Measuring methods for determining the level of dust in the air duct.

The aim of this experiment was to compare three measuring methods to determine the level of dust in air ducts. Compared methods were a vacuum test, a tape method and an optical method. The dust samples were taken from the supply air ducts of new buildings. The paper presents and compares the results of the tests. The samples were taken from three day-care centers in the Helsinki area. The ducts were not cleaned after the manufacturing process or protected during the construction. Duct surfaces had also oil residues from the manufacturing process. The samples for each method were taken from same location. All the methods gave different results. The best correlation between the methods were found between the vacuum test and the tape method. The quality of the dust seemed to have the strongest effect on the results from the optical test method.