Rob Brown’s refurbishment of the services in this five-storey building included the poser of how to instal a 27-tonne prefabricated riser in three sections from the basement to a new roof-mounted plant deck. The problem: the sheer hulking size of the riser was in ludicrous contrast to the scant elbow room available for threading it down through the concrete floors of the building.
The existing building structure meant the opening required for the riser was nothing like as large as the mechanical consultant had hoped for after it became apparent that no more of the concrete floor could be taken out. With the ductwork already designed by this point, the size of the riser was fixed, leaving a space of just 30mm around each of its four sides.
Manoeuvring a nine-tonne piece of riser dangling and swaying from a crane hook into place without damaging the existing floors, the new plant-room steelwork or the riser itself is anything but a piece of cake. The crane chains holding the sides of the riser were so close to the new steelwork that there was a real risk of them jamming, leaving the riser stuck. The success of the operation owes everything to Rob’s decision to have four separate teams guiding the riser painstakingly through the building.
For a project that needed to be complete in time for full-on usage of the library in the new academic year, the late release of designs for the basement plant room was a major problem. It held up the commissioning of the new M&E under new raised access floors on the top two storeys. Rob therefore put in temporary pumps to flush the system through (as part of the commissioning process) while progress continued in the basement where the permanent pumps were being installed. By resequencing and building hoardings around the prefabricated riser and the temporary pumps, Rob was able to release the floors to the client in time for the new year student influx while retaining enough access to commission the systems.