WET News

OCTOBER 2014 WET NEWS 19 Wessex Water needed to improve the protection of two impounding reservoirs, both of which were constructed in the late 1800s, with modern-day thinking. The challenge: Securing ageing structures R etrofitting security sys- tems to Victorian water engineering can pose challenges. Pioneering in their day, these ageing structures now rely on 21st century inge- nuity to extend their service life and bring them in line with modern security and operation- al standards. This was true of Wessex Water's project to en- hance the protection of two im- pounding reservoirs in Somer- set, constructed in the late 1800s. The contract involved the design and build of physical and electronic protection meas- ures, compliant with current government guidelines and standards. Central to this has been the engineering of high security access systems for valve towers sited within the reservoirs. INSIGHT SECURITY Groundworks for the high security Ultrasecure mesh building included landscaping, concreting and installation of a specially designed former base system The access solutions have met tough challenges, both in their design and water-borne installation in compliance with construction, safety and hygiene standards. In addition, site logistics needed careful planning to minimise the impact of construction and mobilisation of materials within the sensitive environment. Differences in the construc- tion of the towers were a further complication. Luxhay reservoir is served by a tunnel that required a high security door with egress for bats, and a mod- ular mesh cage building to fur- ther secure surface access. Access to Leigh reservoir is via a single entry point on top, necessitating the installation of a secure access cover enclosed within a high security cage as an additional deterrent. A floating platform held the key to security upgrades of valve towers at impound reservoirs – built more than 100 years ago. A solution: Towering feat of security T echnocover undertook de- sign, manufacture and in- stallation of the high secu- rity access equipment. The company offers a concept-to- commission 'Total Service' ap- proach to water security projects, focused on delivering best value solutions from its LPCB approved range or bespoke service. This in- cludes site survey, security con- sultation, in-house design and manufacture, system installa- tion, life-time maintenance of products, and, in the case of Wes- sex' impounding reservoirs, act- ing as principal contractor. Integral to the site solution was a pontoon, transporting materials and providing an 8m square work platform around the water-locked towers. As well as supporting up to eight operatives at any one time, it needed to carry a mechanical li‹er with 350kg li‹ capacity for moving components into position. Using proprietary grid mod- ules, Technocover designed a floating platform for a 1-tonne maximum load capacity over 4m square and a half tonne point load within the same footprint. It was 90% preassembled bank side and used to transport tools, product components and li‹ing equipment to the towers accompanied by a safety boat. The final platform section was then added as the pontoon was fixed into position ready for work. Groundworks for the modular mesh cage building system also required special attention. Following a structural survey, Technocover designed and man- ufactured a special galvanised steel former system for concrete infill on site to protect an existing staircase from any loadings. This offered a faster method of construction and, therefore, the lowest cost solution. To ensure programme efficiency, Technocover worked closely with Wessex Water at design and approval stage. This allowed detailed fine-tun- ing of product design, installa- tion and site logistics for a "right first time" outcome. Joe Hughes, Wessex Water's site manager, said: "The product solutions needed to offer an ele- ment of flexibility while comply- ing with current legislation, being fit-for-purpose and, as far as possible, visually unobtrusive. "Technocover refined design details to accommodate all these and other issues including plan- ning permissions, land-owner views, and environmental con- siderations such as the bat aper- ture in access doorways." The comprehensive planning paid off, even when the April build programme was hit by unexpectedly wintry conditions. "Work needed to meet the agreed deadline, and weather conditions couldn't have been worse, with snow, wind, rain, short daylight hours and extreme cold," said Hughes. "It le‹ Tech- nocover with a vast amount of work to complete in little over two weeks of actual site time, but they managed to achieve it." He added: "Any water-borne job in such adverse conditions needs careful workforce supervi- sion and health and safety man- agement. Technocover's safety manager was present throughout to supervise and react on the spot to any issues." In working with restricted operations, the installation team were required to observe a par- ticularly complex set of safe working and hygiene practices. These included strict procedures for chlorination of pontoon com- ponents, safety boats and equip- ment, as well as complying with safety guidelines for working on water, at height and from a float- ing work platform. n THE CONCEPT • Retrofit high security access covers, escape hatch, door and mesh cages for Victorian reservoir towers • Water-based and land-based installation challenges • A pontoon, transporting materials and providing an 8m square work platform around the water-locked towers, was central to the projectr and velocity calculator is highly accurate in pinpointing leaks on any materials of pipe or multiple pipe types, avoiding dry holes • Technocover designed a floating platform for a 1-tonne maximum load capacity over 4m 2 NEED TO KNOW 1 90% of the floating platform was preassembled bank side, and used to transport tools, product components and lifting equipment to the towers accompanied by a safety boat. 2 The installation team were required to observe a particu- larly complex set of safe working and hygiene practices 3 As well as supporting up to eight operatives, the pontoon had to carry a mechanical lifter with 350kg lift capacity for positioning components THE VERDICT "Enhancing security at the two reservoirs has been a challenge requiring careful planning and close liaison between all parties. The innovative security and installation solutions delivered by Technocover have improved both site security and employee safety at these sites." Ian Blair, head of Health, Safety & Security at Wessex Water "Work needed to meet the agreed deadline, and weather condi- tions couldn't have been worse, with snow, wind, rain, short day- light hours and extreme cold," Joe Hughes, site manager, Wessex Water The pontoon solution concludes a rigorously managed three-year programme of security upgrades in line with regulatory standards

• Cover