The site includes two access/egress points for resilience with a ‘one way’ pattern of movement for custody vehicles through the secure yard.
A clear separation of visitor and staff entrances is incorporated, featuring the visitor entrance to the main building and frontage. The staff entrance is more discretely located to the side of the building, behind the secure yard fence, for added security.
The secure yard area is enclosed by anti-climb ‘352’ weldmesh fencing and heavy duty automatic sliding gates at each control point.
The main building structure is to be a steel frame solution with composite floor construction to form upper floors.
A service void is provided over the custody accommodation to improve access for maintenance and minimise disruption to operational processes.
The structural specification generally follows the table below
|Normal Form of Construction||Abnormal Form of Construction|
|Mass Concrete Pad Foundations Supporting Steel Frame without Ground Improvements
Assumed Bearing Pressure 150kN/m2.
|Reinforced Concrete Pads on Vibro Compaction Ground Improvement or Piled Foundations|
Strip Footings Supporting External Perimeter Walls and Cell Internal Walls without Ground Improvements
Assumed Bearing Pressure 150kN/m2.
|Reinforced Concrete Ground Beams Bearing onto Reinforced Concrete Pads or RC Pile Caps|
|Ground Bearing Slabs with Mesh Reinforcement||RC Suspended Ground Beams Bearing onto Perimeter and Internal RC Ground Beams|
|No Harmful Gas Protection Required Under Ground Slabs||Under Ground Slabs Gas Protection and Ventilation Required|
|Uncontaminated / Inert Excavated Material off Site||Contaminated Excavated Material off Site|
|Level Site without Major Cut and Fill
Earthworks and Retaining Walls
Assumed CBR 15% for the external works build-up
|Sloping Site with Major Cut and Fill Earthworks with Building and External Retaining Walls|
|Surface Water Discharge Unrestricted without Major Attenuation and Final Outfall within Site Boundary
Assumed average depth 2.5m.
|Surface Water with Limited / Restricted Discharge Requiring Underground Attenuation. Final Outfall off Site|
|Foul Water within Site Boundary
Assumed average depth 2.5m
|Foul Water off Site / Beyond Site Boundary|
|No Major off Site S278 Highway Works. Entrance / Exit Bell Mouth Highway Works only||Off Site S278 Highway Works Required|
The cells are to be formed out of pre-cast concrete walls and roof slabs, with the steel frame to support the roof sitting on top of the pre-cast concrete panels in this area.
All cells are to include daylight admission with approved window or sun-tube installations.
All cells are to include a tiled internal finish to the walls and direct decoration to the roof slab as a ceiling finish.
Other ceilings, where accessible to detainee movements, are to be of secure acoustic metal tiles in a suspended ceiling system, or plasterboard.
Internal custody walls, where not pre-cast concrete, are to be in dense, solid concrete blockwork to meet requirements for robustness and acoustics.
The Main and discrete Charge Desks are to be finished in Corian or other similar solid surfacing where exposed to contact with detainees.
This specification was developed in close consultation with the Home Office and is now being refreshed with the MOJ in order to achieve continuing compliance in keys areas whist still retaining the ability to be customised to suit any individual Police Forces needs such as: