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CPM Concrete Reducing Slab.
  • CPM Concrete Reducing Slab.

1500 x 900mm Concrete Reducing Slab



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Product Details

This item is supplied to order and additional refund & returns terms apply.


Product Type: Concrete Reducing Slab
Model Type: Non-Stepped
Chamber DN: 1500mm
Approx Overall DN: 1710mm
Reducing Section DN: 900mm
Approx Maximum Depth: 250mm
Approx Weight: 1060kg

This reinforced concrete reducing slab is designed to reduce the size of the access point opening in concrete manhole chamber rings that have a 1500mm nominal diameter. Reducing the opening to 900mm allows a manhole chamber construction to change from using 1500mm rings to 900mm rings

Product Features at a Glance:

  • 900mm dia reducing section
  • Eccentric access positioning
  • Cast in lifting rungs
  • Fits flush to the chamber ring
  • Manufactured from reinforced concrete

This is a Non-Stepped model making it suitable for use with non-stepped manhole chambers. According to guidelines from United Utilities, when the distance from ground level to the benching landing area of a manhole chamber is in excess of 3m, step irons are not permitted and a ladder must be installed. Non-Stepped chambers and reducing slabs are therefore ideal for these situations as a proper ladder system can be installed without obstruction. If unsure about the regulations, please contact our technical team for more advice or consult directly with United Utilities to confirm the relevant specifications for your project.

Concrete reducing slabs, are used in the main shaft construction of manhole chambers. Sitting on top of a larger chamber ring, they create an access point opening that allows the chamber construction to be continued with a smaller diameter chamber ring. Reducing slabs from CPM also benefit from cast in lifting rungs to aid in the safe positioning of the slabs onsite.

For manholes installed at shallow depths larger opening sizes are usually required, to permit standing/crouching space, but they are not always suitable for deeper depths. In a deep manhole installation, the lower manhole rings will be larger to accommodate the diameter of the pipe connecting to it and to meet the the required safe working space needed for man-entry. Once all minimum requirements are met however, the access shaft part of chamber can be "chimnied" up to a small ring size. Doing so reduces the hazard risk of the manhole should the cover ever be removed, and can help to reduce the overall project cost.

 Key Features of CPM Concrete Products:

  • Quality - Precast concrete drainage products are manufactured in accordance with the relevant BS EN 1916/7, BS EN 5911 and CE marked where applicable. Goods are certified by Quality Assessment under the Kitemark Scheme and ISO 9001:2015.
  • Sustainability - Concrete pipeline systems are one of the most sustainable options available, they are manufactured from responsibly sourced materials, and can be made using recycled aggregates and cement replacements.
  • Proven Strength - They have a proven life of over 120 years, in normal groundwater conditions, are not weakened by fire or moisture and do not lose their shape. They are resistant to DC4 and impacts such as jetting, so blockages can be cleared easily.
  • Installed Cost Savings - Precast concrete pipes are rigid structural elements that do not always require a full granular surround, saving time in bedding and compaction. Excavated material can be reused and imported granular material can be reduced to a minimum.
  • Durability - Due to the inherent strength and durability of the Marshalls CPM precast concrete products, they are highly abrasion and corrosion resistant and don't lose strength over time.
  • Design Flexibility - Precast concrete drainage products can be used for a number of purposes, including sewerage and sustainable urban drainage systems (SuDS) applications such as stormwater attenuation and storage.
  • Water Tightness - Concrete pipes and manholes are designed to be watertight and are tested to pressure levels equivalent to a 5 metre head of water.
  • Fire Resistant - Concrete is naturally fire resistant. 

Please Note: 
All dimensions and weights are approximate as concrete product dimensions can have slight variations due to their manufacturing process. Customers should ensure that lifting equipment has sufficient capacity to allow for variations. All images shown are used for illustration purposes only and may differ from the actual product supplied. 

16-20 working days
Product Type:
Manhole Reducing Slab
Marshalls CPM
Nominal Size: