The Meadowhall site at 11,000 M² is their largest site in Sheffield and houses 3 large hydraulic presses as well as heat treatment and machine shops manufacturing complex metal extrusions and forgings used by industries across the globe.
Close to the river Don and having Blackburn Brook running through the site the risks associated with flooding are ever present so following the serious floods of November 2019 the decision to protect the sites critical assets from future flooding was taken and an outline scope of works was developed that went out to tender in September 2020.
M3 Global Flood Technologies Ltd - M3Floodtec were awarded the contract and works began at Meadowhall in March 2021. The accepted proposal included a mixture of flood technologies for both above and below ground to protect the site and following the guidance of the flood risk assessment the recommended protection level including an allowance for some freeboard which was set at 34.8m AOD this equated to a maximum depth of 1.05m at the lowest point on the plan.
A mixture of various sized non return valves and surface mounted flap valves were installed in the surface and foul water drains to stop backflow waters entering into the drainage systems and in other locations existing manhole covers were replaced with sealed bolt down covers all of which are passive and come into operation as soon as the water starts to rise above the pipe invert levels.
The site is dependent on forklift trucks to move the forgings from building to building so level thresholds across the main roller shutter doors was a fundamental requirement in the scope. To facilitate this M3Floodtec proposed a combination of Defender barrier walls which are a demountable system consisting of single piece flood boards and intermediate posts which are deployed prior to a flood event into ground sockets and side channels that are permanently installed across the door entrance.
Pedestrian access into the buildings and offices is serviced with the installation of Defender hardwood flood doors and Steel emergency escape flood doors as singles and double units to match the existing openings.
The Electrical transformer and sub station buildings had 5 openings that required flood protection but also had to maintain a good air flow to aid cooling. M3Floodtec designed and installed 5 steel flood gates, 4 singles and 1 twin leaf units with open mesh tops at widths of 1.8, 3.0 and 5.4m to achieve the required flood protection.
Several of the buildings had steel cladding to ground level that offered zero flood protection so to accommodate this reinforced concrete block walls were designed and constructed inside the existing cladding and the existing single skin brick walls were strengthened with an outer skin of high density concrete blocks all of which were sprayed with polymer tanking and antiflood airbricks installed replacing the existing terracotta units.
The most critical location at the works were the 2 hydraulic Press’s, the 3,500t Bliss and 5,500t Davy units with supporting infrastructure. For these units a double flood protection was installed, designed to protect inundation from any direction.
Externally Defender wall barriers, steel flood doors and duct sealing was installed and internally, 2 welded steel panel walls supported by a reinforced concrete and block walls were constructed with additional access provision being provided by 2 deployable defender wall systems and 2 pedestrian steel swing gates.
Finally, to facilitate early warning of an impending flood event, 2 wireless remote GSM flood alarms were installed at either end of the site which were set at the critical trigger levels decided by the Client. These are sited in the Blackburn brook open channel and in one of the existing drainage manholes and when activated will send GSM messages on up to 8 different devices.