Cast Iron Manhole Covers

Cast iron manhole covers: the choice where vehicles drive over

The cast iron manhole cover is the one to install when weight is going to pass over the manhole. It closes the box through which the cabling of the outdoor installation runs and, in this material, the criterion is not aesthetic: it is structural. On a manhole located in a vehicle access, a dropped kerb or a manoeuvring area, the cover takes a wheel every day. Cast iron stands up to that demand without deforming, and that is why it is the go-to family wherever there is vehicle traffic.

Why cast iron where there is traffic

Three practical reasons. Strength: cast iron takes the high load classes, which are what an area with vehicles calls for. Weight: a cast iron cover stays where you put it, it is not lifted by a passing wheel and it does not rattle in the frame, and that firm seating avoids noise and wear in the housing. And behaviour over time: it takes heavy use and the weather without losing its shape.

Load classes: how to decide between C-250 and D-400

The load class is the figure that governs the purchase, and in cast iron the two that concern you are C-250 and D-400.

• C-250: hard shoulders and gutters, that is, road edges where a wheel treads occasionally. It suits parallel parking strips, edge zones and track gutters.
• D-400: carriageway with traffic. This is what you need if the manhole sits on a traffic route, on a dropped kerb vehicles cross daily or in a manoeuvring area.

Decide by the real use of the spot, not the use it had when the work was done: if the manhole ended up at the side and vans drive over it today, the class that applies is today's. And be careful not to fall short, because that does not mean the cover lasts less, it means it sinks or breaks.

Frame, opening and maintenance

The cast iron cover always works with its frame: the surround takes the load and passes it to the paving, so a badly seated frame ruins a perfectly good cover. It is opened with a handle or a key, and that is worth bearing in mind because a cast iron cover is heavy: if the manhole is opened often and one person handles it alone, that weight counts. It asks for little maintenance. Check that the seating of the surround stays clear of soil and gravel, because a foreign body there makes the cover sit badly and start to move.

What to consider before buying

Start with the traffic: look at what passes over the manhole and that already gives you the class, C-250 for edges and occasional passage, D-400 for carriageway and vehicle accesses. Then check the internal opening of the manhole, which in the usual construction formats runs from 40x40 to 80x80 cm, and make sure the recess where the surround sits is sound. With those two figures, traffic and opening, the cover you need is defined. If you are still comparing materials, the general guide is in the manhole covers category.

At FactorLED you will find cast iron manhole covers in load classes C-250 and D-400. Look at what passes over the manhole and choose the class that matches that traffic.

Frequently asked questions about cast iron manhole covers

Why choose cast iron and not steel?

Because it takes the high load classes. If vehicles drive over the manhole, cast iron is the right material.

C-250 or D-400?

C-250 for hard shoulders, gutters and edges with occasional passage. D-400 for carriageway with traffic, dropped kerbs and manoeuvring areas.

Does a cast iron cover need a frame?

Yes, it works with its frame, which is what takes the load. Always check that the assembly sits properly in the paving.

Does it need maintenance?

Very little. It is enough to keep the seating of the surround clean: accumulated soil and gravel make the cover sit badly.