Programming of the works was of fundamental importance since the Wolfson Plant Room also provides the primary LPHW heating, domestic hot and cold-water services to a number of other prime buildings – namely the Lecture Theatre, Blue Boar Court and Whewells Court all of which are utilised throughout the year. In this respect an enabling works contract was introduced to minimise the impact of the main refurbishment works.

The enabling works included the removal of asbestos insulation, major alterations to the existing chimney flues (to ensure compatibility with modern gas fired condensing boilers), replacement of the ventilation systems providing combustion air to the boiler plant, provision of a stand-alone temporary plant room, associated builderswork, etc.

The main refurbishment works were completed over a highly concentrated twelve week working programme, indeed with much careful planning, including the offsite pre-fabrication of large sections of pipework and ancillary components the project was duly completed on time and within budget. The proof in the success of this project has been the genuine interest that the Client portrayed throughout the design and installation period; and the fact that their intrinsic pride has remained intact. Indeed, despite the complexities of the system, all of the equipment and plant continues to operate faultlessly.

Extent of Mechanical Services:

• 4 No. “300 Vitocrossal” gas fired, condensing boilers with fully modulating pressure jet burners and a combined heat output rating of 2750kW.
• Owing to the relatively high LPHW system content, in excess of 35,000ltrs, a “pressure-less volumetric expansion system” was incorporated. The volumetric expansion is controlled via an open vented cylinder containing a butyl membrane; on system heat up a bypass opens to allow direct expansion into the cylinder with excess pressure reduced by flexing of the butyl membrane. As the system cools, line-pumps transfer the water from the cylinder back into the primary circuits.
• The plant room contains a total of 22No. individually pumped circuits, with pump duties ranging from 0.75 kg/sec @ 25kPa to 14.5kg/sec@110kPa.
• The domestic cold-water services (and HWS cold feed) are fed from a pre-insulated GRP break tank, with a nominal storage capacity of 15,000ltrs. A cold-water pressure booster set complete with jockey, standby and duty pumps is capable of providing a maximum simultaneous water flow rate of 9.5ltr/sec @ 2.5 bar gauge.
• Domestic hot water is provided via 4No. unvented “Vitocell H300 indirect HWS calorifiers, each with a storage capacity of 500ltrs.
• A comprehensive Building Energy Management System, incorporating head-end supervisor and full graphics package, is provided to ensure the safe and efficient operation of all equipment. Increased energy efficiency of the plant has resulted in an average fuel saving of 35% per annum.