Description
The rectangular manhole base 5 inlet is used to create an inspection chamber access point within a 110mm underground drainage system. It provides access for inspection, rodding and maintenance where drainage pipework needs to be checked or cleaned after installation.
This Polypipe UG490 rectangular chamber base is designed for 110mm inspection chamber layouts. It has a 610 x 460mm rectangular chamber size and is commonly used on domestic drainage, extensions, garden drainage, repairs and light-duty site drainage work.
The rectangular layout gives installers practical connection options where pipe runs need to enter the chamber from different directions. As a result, it is useful where a standard round chamber layout is not the best fit for the drainage design.
Rectangular Manhole Base for 110mm Drainage
The rectangular manhole base forms the lower section of a compatible rectangular inspection chamber. It allows 110mm underground drainage pipework to connect into the chamber while keeping future access available.
Polypipe lists UG490 as a 610 x 460mm rectangular chamber base for 110mm inspection chamber systems. The official guide describes it with 4 side branch inlets, 2 left hand and 2 right hand 90° connections, plus a main channel through the chamber.
- Rectangular manhole base for underground drainage
- Polypipe product reference UG490
- 610 x 460mm rectangular chamber base
- Designed for 110mm inspection chamber layouts
- 4 side branch inlets listed by Polypipe
- Main channel inlet and outlet are plain end
- Supplied with 3 blanking plugs
- Useful for inspection, rodding and maintenance access
Rectangular Manhole Base 5 Inlet Layout
The rectangular manhole base gives practical branch connection options for 110mm underground drainage systems. The side branch inlets help pipework enter the chamber from different directions.
Before installation, check the pipe route, flow direction, inlet positions, invert level and finished ground level. Then blank off any unused entries before the chamber is backfilled.
Polypipe notes that the main channel inlet and outlet are plain end. Therefore, couplers or socketed pipes may be required to complete the connection.
Rectangular Manhole Base Installation Use
Install the rectangular manhole base as part of a properly supported underground drainage chamber system. Good bedding, support and backfill help keep the chamber stable after installation.
The Polypipe guide states that the rectangular inspection chamber depth should not exceed 1.00m. Always confirm the final chamber depth, cover type, loading requirement and finished ground level before installation.
This product is a chamber base only. It is not a riser, cover or frame on its own.
Polypipe UG490 Rectangular Chamber Base
This Polypipe UG490 chamber base is useful for builders, groundworkers, landscapers and drainage installers working on 110mm underground drainage layouts.
Use it on suitable domestic drainage layouts, garden drainage, extensions, repairs and light-duty site drainage work where a compatible rectangular chamber is required.
Compatible Rectangular Manhole Products
This rectangular manhole base is part of the wider TWS manhole chamber base range. It can be matched with compatible rectangular risers, covers, frames, 110mm drainage pipe and underground drainage fittings.
View rectangular manhole bases at TWS.
View all manhole bases and inspection chambers at TWS.
View 110mm underground drainage products at TWS.
Shop all underground drainage at TWS.
For general UK drainage guidance, see Approved Document H: Drainage and waste disposal.
