Inverkan av värmepressning på mögelbeständighet hos granpanel
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Mould and blue stain attacks has become a growing problem in the construction industry. These attacks cause problems of various kinds. If it occurs indoors, it may cause health problems and in cases where mould is outside and fully visible problems become mainly of aesthetic nature. This thesis is a part of a TCN-project (Mould growth on sapwood boards exposed outdoors: Impact of drying process) which was conducted in 2009 at LTU Skellefteå and SP Trätek. One of the goals of the TCN-project was to reduce mould risk of tongued and grooved boards by temperature treatment. This thesis is a part of that work. The thesis consists of two parts: A.Determine whether heat pressing on the flat sides of unplaned lateral exchange of spruce has any effect on mould susceptibility. Is it possible to make the sugars at the surface and the surface itself less attractive to fungi by contact heating? The work contains the following main elements: § Scanning of wood surfaces with line camera before and after mould test § Heating experiments in veneer press § Mould test in climate chamber § Visual assessment of mould growth with self-made grading system B.Evaluation of the software MouldAnalyser 1.0. The purpose of the program is to determine percentage of mould growth in scanned RGB images of infested wood surfaces. The wood used in conducted experiments was 22x100 mm boards of spruce. The test material consisted of five 30 cm long specimens per group (=10 surfaces) and nine references (untreated). Three temperatures and three treatment times were selected for the heat pressing. Temperatures: 140°C, 170°C and 200°C Times: 1 min, 3 min and 10 min A total of 9 groups (3 times x 3 temperatures) The mould test lasted for eight weeks in a climate chamber with a relative humidity of 95 % and a temperature of 22°C. The evaluation of the mould growth was made with a four-point mould scale. Conclusions A.It is possible to make wood surfaces less attractive to mould by contact heating. All three press temperatures and two out of three (3 min and 10 min) press times resulted in significantly lower mean mould growth than the reference group. (All significant differences are at significance level 0,05). B.MouldAnalyser 1.0. + Works well when mould growth is heavy Works well with contrasty fouling Works well with homogeneous material - When mould growth is moderate, a unreasonable amount of noise occurs Wane and knots are classified as mould Sometimes veining and other surface roughnesses are classified as mould Recommended for analysis of microscopy images or other selected (homogeneous) surfaces.
Place, publisher, year, edition, pages
2011. , 64 p.
Teknik, träteknik, träfysik, värmebehandling, värmepressning, kontaktvärmning, träyta, gran, beständighet, mögeltest, mögelgradering, svampar, MouldAnalyser 1.0
IdentifiersURN: urn:nbn:se:ltu:diva-44261Local ID: 20dc34be-2fee-4b36-9b0c-a2dc14b8f4a2OAI: oai:DiVA.org:ltu-44261DiVA: diva2:1017537
Subject / course
Student thesis, at least 30 credits
Mechanical Engineering, master's level
Validerat; 20110112 (anonymous)2016-10-042016-10-04Bibliographically approved