Evaluation of fluid pressures applied to the building envelope during maintenance: Fid-Bau Portal

Evaluation of fluid pressures applied to the building envelope during maintenance

Muir, Anthony / Gjerde, Morten

Maintenance of the building envelope is required by the New Zealand Building Code. Although normal maintenance is not specifically defined, the code does limit the forces that might be applied to a building as defined in AS/NZS 1170:2002, Structural Design Actions. This article reports on research that quantifies and contextualizes the pressures that are applied to the building envelope during washing. The study includes evaluation of pressures exerted by the garden hose as well as small and medium-sized water blasters that are typically used by home-owners. A prototype test rig was designed and built to measure the forces applied by the water to flat surfaces, intersections and internal corners. Measurements were recorded at various distances from the test rig. Directly relating the recorded data to the water penetration limit state, the building envelope's design limit, identifies cleaning processes that are inappropriate and breach the NZ Building Act. The results identified that some commonly performed cleaning processes may subject a building's exterior to forces significantly greater than they are tested or designed to withstand. Significantly, the greatest forces a building's envelope (its elements and details) will experience throughout its life are those applied during the cleaning of the building.