Context 159 - May 2019

C O N T E X T 1 5 9 : M A Y 2 0 1 9 33 The exterior and (below) the circular stair documents. These present decisions clearly in a way that facilitates client decision-making at the project board. The project encompasses a wide range of con- siderations and interventions, from the macro- scale of public realm design, to small sections of unique decorative paintwork. An important area of work within this ambitious project is the upgrading of building services; in particular, accommodating plant and distributing services throughout the building sensitively. Such an ambitious project requires the effec- tive collaboration of experts and specialists, and a clear, methodology for conserving or enhancing the Town Hall’s heritage values. To enable a heritage-led, transparent and collab- orative approach, Purcell developed a formalised heritage engagement and assessment strategy. This established an engagement strategy for stakeholders, and a robust methodology for assessing significance and the impact of change. Historic England and the Victorian Society have been actively engaged throughout the process. At the heart of the heritage methodology is the consideration of significance: what it means for the building, and how to identify the rela- tive significance of individual aspects. Such a bespoke approach enabled significance to be consistently analysed and recorded within the BIM. It also enabled the significance of the original building services to be properly understood. In this case, the significance lay principally in Alfred Waterhouse’s well-designed distribution of services from the lowest level of the building upwards, and distributing horizon- tally through a combination of perimeter routes and grill-covered runs in the corridors. Heat was also provided through heating coils at the base of the open circular stairs, distributing heat and air Opposite: the foyer to the Great Hall and life-cycle costing into the early design stages. Being situated in the Grade I listed building enables a more widespread appreciation of the heritage significance across the team. Junior architects, graduate engineers and design lead- ers all ground their proposals in the established heritage principles. Purcell’s heritage consultants and conservation architects have led informal CPD inclusive to the entire project team, ensur- ing that the process of heritage significance and impact assessment is understood. As the project team navigates through the gov- ernance processes of a large-scale civic project, collaboration in our reporting styles has been vital. Although all disciplines carried out report- ing in the usual RIBA methods, collaborative stage reports are produced, acting as summary