| Popis: |
This article presents and analyses the results of an Inter-Laboratory Test (ILT) of airflow resistivity measurements according to the ISO 9053 standard. The main result of the ILT is the determination of the repeatability and reproducibility standard deviation values typical of these measurements, for the first time since the ISO 9053 publication in 1991. Ten European laboratories took part in the ILT project; two melamine foam sheets of different thickness, taken from the same factory batch, were sent to each laboratory. The laboratories cut the test samples and carried out measurements in repeatability conditions, either on a single sample either on different samples, in order to take into account also the influence of the sample cutting and non-homogeneity of the foam. The data show that most of the laboratories have a good internal repeatability, particularly for single sample measurements. The overall reproducibility is not so good, mainly due to systematic deviations inherent in the current laboratory practice. Measurements conducted by some laboratories using different methods, in order to verify their effective equivalence, are also reported. Finally, remarks on the current measurement procedures and proposals of amendments to the ISO 9053 standard are presented. |
