FP McCann installs Large Precast Attenuation Tank at Holmfirth Housing Development
FP McCann has supplied and installed a large 195 cubic metres precast concrete panel tank for housing developer Orion Homes in Holmfirth, West Yorkshire.
Situated under a private access road, the attenuation tank is designed to alleviate flood risks and to cater for a 1 in 100 year storm surge event on the Vicarage Meadows development of 18 prestigious properties.
The tank is amongst a number of precast concrete types that are now accepted by Yorkshire Water within Sewers for Adoption 6th and 7th editions. It is also part of the FP McCann multi-purpose panel tank system range, which can be designed and installed up to 6 metres high with overall dimensions to suit the client brief.
Measuring 30 metres long by 5.4 metres wide at a height of 1.2 metres, the Holmfirth panel tank manages a storm event by capturing excess surface rain water. The water can then be released back into the drainage system at a controlled rate, thereby relieving the pressure on the main drainage network and reducing the risk of downstream flooding.
Prior to construction of the tank, a 75mm thick blinding layer of stone and concrete was formed to receive the foundation floor, a 300mm thick C40 concrete steel mesh reinforced slab. The panel sections were manufactured at FP McCann’s state-of-the-art precast facility in Byley, Cheshire and delivered to site and installed by the approved FP McCann specialist fixing team. In total, 14 walling units were fixed and 8 cover slab sections, including one with a single manhole access point. To complete the tank, a concrete screed was applied to the cover slab and the base was sealed with concrete that was poured into a timber shutter surround.
The off-line panel tank is connected to the end of a 600mm diameter precast concrete pipe storage system, to provide the additional overflow capacity on the development. Commenting on the panel tank choice and build, Ian Halliday Quantity Surveyor at Orion Homes says, “A precast concrete design was always our first consideration as Yorkshire Water have accepted the use of such tanks as adoptable systems through their stringent S104 approval process. Looking then at the economic viability of a number of competing systems, FP McCann’s multi-purpose panel tank design came out on top. It was then a pleasure to work with the McCann approved installation team who undertook the work in a safe and efficient manner. We will certainly consider similar FP McCann supply and install precast concrete panel tanks systems on future projects.”
Unlike the plastic crate system that cannot be inspected but gets silted well before its life expectacy, FP McCann’s precast multi-purpose panel tank system comes with a 100 year design life, can be easily inspected and, if required, cleaned and restored back to full functionality. It can be installed up to 6 metres high with no footprint size limitation and is designed for a range of loading criteria, including pedestrian through to LM1 highway loading. The use of precast concrete tanks allows an 85% reduction in on-site construction programmes. Internal design features such as weir and baffle walls can be added and penstocks or flap-valves can be preinstalled. Typical uses includes Attenuation Tanks, StormBrakeTM Chambers, Pumping Stations, Large CSO Chambers, ASP Structures, Basements and Clean Water Storage Tanks.