June 24, 2024 in Advisory Notes
Mould in Buildings and HVAC Systems
Mould plays an important role in the natural environment as a break-down mechanism for dead organic matter. In the built environment, it is an unwante...
235 Pyrmont Street, Sydney
Prefabrication makes the difference in Mechanical Services revitalisation. The extensive use of prefabricated services modules by A.G. Coombs in this project emphasises once again the benefits of offsite fabrication particularly during the uncertain time of COVID-19.
The mechanical services at 235 Pyrmont St, Sydney, built circa 1906, has been maintained by A.G. Coombs for a number of years. With the existing base building open-circuit condenser water cooling plant approaching end of life
A.G. Coombs was successful in tendering for a design and construct Head Contractor role direct to the owner Kador Group to revitalise the mechanical services.
The project included a new chiller and boiler plant on the roof and progressive works over several years to replace the existing condenser water system. With the building levels converted to the new cooling and heating system in stages the projects end goal was to have the building’s mechanical services at a standard compliant with the requirements of the Property Council of Australia’s ‘A’ Grade level.
The tender included a number of Value Engineered elements that reduced the project costs and improved energy efficiency. Additionally, project delivery risks were reduced site safety enhanced by using the A.G. Coombs Group’s experience and proven track record in delivering Building Information Model enabled Prefabrication to deliver a drop in, offsite assembled, rooftop plantroom.
A 3D point cloud scan was taken of the rooftop along with the floor-by-floor services, effectively digitising the project environment. This enabled timely mobilisation of the project’s early work, and as COVID-19 related lockdowns were subsequently put in place restricting site access, the virtual building model enabled the remainder of the design development and documentation process to proceed unheeded. This was crucial to the success of the project.
An early key project milestone was documentation of the works for lodgement of the Development Application to obtain a Construction Certificate. As the façade and roofline of the building were being modified an architect was engaged to develop plans to match the Value Improved mechanical design.
The design for the modular plantroom was completed during the Development Application process and off-site fabrication commenced well ahead of the scheduled site start date. The three 6m x 3m plantroom modules were completed and craned into place shortly after the Development Application was approved and before COVID-19 access restrictions were imposed.
The digitised construction model of the building was used to determine builders work set outs for pipe supports, equipment plinths, new wall locations, new floor waste and skid plinths. The model parameters were downloaded to a Trimble Robotic Total Station (RTS) that was used laser to set out the work with an accuracy of 2mm. The use of the model and digital tools for this time-consuming work significantly reduced the time required and the risk of error.
The use of A.G. Coombs BIM enabled prefabrication approach enabled the rooftop installation of 2 chillers, 3 cooling towers, 12 pumps, 3 expansion tanks, 2 Heat Exchangers and 80% of the required pipework, all in a matter of days. It de-risked the project in a number of ways, including program uncertainly with the timing of Council approvals and avoided the significant delays that would have been caused due to COVID-19 access restrictions.
