Drain Inspection Chambers and Risers

A complete drainage inspection chamber is built from several compatible components. The exact combination depends on the chamber system, pipework and required finished level.

Inspection Chamber Base

The base connects the chamber to the underground drainage run and provides channels and inlets for the adjoining pipework. 

Choose a base that suits the required pipe diameter and connection layout. Different inlet configurations are available, so check the drainage drawing and individual product specification before ordering.

Inspection Chamber Risers

An inspection chamber riser extends the chamber upwards from the base until the required access level is reached.

Depending on the system, multiple risers may be fitted together to achieve the required height. The permitted configuration and overall chamber depth vary between products, so follow the manufacturer's installation requirements for the chamber being used.

Seals And Restrictors

Seals are used between compatible chamber components to maintain the connection between sections.

Some deeper chamber arrangements may also require a restrictor or reducing component at the access opening. These aren't universal accessories, so check what is required for the specific chamber diameter and installation depth.

Inspection Chamber Covers And Frames

The cover and frame finish the chamber at surface level and control access to the drainage below.

They also need to suit the location and expected surface loading. A chamber in a landscaped or pedestrian area won't necessarily require the same cover specification as one positioned in a driveway or trafficked commercial area.

Browse our manhole covers and frames for compatible surface access products.

The chamber needs to work with the drainage layout, pipework, installation depth and access requirements shown on the project specification.

1. Choose The Chamber Diameter

Drainfast stocks three main inspection chamber ranges:

• 280mm inspection chambers for compact, shallow-access drainage installations
• 450mm inspection chambers where more access space or larger pipe connections are required
• 600mm inspection chambers for larger drainage systems where greater access and pipe capacity are needed

Larger isn't automatically better. The appropriate diameter depends on the drainage design, pipework, depth and access needed for future maintenance.

2. Check The Drain Pipe Size

Make sure the chamber base accepts the pipe diameter being installed.

Drainfast's inspection chamber range includes products for common drainage sizes such as 110mm and 160mm, with larger connections available within selected chamber systems.

Check each base carefully where several runs enter the same chamber. The main channel diameter, branch connections and inlet positions all need to match the intended layout.

3. Check The Required Installation Depth

The combination of the chamber base and risers determines the finished chamber height.

Maximum permitted depth varies between chamber systems, and deeper installations can require restricted access or a different chamber arrangement. Use the individual product specification to establish the correct configuration rather than applying one maximum depth across every chamber.

Need help specifying a chamber? Speak to the Drainfast drainage team before ordering.

4. Choose The Correct Cover And Loading

The surface above the chamber determines the type of cover and frame required.

Pedestrian and landscaped areas have different loading requirements from driveways, car parks and other trafficked locations. The cover classification, supporting construction and chamber system all need to suit the application.

Don't assume that the chamber riser itself determines the load the finished installation can withstand. Check the complete system specification, including the cover and frame.