We took the design from stage 3 to 4 and were tasked with replacing the existing AHU & chillers on the roof of the Lloyds building at 25 Gresham Street with new modern high efficiency chillers and heat pumps, to assist LBG with their carbon reduction, reduce energy costs and the amount of GWP refrigerants and to reduce the heating load required from the existing boilers. The project commenced on site during the beginning of COVID and as such the building was unoccupied. We installed temporary chillers and connected them to the main chilled water flow and returns of the CRAC units int the two comms rooms. This allowed us to isolate the existing chiller and associated services for strip out by others and maintained services to the building.

Multiple crane operations were necessary to lift the new AHU, 9no chillers and ASHPs, extract fans, attenuators, and pumps to the roof, this had to fit in between roof steels and was very tight. The AHU was assembled, attenuators installed, and new ductwork installed to connect onto existing. The new smoke extract fans along with fire rated attenuators and ductwork we installed and connected onto existing. New chilled water pumps and inertia bases along with new pipework to route to the chillers, AHU cooling coils and existing flow and return pipework on the roof was installed and thermally insulated.

The new pipework was chemically cleaned and inhibited. A large run around coil was replaced on the Atrium extract system.

New electrical supplies were derived from the basement and pulled up to the 10th storey roof to feed the new chillers and other mech plant. New panel boards were installed on the roof, these were mounted inside 2no new GRP enclosures.

The BMS systems were modified to suit the new plant and was set to wok. All systems were commissioned including rebalancing of the floors. Temporary chilled water pipework and chillers were removed.

Our project management team which consisted of a site based mechanical contacts manager and electrical project manager, worked alongside ISG’s site management team and the site-based FM team to ensure all works sequences were communicated to all parties in advance, via the issue of progress reports, 2 week look ahead meetings, site progress and co-ordination meetings.

Programs (including a detailed commissioning program) were issued to the client for approval before the works began.
All method statements were checked by our health and safety manager and issued to the client 2 weeks in advance of any works carried out. All operatives were then required to read, sign and keep a copy of their relevant work activity RAMS. These were then reviewed periodically to ensure they were current and reflective of the works and site.

We also issued in advance our trade quality plan which sets out how we intend to manage and control the quality of the installation and materials used. This was then added to by our quality snagging and inspection reports to ensure any issues were identified and closed out.

Our quantity surveyor and commercial department worked alongside ISG’s and the project QS to ensure cost management and change control were communicated, reported and managed to ensure accurate cost reporting and negating program implications.

These processes helped to ensure that a very challenging project, both technically and logistically was completed and tested safely, on program and to the highest standards.

The management and documentation process is the same for all of our projects, with just the site and projects specifics being tailored individually for each project.