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Investigation of microwave as a means of eradicating dry rot attack in buildings
1992 - IRG/WP 92-1545
A microwave-apparatus developed for treatment of building-structures infested by dry rot was tested in the laboratory. The test-conditions simulated treatment of either infested timber or infested brickwork. Sawdust samples, both wet and dry, infested by viable mycelium of Serpula lacrymans were packed in glass-tubes. The tubes were then placed in the middle of either 20 cm thick wooden beams or 35 cm brickwork. The temperature during microwave-treatment was measured both in the tubes using toluene thermometers and in the "construction" using thermo-couples of the copper-constantine-type. The viability after treatment was tested by growth-ability on malt-agar, by ATP-content and by nucleus-staining. The lethal temperature with this specific apparatus was 37-39°C in brickwork and 40-50°C in wood. In comparison with more conventional methods of heat transfer microwaves seem to be more efficient. The variation in temperature within the treated area was undesirably high and in situ treatment above lethal temperature with this specific apparatus would lead to an unacceptably high risk of damage.
C Kjerulf-Jensen, A P Koch


Effects of steaming heat treatment of wood on the stimulation of termite feeding
1997 - IRG/WP 97-10212
At the 26th IRG conference, we reported that steamed Japanese larch heartwood samples were suffered a serious attack by subterranean termite, Coptotermes formosanus both in choice and no-choice feeding tests. This is possibly caused by the yield of termites stimulants in the wood samples resulting from the steaming process. Since the steaming heat treatment has often been applied to other several timber species for their drying, dimensional stabilisation, etc., attention should be paid to them on the stimulant effects of this treatment on termite attack. This paper deals with the results of choice and no choice feeding tests of termites using steamed or dry-heated samples of wood for commercial use in Japan. Some steamed wood species were heavily attacked by C. formosanus or Reticulitermes speratus while all dry-heated samples were not attacked more than unheated controls.
S Doi, Y Kurimoto, M Takahashi, T Yoshimura


Working Group I Sub-group 5 'Insects in dry wood'. Plan for data sheets
1982 - IRG/WP 1173
S Cymorek


The restricted distribution of Serpula lacrymans in Australian buildings
1989 - IRG/WP 1382
Temperature data has been gathered over a number of years, not only for flooring regions of various buildings in Melbourne, but also within roof spaces and external to the buildings. Findings are discussed in relation to the distribution of Serpula lacrymans within Australia, its restriction to certain types of building construction and its restriction to flooring regions. The subfloor spaces of badly-ventilated, masonry buildings are highlighted as being better suited than are the subfloor spaces of, for example, Japanese buildings for the activity of this fungus. Hence Serpula lacrymans is very restricted in its distribution in Australia, yet where it is active it does grow rapidly and causes rapid flooring failures.
J D Thornton


The dry rot fungus Serpula lacrymans. Examples of attack and remedial treatment
1988 - IRG/WP 1347
The film deals with several aspects of dry rot attack and eradication in buildings. The detailed biology and morphological charasteristics of the fungus are portrayed. The various forms of mycelial growth, the role of the strands in the nourishment and spread of the fungus, as well as the many types of fruitbody formation are outlined. Environmental and nutritional requirements of the fungus as well as the potential infection danger posed by the basidiospores are discussed. The second part of the film, outlining the main reasons for dry-rot attack and spread in building together with the significant damage caused, shows the full extent of the problem to expert and lay-person alike. The necessity of correct survey and inspection of decayed areas to determine the full range of attack is stressed. Examples of various remedial treatments and the present technological state of eradication techniques, e.g. pressure injection, in Germany are discussed.
G Buchwald, B M Hegarty, W Metzner, R Pospischil, H Siegmund, P Grabow


Improved techniques designed for evaluation of fungicides in soil for control of dry rot fungus Serpula lacrymans
1985 - IRG/WP 2238
Improved techniques provide a laboratory method for the evaluation of chemicals in soil for control of dry rot fungus Serpula lacrymans. Results with their application to three chemicals were reported. These techniques are useful to eliminate chemicals lacking the necessary toxicity and weatherbility for dry rot control when the chemicals have been applied to the soil.
M Takahashi, K Nishimoto


Application of radio frequency heating to accelerate fixation of CCA in treated round-wood
1999 - IRG/WP 99-40133
The potential of radio frequency heating to accelerate the fixation of chromated copper arsenate (CCA) in treated round-wood was assessed. Pre-dried Douglas-fir and western red cedar round-wood sections were pressure treated with CCA in a pilot plant retort, after which they were placed individually in a pilot radio frequency (RF) chamber. Based upon the color reaction of chromotropic acid with hexavalent chromium and the quantitative assessment using diphenyl carbazide, fixation was achieved in less than 6 hours. During heating, the temperature at various locations inside the pole sections was monitored by fiber-optic thermocouples. The moisture profiles before, and after fixation, were also recorded. Further studies will examine other benefit of RF heating, including a) sterilization, and b) rapid drying of round-wood with minimum check formation.
Fang Fang, J N R Ruddick


Insects in dry wood (other than termites)
1977 - IRG/WP 153
S Cymorek


The dry rot fungus and other fungi in houses. Part 2
1993 - IRG/WP 93-10001
J Bech-Andersen


The dry rot fungus and other fungi in houses. Part 1
1992 - IRG/WP 92-2389
J Bech-Andersen


Iron promotes decay capacity of Serpula lacrymans
1993 - IRG/WP 93-10008
The influence of iron and iron compounds on the decay capacity of Serpula lacrymans was studied. Mass losses of pine wood caused by dry rot fungus were increased when FeSO4 was added into the culture medium or when there were iron nails or stone wool on the culture medium. This supports the hypothesis that iron in stone-based building materials is one reason for the increased decay capacity of Serpula lacrymans.
L Paajanen


Working Group I 'Biological Problems' Sub-group 'Insects in dry wood (other than termites)', Scope of work
1976 - IRG/WP 152
S Cymorek


Some thoughts on the future strategy for eradicating Serpula lacrymans from a building
1989 - IRG/WP 1405
We now have a clear view of the mechanism of translocation of nutrients in the mycelium of Serpula lacrymans which is one of the physiological processes underlying the remarkable capacity of this fungus to spread through a building. Here the elements of the mechanism of translocation are dissected out to suggest avenues which might be followed in the search for new ways for eradicating the fungus from buildings.
D H Jennings


Biological performance of gypsum products containing borates
2000 - IRG/WP 00-30237
At suitable retentions borates have biostatic properties enabling them to be used for biodeterioration control in wood. They provide protection against decay fungi, mould, and termites, which are known to also attack gypsum products. Currently, many gypsum products contain added borates, which are used to improve physical and processing characteristics. Work examining the effect of borates at controlling biological attack in gypsum products is presented in this paper. Gypsum or gypsum board with different borate loadings was tested for its performance against dry rot, mould, and subterranean termites in order to see if current commercial levels of borates used in gypsum products would also render them resistant to these common types of biodeterioration. It was confirmed that the presence of borates significantly decreases the amount of biological attack found in gypsum products. From the results obtained it can be concluded that the addition of borates to gypsum products provides more than simple mechanical and processing improvements. For complete biodeterioration control however, especially against mould, higher retentions should be considered. This knowledge could have great significance in the near future, with moves to require termite resistant construction materials (including gypsum board) in some areas and the rising concern of illnesses associated with 'sick building syndrome' caused by in-house mould growth.
J L Fogel, J D Lloyd


The effectiveness test of chemicals against Serpula lacrymans
1984 - IRG/WP 2222
The effectiveness tests of wood preservatives against Serpula lacrymans were conducted in accordance with Japan Industrial Standard A 9302 and Japanese Wood Preserving Association Standard No. 1. Also, the soil treatment test against this fungus was carried out with two chemicals. The preservatives tested without Creosote oil (out of JIS) had sufficient preservative effect against Serpula lacrymans. Flutolanil for soil treatment had full effect for suppression of the hyphal growth of Serpula lacrymans onto the soil surface.
S Doi


Biological control of Serpula lacrymans using Trichoderma spp
1994 - IRG/WP 94-10069
The effectiveness, or otherwise, in killing Serpula lacrymans, of a range of Trichoderma spp. in a variety of media and using two different incubation systems has been tested. In agar based systems with normal nutrients or minimal nutrients with high or low nitrogen contents and high or low iron content Trichoderma harzianum 25 proved to be the most efficient and killing Serpula lacrymans. Other species, such as Trichoderma hamatum 150, were effective in some media but not in others. Initial observation on partially decayed small wood blocks suggested that actively growing Serpula lacrymans could not be killed by Trichoderma spp.. Experiments undertaken on a specially designed system, however, indicated that certain Trichoderma spp. can act as effective antagonists even in wood based systems.
A J Score, J W Palfreyman


Changed susceptibility of the chemically and thermally degraded spruce wood to its attack by the dry rot fungus Serpula lacrymans
1999 - IRG/WP 99-10322
In buildings, some intentional or unintended situations can occur at which some wood products are exposed to aggressive chemicals and also to higher temperatures. Occasional activity of fungi on such pre-attacked wood products can be either higher or lower. This paper deals with changes in the susceptibility of spruce wood (Picea abies L. Karst.) to attack by the dry rot fungus Serpula lacrymans, in such situations, when the wood samples 8.5x8.5x120 mm3 (RxTxL) were first pre-treated with 1% water solutions of selected acids (H2SO4, CH3COOH), bases (NaOH, NH4OH) or oxidizing agent (H2O2), or they were also exposed to a higher temperature (190°C/3h). The activity of S. lacrymans was totally restricted only in one situation, if the wood was pre-treated with sulphuric acid and then exposed to 190°C. On the other hand, specimens pre-treated with ammonium hydroxide were more susceptible to bio-attack (in both situations: without or with high temperature pre-treatment effect) than sound ones.
L Reinprecht


On the problem "House Longhorn Beetle" in hardwoods and an aid to distinguish between Hylotrypes bajulus and Hesperophanes cinereus larvae
1981 - IRG/WP 1141
S Cymorek


The true dry rot fungus (Serpula lacrymans) found in the wild in the forests of the Himalayas
1993 - IRG/WP 93-10002
J Bech-Andersen, S A Elborne, F Goldie, J Singh, B Walker


The effect of temperature on the rate of fixation of an alkyl ammonium compound (AAC) wood preservative
1984 - IRG/WP 3293
The rate of fixation of an alkyl ammonium compound wood preservative was measured by soaking samples of wood wool in various preparations of the preservative for arbitrary times followed by immediate leaching in water. The wood wool was then analysed for residual preservative. The results indicated that fixation was very rapid and increased at higher temperatures.
P Vinden


The dry rot fungus and other fungi in houses. Part 3
1994 - IRG/WP 94-10083
J Bech-Andersen


List of Members of IRG and contributing workers proposed for membership in IRG/WP/ - I - Sub-group 5
1976 - IRG/WP 154
S Cymorek


Theoretical and practical experiments with eradication of the dry rot fungus by means of microwaves
1992 - IRG/WP 92-1577
Engineer Claus Andersen constructed a device in 1986 for microwave treatment of fungal infested timber. The device was tested on ampullae with live fungal mycelium of the dry rot fungus. A 10 minutes treatment at 37°C gave satisfactory eradicating effect. The method has since been used in practice in approximately 100 instances. A spot-test control has shown satisfactory results.
J Bech-Andersen, C Andersen


TBTO absorption and penetration in pine joinery treated by various processes
1989 - IRG/WP 3523
Matched sections of several White pine (Pinus strobus) and Ponderosa pine (Pinus ponderosa) mouldings were treated with TBTO by Double vacuum, modified empty-cell, 15 second dip and several preheating treatments followed by a 15 s dip treatments. As expected the double vacuum and empty-cell (batch) treatments resulted in much greater retentions and penetrations than the dip treatments. The absorptions by the 15 s dip treatments could be improved significantly by preheating the wood to 60-90C° by microwave, radio-frequency or infra-red techniques. Since this approach is amenable to a continuous treatment process, it is being evaluated for potential commercial application.
P A Cooper, Y T Ung


Quality control of microwave treatment of timber after dry rot attack
2001 - IRG/WP 01-40205
In Denmark microwave treatment of timber has been used during the last 15 years for eradication of dry rot (Serpula lacrymans). About 1500 microwave treatments have been employed in coorporation with Hussvamp Laboratoriet. Previously all the infected timber was removed plus an extra metre as a safety zone. This meant that all casting boards and plaster had to be removed as well and joists replaced. The cost of such a replacement would often amount to several thousand Danish kroner (100 Dkr . 14 Euro). In cases with sufficient residual strenght of infected timber the cost can be reduced by 40-50% with microwave treatment. Very often it is necessary to support the construction with a fishplate of pressure impregnated wood. Theoretically the lethal temperature for mycelia of Serpula lacrymans is 37°C during 10 minutes, but to ensure that also resting mycelia are killed a temperature of 75°C is used. In order to ensure a sufficient quality of the treatment a thermo controll method has been developed by Hussvamp Laboratoriet whereby the temperature reached inside the wood is registred. In a joist a hole with a diameter of 13 mm is drilled from the side to the centre. A TERMAX or RS 285-936 irreversible temperature sensitive label is placed inside a piece of plastic tube, 6 cm long and 12 mm across, which is inserted into the hole. This is then closed with a corkplug with a diameter of 14 mm and 22 mm long. Afterwards the plug is sealed with a label carrying the logo of Hussvamp Laboratoriet and the text 'Hussvamp Laboratoriets Termokontrol'. The thermo control can be employed at the same time as the attack is delimited or at the start of repair work. After the microwave treatment the seal is removed and the corkplug is pulled out with a corkscrew. The tube with the temperature label is pulled out with a pair of tweezers. On the label the white markings turn black when the indicated temperature is reached. The markings for 65°C, 71°C and 77°C should be black in order to approve the microwave treatment. The method can also be used for other kinds of heat treatment of timber.
J Bech-Andersen, J Andreasson, S A Elborne


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