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Duct Access Chambers & Duct Boxes

Needing duct access chambers for your underground drainage system or complex cable network? You’ve come to the right place.

Our Naylor metro access chamber/Duct Box is made from 100% recycled material and come in a range of sizes, but are all identical in their high quality and ease of use.

To install, simply open the ducts, excavate the ground, make a bed of pea shingle, place the box inside, connect up your drainage pipes and finish by surrounding with concrete!

If you need any extra help, just give us a ring or shoot us an email, otherwise, order with confidence and we’ll get your chambers to you quickly with our fast and free delivery.

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More information on duct access and inspection chambers:

If you're planning on creating an underground drainage system or you're dealing with a complex network of cabling (for street lighting or traffic signals for instance), you're going to need to have access to that system for maintenance and to deal with drain blockages should they occur. Here at EasyMerchant, we've got a massive range of products designed exactly for this need - and we've got a wealth of product knowledge to help you should you need any support.

This is where duct boxes and an access chamber are essential.

An access chamber is often still referred to as 'manholes' - although the design had changed significantly with the advent of new materials and technologies. In times gone by, a manhole was a brick-built chamber that allowed people to climb down into the sewer system below. Today though, tough plastics are used - and new cleaning technologies mean people simply do not need to enter modern underground drainage systems - so the chambers are much smaller.

What does a chamber comprise of?

An access chamber is actually just one part of three different components that make up an 'inspection chamber'.

As the name suggests - an access chamber allows you to check the flow moving through a drain. At the bottom of duct access chambers, there's a ducting box - where various flows from surrounding drains all past through. On top of this, there's a riser - or manhole chamber section. This part is designed to give the chamber height - between the surface level and the drain.

On top of the riser, a manhole cover will sit. This is usually a galvanised frame and a tough plastic or cast-iron cover.

How do the parts fit together?

The three sections of inspection chamber are designed to fit together neatly - with a rubber seal making sure there's a watertight connection. Our risers are available in a variety of sizes - so they can be stacked on top of one-another to give you the height you need. Again, on top of the risers, the cover connects with a rubber seal - making installation quick and simple - despite being completely watertight.

If you do need to adjust the height of your riser sections, you can adjust them to the necessary height using a fine-tooth saw. There are guidelines moulded into the plastic to make it easy to get an accurate cut.

How deep should you go?

Generally, drainage systems will sit at around 1.2m under the surface - however, if you require a greater height from the risers, you can install down to 3m.

It's worth remembering that drains over 1.2m will need a restricted access cover. A cover like this sizes the access down to 350mm - a much smaller size to ensure even children could not inadvertently fall down down the chamber when it's open.

Installing the right duct

We provide Naylor Modular duct boxes - as they're designed to be as flexible as you need.

The box has 12 possible inlets - each of which can be cut to the exact size you require. What's more, the boxes are stackable - with a maximum of 3 boxes creating 36 possible inlets.

Building regulations state that duct boxes need to be installed on a suitable bedding material. This doesn't necessarily mean a concrete surround though - assuming the bottom of the trench you've created is stable, a pea shingle bed that's around 150-200mm deep is perfect for the job. This is also perfect for backfilling around your duct boxes.

You should ensure that any unused duct inlets have blanking plugs in place.

Manhole covers

Again, our manhole covers are from the same modular Naylor system product range - and every size has a 12.5 tonne load rating. This weight allows for use in virtually any setting - even industrial yards, road, and highway locations.

As well as being tough, the composite material used is non-slip.

Security is vital when installing a manhole cover - not only to protect against unwanted access - but also to prevent injuries. Our manhole covers feature integral lifting keyholes and are approved by virtually all local authorities thanks to their high build quality and excellent safety ratings.

We're here to help

Got a question about inspection chambers? Curious to know more about access boxes or channel drainage in general? No problem - we're here to help with your project, no matter which stage you're at.

Perhaps you're browsing our site considering different parts? Or maybe you're waist-deep in a trench and you've run into a problem. Either way, you're welcome to call, email, or use our instant messaging service to talk to one of our expert customer service team.

At EasyMerchant, we understand your trade - and we've got a huge range of experience to back up our products.