Evaluation of the pressure fluids apply to a building envelope during maintenance
Authors: Muir, A.; Gjerde, M.
The aim of this research is to quantify the pressures that are applied to the building envelope during washing. This study includes evaluation of a garden hose, as well as small and medium size water blasters typically used by a homeowner. Normal Maintenance of a building is mandatory for all building owners, and is one part of a building’s Intended Use as defined by the New Zealand Building Code (NZBC). Normal Maintenance is not specifically defined but has a limit; a maximum permitted force, defined by the NZBC and AS/NZS 1170:2002 Structural Design actions. This Limit State is the maximum force applied during the water penetration test. 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 envelopes design limit, identifies cleaning processes that are inappropriate and breach NZ Building Act. 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 force a building’s envelope, its elements and details, will experience throughout its life are those applied during the cleaning of the building.