CASE STUDY | THE OWO HOTEL accommodate fewer, larger units, he says. To aid cooperative working and coordination on this complex conversion, the entire project team worked in Autodesk Revit 3D building information modelling (BIM) software. Hume describes the BIM model as an absolute monster, with more than one million elements, 400,000 of which are related to the mechanical and electrical services. What was fantastic was having this digital design tool combined with a building that already largely existed so, if we were struggling to route a service digitally, we could get up and walk to the actual space, which was particularly useful when explaining to those new to the project. Even with digital scans, the engineer was still presented with some surprises. For example, when part of the ceiling was removed the team exposed a series of beams that had been added in World War II to provide enhanced protection to a particular area. The services had to be routed around the reinforcement. Perhaps the biggest challenge was in getting the building services from the basement plant spaces to the hotels upper levels avoiding many of its listed rooms located on the ground floor. This floor is full of double-height spaces with minimal ceiling voids and some major structural elements, so we made the decision at the outset to avoid using this space, says Hume. Fortunately, Aecom was able to make use of what Hume calls the moat an existing subterranean corridor located at lower ground level that encircles the entire building, following the line of the faade. Using the moat gave us the opportunity to circumvent the entire building to distribute the services, he explains. From the plantrooms on basement levels, services rise up to lower ground level, from where they are routed to the moat. From here, the various services follow the buildings perimeter until they reach the point on the plan closest to where they are required. From the moat, the services are routed up, through the ground floor, to Level 1, where a deep ceiling void provides the space for them to transfer from the buildings perimeter to the foot of a series of internal risers, concealed within the walls, that deliver the services to the upper floors. For the guest rooms, services from the risers connect to fan coil units (FCUs) to provide heating and cooling. The buildings windows are designed to remain 36 October 2023 www.cibsejournal.com Aecom used the moat an existing subterranean corridor at lower ground level that encircles the entire building, following the line of the faade Windows in the guest rooms are designed to remain closed, partly because of security reasons