PROJECT: Dac Beachcroft LLP
As we all know solicitors can sometimes get a bit hot under the collar, but non-more so than when the comfort air conditioning system fails. Indeed this was recently the case at top city lawyers DAC Beachcroft LLP. Urgent replacements were required so following a competitive tender process Artic Building Services Ltd won the contract to remove the two old 301kW R22 McQuay chillers and replace them with suitable alternatives.
Following a site validation survey to determine the primary and secondary flow rates through the existing chilled water circulation pumps and the current noise levels of the equipment, essential to satisfy the local authority building control. With the clients consent it was decided that the most suitable replacements would be Airedale Deltachill 311kW units. Not only did they match the power requirement, but the foot print of these units closely matched the original McQuay units, therefor only minimal modification to the existing supporting steel work would be required.
Preparations for the changeover of the units included de-gassing to remove the old R22 refrigerant in accordance with the current F-Gas regulations, fabrication of the extra steel supports and anti-vibration mounts and the preliminary fabrication of the new chilled water distribution pipework. The city location, with its narrow streets, posed a challenge with regard to gaining access for the crane. However, having gained permission from the City of London Corporation to close the road, the crane was positioned and the process of removing the old chillers from the roof top began. Once removed the existing system was taken to a licensed facility for recycling. Having sited the new chillers on the modified structural steel work the process of connecting the newly fabricated chilled water pipework began. The new pipes were connected to the chillers with rubber bellows situated between the pipe and the chiller to isolate and damp down any vibration. Chilled water pipes were thermally insulated with rigid glass fibre sectional lagging complete with foil faced vapour resistant coating.
Upon completion of the installation the noise levels were measured to ensure compliance with local authority building control. The primary and secondary flow rates were measured to check the system performance. Additionally during the commissioning process the system was optimised and balanced to the existing fan coil units. New BMS interface cards were installed to enable the existing Trend BMS to communicate with the chillers and water samples were sent away for analysis to ensure the correct level of corrosion inhibitor had been added to the system. Hand over to the client included operation and maintenance manuals, a set of as built drawings and full certification which included a Hazardous Waste Transfer Notice for the R22 refrigerant.