825 Method development for mold testing of wood - prestudy

Published: 28 August 2012

The purpose of this study is to develop simple and robust forced mold testing in small scale laboratory tests that can be monitored and evaluated continuously in the research projects.

Area: Durability of wood
Budget: 392 000 SEK
Duration: december 2011-October 2012
Project: Margot Sehlstedt-Persson, LTU

Background

Natural resistance to mold and rot in wood products is a crucial issue for the future use of wood as a competitive construction materials. In a recent study of moisture damage in Swedish households conducted by the Swedish National Board of Housing reported no less than 21% have problems with mold in unheated attics (National Board of Housing, 2010). If weather conditions are favorable for mold growth visible mold can occur after only a few months of use, i.e. in unheated spaces carport and storage (Nilsson and Samuelson, 2006). The changing climate with warmer and weather conditions favor mold growth on wood but the risk of the occurrence of mold growth also depends on the geographical location and the local climate (Häglund et al., 2010).

To determine the propensity of mold on building materials different kinds of short term laboratory tests are often used. There is no standardized method for determining mold growth used by all laboratories, the methods often differ quite a lot from each other. An example is spontaneous growth or inoculation of different numbers and types of sponges, sample size, climate test, the scale for the assessment of mold growth, use of a microscope or a solely visual examination in the evaluation of mold level, thresholding the digital images of moldy surfaces mm.

Purpose, objectives and boundaries

The purpose of this study is to develop simple and robust forced mold testing methods in small scale laboratory tests that can be monitored and evaluated continuously in the research conducted. The tests are conducted in climate chambers and climate boxes indoors based on natural contamination and climate choices that benefit mold growth.


The methods planned to be developed in the study does not claim to offer comparisons with other more established methods, but only comparisons within the batches included in the materials and process variables being studied.


The projects conducted within the area durability of wood includes studies where process parameters and material variables of  importance for natural mold resistance of wood studied. The processes are wood drying, heat treatment and impregnation.


Experience from previous projects is that proximity to the sample material outlet, experimental design and proximity and transparency of processes and evaluation methods used in the research give invaluable learning experiences and conclusions. The primary goal is that these simple and robust mold testing methods - regardless of the season, are possible to  be continuously evaluated in comparative studies of screening character to get relatively quick responses / indications of the impact of the process and material variables studied.


These mold testing will be done in climate chambers, controlled environment and is therefore independent of the season as opposed to the forced outdoor experiments described above.

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Final Report