QBE House formerly known as Mt Newman House at 200 St Georges Terrace Perth is over forty years old. The building is a twenty-story building with the main air-conditioning plant located on the top two floors.
The owners of the building, the Perth Diocesan Trust, recently decided to refurbish and upgrade the Airconditioning and Mechanical services within the premises to modernise the building and bring it up to, or exceed, current market requirements. The existing airconditioning system was a “constant volume central plant system” with large Trane water chillers and existing gas-fired boilers that had been converted from diesel to gas some 15 years previously. The conditioned air was reticulated from large centrifugal fans and built up air handling units located on the 19th and 20th floors.
Norman Disney and Young were engaged to modify the system design and document the proposed changes that would bring the air conditioning system into the 21st Century and achieve a NABERS rating required to attract tenants to the building. The documented changes included a full upgrade of the airconditioning system with an occupancy of the building being 75% at the time, but fluctuating up to 1005 on completion as floors were completed and leased. This required a high degree of flexibility and the engagement of a specialist mechanical services contractor that had the skills and ability to undertake the works without impacting on the tenants daily business.
AMS were successful in securing the works and began planning with CBRE and NDY to implement the changes in stages causing minimal disruption to the paying occupants. Working with control companies, AMS's highly skilled technicians can fine tune plant operation to fine tune operations.
Floor Air Distribution
— Each floor was converted from constant volume with zone reheat to variable air volume with individual heating coils at the variable volume boxes.
— The existing return air fire dampers were replaced with new motorised fire dampers.
— The existing flexible ducting was replaced and the main branch ducting modified to suit the new design.
— All diffusion equipment was converted to swirl diffusion in keeping with current day design.
— The building BMCS system was fully upgraded to an Alerton controls system.
— The heating water pipe work was replaced and upgraded.
— All of the tenants ancillary water sourced air conditioning systems were converted to a closed loop condenser water system.
All of this work was undertaken after normal working hours and with minimal disruption to the occupants daily work requirements. Demolition of redundant equipment was removed from the building overnight prior to occupancy in the day. Installation of new pipe work ductwork, variable volume boxes and diffusion was also completed at night without effecting tenant working conditions.
Air Handling Unit Refurbishment
The existing air handling units are built up systems with Centrifugal supply air fans and Axial return air fans. There are four existing air handling units and all needed considerable refurbishment and upgrade to ensure their longevity.
All motors were replaced and installed with new speed drives, all fan bearings and pulleys were replaced. All of the chilled water cooling coils were replaced with new heat exchange coils. Insulation was replaced and upgraded.
Drain lines were improved and modified.
The existing Trane chillers weighing 22 tonnes were disassembled and removed from the building by hand after normal working hours. Existing pipe work and electrical cabinets were removed and replaced with new equipment.
Three new Smardt Chillers were assembled and installed within the plant room on the 19th floor. The building maintained conditions on all working days whilst this occurred. New chilled and condenser water pumps were installed and commissioned without any disruption to the building cooling. All new pumps were fitted with speed drives for optimum energy performance.
The existing heating water system had older style cast iron boilers and gas burners, these were upgraded with Tomlinson / Bosch systems that are engineered to reduce gas consumption to approximately 60% of the consumption of the older style system. The existing sectional cast iron boilers had to be disassembled and broken down for removal from the building. The new boilers were transported in pieces and assembled in the 20th floor plant room. Existing hot water pumps were replaced with new pumps and speed drives. They were commissioned and placed in service. All of the new equipment is controlled by the same Alerton controls system.
The existing Heating Water and condenser water riser have been upgraded with new pipe work insulation and valves. This work occurred within the riser from the 20th floor to the St Georges terrace level. The new riser pipe work has been tied into the floor pipe work on completion of the riser works with no inconvenience to the occupants or their equipment.
Essential Services: Fire Panel
Whilst new fire dampers have been installed, the existing fire panel with the mechanical services have also been upgraded and modified to ensure building complies with the current Australian Standards the fire code requirement.
This has been tested commissioned and placed in service with a full recommissioning of the fire services.
Red Brick Building - St Georges Terrace
At the front of QBE there is a historical Cloisters building currently occupied by interior designers and an art gallery. The existing airconditioning was being provided by the main Cooling plant on the 19th floor of the QBE building, it became necessary to remove this from the QBE building and provide a “standalone” chiller for this building. This initiative will ensure both buildings are able to operate independently and efficiently.
The Building will be controlled by the same Alerton Control system.
The substantial mechanical services improvements will enable the building to now be commissioned and tuned to ensure that energy efficiency is provided for the occupants and building owners. This will mean that the building, that is in a sought after location, will give tenants the modern and flexible systems offered by new buildings.
Both Norman Disney & Young and CBRE are expecting a much improved NABERS rating in the near future and congratulate the owners in having the vision and trust to improve the building green foot print through its foresight and conviction to improve 200 St Georges Terrace for its clients.