Cleaning initiation criteria for heating, ventilation and air conditioning (HVAC) systems in non-industrial buildings

The objectives of this study are to reproduce in the laboratory different levels of cleanliness innon-porous ducts of HVAC systems, to compare a new method for sampling surface dust inducts with those methods cited in the literature, to compare the numerical evaluation methodto the visual method, and to propose objective cleaning initiation criteria. For each of thesimulated cleanliness conditions, a committee of specialists did a visual assessment based ona scale of 3, where level 1 meant normal, 2 meant above normal, and 3 meant serious.According to these assessments, the established initiation criteria correspond to 0.2 g/m forthe NADCA method, 0.3 g/m for the ASPEC method, and 0,6 g/m for the new method.These criteria are significantly different (p?0.05). Any of the surface sampling methods canbe used, insofar as the corresponding initiation criterion is used.