Take a look at the image below, using a generic recessed tray and frame as an example.
Manhole covers are described and specified by their clear opening size.
As you can see, the clear opening is actually the hole within the frame; the smallest hole. This also corresponds with the chamber hole size in the ground. So, when you see a 600 x 450mm or 750 x 750mm product on our websites, this always refers to the clear opening.
One would assume you measure the full size of the existing cover, and we can specify based on these dimensions, but ideal practice is as above. If you click the two links you’ll see all our products provide the overall size as well, to provide clarity before you order.
It is mostly for this reason why covers of incorrect size are purchased, returned and replaced. This in turn increases the amount of time and money spent on acquiring something that, one would assume, is a relatively straightforward piece of equipment.
Sometimes, even when measured correctly, it can be difficult to find the perfect cover to suit your needs. This is why we offer a bespoke fabrication service, specially designing and manufacturing a manhole cover and frame to match your requirements. These can range from a simple 250 x 250mm offering to nine-tray 1500 x 1500mm monsters. Whatever the problem, we can find the solution.