Choosing the right manhole can easily be a daunting task. This is especially the case if you don’t deal with manhole covers all the time. Although they appear to be self-descript, manhole covers come in many sizes, dimensions and materials. If you don’t choose the one that is correct for the task in hand or you ignore a damaged cover and don’t replace it correctly you are in danger of something nasty occurring.
It can’t be stressed enough that a crack, however apparently slight and small, in a manhole cover, poses a serious risk. It can detrimentally affect the strength of the cover. It is, therefore, crucial to report or replace broken manhole covers as soon as possible.
You don’t want anyone to step on a damaged manhole cover and fall through it. It can cause a wealth of problems for all concerned.
What Are Manhole Covers?
Manhole covers are essentially removable discs or squares that cover access points that lead to drains and sewerage systems like the EasyMerchant manhole cover.
Wherever you are in the world, it’s highly likely that there will be a manhole cover nearby. They are most commonly found on pavements and roads, driveways and loading bays and are often in areas like docks and airports. As soon as you start looking for them you’ll discover just how many and how varied manhole covers there are!
Getting The Correct Sized Manhole Cover
When you measure the space for any manhole cover it’s important that the correct dimensions are recorded. Because manhole covers need to sit securely over the hole that’s being covered, you need to ensure you measure the inside dimensions of the hole from brick to brick on which it will sit. This is not to be confused with measuring the size of the cover that is being replaced. To be as accurate as possible it is advisable to measure in millimetres.
Choice Of Material
Cast & Ductile Iron Manhole Covers
Cast Iron and Ductile Iron manhole covers are strong and resilient. In general expect them to carry a maximum weight load of 40 tonnes. They are generally found on main roads and in areas that get high traffic like public car parks.
Galvanised Steel Manhole Covers
Galvanised steel manhole covers are lightweight and easy to install. They are surprisingly strong, and can typically carry as much as 17 tonnes of weight. This renders them ideal for spaces like domestic driveways as they can easily handle the weights of family cars, vans, SUVs and 4X4s.
Recessed Covers
Recessed manhole covers are perfect if they need to match the look of the driveway or patio’s landscaping. The recess enables paving slabs or standard block paving to be laid on top, up to a depth of 60mm. The Manhole covers will then blend in to their environment.
Polypropylene Plastic
Polypropylene manhole covers are typically laid where weight bearing would be no more than ‘light duty’, which is regarded as up to load class A15 and carries no more than 1.5 tonnes. They are generally to be seen in domestic, pedestrian only driveways.
When you select the material of a manhole cover to cover sewage or water, always consider the weight bearing necessary. If you are ever unsure always over estimate. If you underspecify to save money – someone may get badly hurt.
