Mechanical services firm, Benmax Pty Ltd, had the challenging task of setting up a new mechanical room for heating and cooling systems in the basement of a heritage building almost 150 years old.

The library basement had previously been used as a storage room for books and was situated at the centre of the Arts Centre site in Christchurch, New Zealand.

With a history reaching to 1877, the Arts Centre site is a collection of 23 heritage buildings that cover a full city block.

However, the site was closed after being badly damaged in the 2011 earthquake. Today the site is part of a $NZ290 million restoration project that involves modernising site infrastructure while preserving conservation standards and ensuring buildings are earthquake resistant.

While the original schematics of the buildings will not change, services inside like heating and cooling are being retrofitted to utilise modern designs that promote sustainability, according to Benmax site supervisor, David Morley.

"The basement has a maximum ceiling height of three metres and there is only one narrow stairwell to access the room so to get large, heavy industrial components like pumps into the space we really had to get creative," he said.

Benmax comissioned the Victaulic Construction Piping Services (CPS) department to help with mechanical piping system design, and provide detailed spool drawings to prefabricate the pipework.

“Victaulic CPS provided an overall design of the heating and cooling systems in the pump room, then broke down the schematics into smaller, segmented spools that were small enough to meet the space restrictions of the site,” Morley said.

“Because access to the space was down an old stone staircase, we were limited to working in sections of pipe that were less than three metres long.

"If we had opted for a welded or flanged system, every three metres of pipe would have required welding onsite. With Victaulic, we just threw on a coupling and we were done,” Morley said.

The design of the cooling system underwent an upgrade as well. By utilising the artesian water from the natural subterranean water supply, the new system does not require cooling towers.

The system uses the constant energy from the artesian water to maintain the correct temperature in the condenser pipework.

The artesian water flows out of the bore wells, where the natural head pressure push the water six to nine metres in the air, at a constant temperature of 12°C.

Variable speed pumps ensure there is always the correct amount of water flowing through the heat exchangers according to demand. This energy (12°C) is constant and in this case is used to heat the condenser water, to prevent it from getting too cold and freezing.

“During the testing and commissioning of the systems in the library plant room, out of the hundreds of couplings installed we only had one leak due to a nicked gasket," he said.

Arts Centre site manager Chris Whitty said the new system is a great long-term solution for the site in terms of efficiency and sustainability.

“The new radiators blend sympathetically with the historic surroundings and put out a nice, quiet, gentle heat," Whitty said.

"The opportunity presented by the earthquakes allowed the Arts Centre to modernise and upgrade its systems to the equivalent of any modern build.”

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