Heating-, ventilating- and air-conditioning (HVAC) components are most often made of galvanised sheet metal, which needs corrosion protection to avoid oxidation of the zinc surfaces during storage and transport from the factory. Traditionally, oils are used for corrosion protection just before the final rolling of the sheet metal, which form a sticky layer on the surface decreasing cleanliness and hygiene of the manufactured components. The manufacture of components with sharp bends or turns necessitates lubrication to decrease friction between machine tools and sheet metal, a part of which remains as a thin layer on the interior surface where it increases dust accumulation on the surface and serves as a potential growth medium for microbes. Evaporation of hydrocarbons from these oil residues decreases the perceived quality of the air, which passes through a dirty ventilation system. The quality control of the surfaces requires some kind of oil analysis. Information about the amount of oil on the HVAC components is needed by designers and building contractors who are seeking clean and odour-free HVAC systems to ensure a high indoor air quality in their buildings.
The aim of this study was to develop a consistent method for determination of the concentration of corrosion protection oils and lubricants on the surface of the HVAC components. Three different sampling methods (two swabbing methods and a filter contact method) were developed, tested in the laboratory and applied in the field. 14 refs.