DESIGN, BUILD, AND ENGINEERING


equipment, and the associated costs. As the Enfield site has signed a fixed price, managed service contract for 10 years, there are no ad hoc costs for the Trust.


Complex M&E services


To discover more about how CFES built the new facility, and its installation of the complex mechanical and electrical services, I recently visited the supercentre to meet CFES Projects director, John Davies, who firstly explained how the company won the contract to design and build the decontamination ‘supercentre’. He said: “From Invitation to Tender the Trust ran a rigorous selection, breaking the procurement down into four phases of dialogue and response sessions. Costed proposals were sought from prospective partners to provide outline solutions for design and build of an off-site facility to meet the Trust’s production requirements and future growth anticipation. Bidders were also asked to provide options for finance, maintenance, and operation of the service. At the time the Trust was still undecided as to whether to run the new decontamination supercentre with NHS staff, or to partner with a service-provider.


Competitors ‘whittled down’ “Thereafter the scheme went through a detailed and final tender stage, and, following the notification and standstill period, CFES was appointed to the project for Stage 2 – Design – in April 2017. We subsequently commenced construction on site that November, completing commissioning in April 2019.” The supercentre was fully ‘live’ by August 2019, with staff transferring over from the existing on-site facilities to the new off- site unit for all three hospitals in stages, to maintain continuity. John Davies said: "We have extensive experience designing, building, and equipping, off-site CSSD facilities, often in challenging locations, which stood us in excellent stead in winning the contract. CFES formed a specialist healthcare design team made


A view of the gas-fired steam boilers from above.


up of architects from Floyd Slaski, MEP engineers, ETA Projects, and structural engineers from ACIES.”


The building within which CFES constructed the new facility was formerly a large automotive parts centre/ supermarket. John Davies explained: “Once landlord negotiations, lease agreements, and planning consents for a change of use had been concluded, we took possession of the site, and were faced with a large empty warehouse, with the slab still marked out with the vehicle bays used by the previous occupant.” Works began with cutting and break-up of the existing slab to form new drainage channels. A network of new process below-slab drainage was installed in stainless steel tube to serve washers, autoclaves, and new plant. The main plant is located on a two-storey, steel mezzanine structure. John Davies said: "The mezzanine support columns and structure are independent to the main warehouse portal frame. We utilised a driven pile solution to form the pile caps. The mezzanine structure at first floor predominantly accommodates the new full fresh air ventilation and water services plant, with the upper floor allocated to heating and chilled water distribution headers, expansion equipment, and pump sets.”


Six ventilation turrets A steam boiler blowdown vessel.


CFES trimmed and ‘opened up’ the roof, and ‘landed’ six sizeable ventilation turrets on each opening. On one side these draw fresh air in through the ventilation plant, while the turrets on the opposite side handle the exhaust air after heat recovery has been undertaken. John Davies explained: “The turrets provide a practical solution for maintaining good air quality, minimising debris/airborne contaminants being drawn in, and ensuring suitable


separation to avoid any short-circuiting of fresh air intakes and exhausts. Using roof- mounted turrets also enabled us to bring in and exhaust air without taking up large sections of either the front or side of the building for ventilation louvres, with the potential associated noise issues for neighbouring properties.” The building’s 14 metre height necessitated CFES using crash decks and netting, and the need for a long reach required the use of a tower crane to lift on the roof turrets under controlled operations. Multiple crane lifts using mobile cranes were undertaken for erection of the mezzanine steelwork, and lifting heavy plant such as air-cooled chillers onto the external plant area. I asked if there had been any challenges getting the cranes onto site. John Davies said: “In fact the logistics of bringing cranes onto site, and their safe operation, were as challenging as the work we often undertake within constrained hospital sites, frequently close to ‘live’ clinical areas, roads, and sometimes railways, despite us not having to contend with such challenges here. The standalone site here not only had good access, but also ample space in the yard at the front, while excellent ground properties reduced the need for extensive load spreading.”


Laying the main services Returning to the construction process, and John Davies explained that as part of its contract, CFES undertook enabling services for the main utility provider, to satisfy requirements for a 150 mm natural gas main and duplex metering station, 90 mm mains cold water service, and 1 MVA sub-station. Removing foul, waste, and effluent drainage from the unit was a challenge. Due to the proximity and location of the existing main surface and foul sewers, a gravity solution to the drainage was not feasible. Instead, CFES


August 2020 Health Estate Journal 45


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