01952 588 885
Seating Rings/Adjusting Units
Made to BS EN 1917:2002 and BS 5911-3:2010 concrete seating rings/adjusting units are cost effective products that can be used in place of engineering bricks to adjust the ductile or cast-iron covers and frames to the required level on site.
Made from precast concrete stopping floatation and with fewer joints used, reducing the likelihood of infiltration, they can be quickly and easily installed, making life easier for everyone involved.
Type 2 – 600 x 600
One Part Unit
Type 2 – 675 x 675
One Part Unit
Type 2 – 750 x 600
One Part Unit
Type 2 – 750 x 750
One Part Unit
Type 2 – 900 x 600
One Part Unit
Type 1 – 600 x 600
One Part Unit
Type 2 – 600 x 600 (notch)
One Part Unit
Type 2 – 675 x 675 (notch)
One Part Unit
Type 2 – 750 x 600 (notch)
One Part Unit
Type 2 – 750 x 750 (notch)
One Part Unit
Type 2 – 600 x 600
Two Part Unit
Type 2 – 675 x 675
Two Part Unit
Type 2 – 900 x 900
Two Part Unit
Type 2 – 1200 x 675
Two Part Unit
| Manhole Type | Opening Size (mm) | Access Position | View PDF | Weight (kg) | Pack Size (No) | Thickness (mm) | Pack Weight (kg) |
| One-part | |||||||
| Type 2 | 600 x 600 | Central | 70 | 15 | 65 | 1050 | |
| Type 2 | 675 x 675 | Central | 60 | 15 | 65 | 900 | |
| Type 2 | 750 x 600 | Central | 66 | 10 | 65 | 660 | |
| Type 2 | 750 x 750 | Central | 80 | 10 | 65 | 800 | |
| Type 2 | 900 x 600 | Central | 75 | 12 | 65 | 900 | |
| Type 1 | 600 x 600 | Eccentric | 80 | 10 | 65 | 800 | |
| Type 2 | 600 x 600 (notch) |
Central | 63 | 15 | 65 | 945 | |
| Type 2 | 675 x 675 (notch) |
Central | 58 | 15 | 65 | 870 | |
| Type 2 | 750 x 600 (notch) |
Central | 78 | 10 | 65 | 780 | |
| Type 2 | 750 x 750 (notch) |
Central | 75 | 10 | 65 | 750 | |
| Two-part | |||||||
| Type 2 | 600 x 600 | Central | 48 | 15 | 65 | 720 | |
| Type 2 | 675 x 675 | Central | 56 | 15 | 65 | 840 | |
| Type 2 | 900 x 900 | Central | 50 | 10 | 70 | 500 | |
| Type 2 | 1200 x 675 | Central | 90 | 10 | 70 | 900 | |
| Lothian/ Corbet |
675 x 675 | Central | 280 | 5 | 150 | 1400 |
The advantages of adjusting units are:
- Designed to sit on top of the manhole cover
- Quick and easy to install by semi-skilled labour, reducing costs
- Eliminates laying engineering bricks on-site, reducing reliance on brick availability and cost increases, as well as vertical joint weak 65mm thick – similar to brickwork for consistency and comprehensive strength similar to Class B Engineering bricks – other thickness’ available for customer choice
- Fewer joints reducing the likelihood of infiltration
- Reduced risk of on-site damage and pilferage
Lothian Seating Slabs
The Scottish Water seating slab or Lothian Seating Slabs (access opening size) is designed to comply with Scottish Water Services Specifications.
It is used in place of engineering bricks to adjust the ductile or cast-iron covers and frames to the required level.
Lothian Seating rings are not affected by moisture, fire or lose their shape in normal groundwater conditions.
Seating Rings/Adjusting Units and Section 38 Agreements
Section 38 (Highways Act 1980) is the term for the legal agreement that allows a highway authority to “adopt” a road (meaning it will be maintained by the highways authority at the public’s expense) which has been constructed by a private developer for 5 or more dwellings.
The developer has to be able to prove that the road has been constructed in accordance with standards set out by the highways authority to enable the highways authority to be able to “adopt” it under a Section 38 legal agreement.
So in the case of concrete frame adjusting/seating rings; units manufactured to BS EN 1917 and BS 5911-3 are shown in both Manual of Contract Documents for Highways Works – Volume 3 – Highway Construction Details – F-Series and in Sewers for Adoption – they are therefore deemed to be accepted for use in highway construction and should not prevent a road from being “adopted” under a Section 38 agreement by a highways authority.
Note: Appearance of a hairline crack in a seating ring or gully cover does not signify failure or a cause for rejection.
Our multi-part adjusting units offer the advantage of light weight sections enabling one man to handle the units and comply with manual handling requirements.
All adjusting units/seating rings
It is the responsibility of the customer to check that the proposed cover and frame flange is fully supported by the chosen adjusting system as flange sizes may vary.
