Precision of Fungal Resistance Test Method for Cereal Husk-Reinforced Composite Construction Profiles Considering Mycelium Removal Techniques

Many test methods used in the assessment of construction products are characterised by poor precision, which is reflected in the discrepancies of results obtained by different laboratories. The test procedure for fungal resistance of natural particle-reinforced composite construction profiles has not been fully specified, which may lead to such discrepancies and erroneous utility assessment. In this study, the precision of the method and the influence of the mycelium removal on the fungal resistance were assessed based on the flexural strength and modulus of elasticity test results obtained for millet- and oat husk-reinforced PVC composites exposed to Coniophora puteana. The study revealed low precision of the test method, the coefficient of variation, in which, based on the standard deviation of interlaboratory reproducibility for one of the tested composites, was even higher than 20%. Additionally, it was found that the method of mycelium removal can significantly (at the level of 16% difference between flexural strength results) affect the resistance test results. This indicates the need to modify the test method and clearly specify the recommended method of cleaning samples after exposure to fungi.