Your search resulted in 93 documents. Displaying 25 entries per page.
Microbiological degradation of wooden piles in building foundations
1988 - IRG/WP 1370
White rot, soft rot and bacterial attack have been detected in softwood piles under buildings. In some cases bacteria were found to be the main degradation organisms in the studied piles. The water content of degraded piles was very high. The compression strength was quite low also in the piles deteriorated by bacteria. The density of wood was very variable, and the degree of degradation could not be evaluated according to density analyses.
L Paajanen, H Viitanen
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
An evaluation method for less termite attack execution on thermal insulation for fundation walls
2002 - IRG/WP 02-20245
According to the results by the real scale Japanese building tests, the termite installation was observed at very little spaces between foundation and insulation. The termite penetration spaces between foundation and insulation on foundation systems in Japanese wooden houses were checked by the way of streaming speed of colored water. Because of difficulty for its execution, the parts of outside angles and reentrant angles in continuous foundation were more sensitive for the termite penetration. Special accessories of thermal insulation for these angles can be effective for lesser termite installation.
K Suzuki, Y Tanaka
Problem of the treatment of dried sawn spruce building timbers with water-borne preservatives. Interim reports for discussion at the 4th Annual Meeting in West Berlin on 27 October 1972
1972 - IRG/WP 311
One of the most difficult technical problems facing the preservation industry is how to improve the treatment of refractory species of timber such as spruce. Its resistance to penetration, even under pressure' precludes its use for more hazardous service situations, and even in less severe conditions a higher level of treatment would be desirable. The importance of this subject led us to look once again at possible ways of improving treatment.
W Liese, J W W Morgan, T Hof, R O Ullevålseter
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
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
The influence of building design on wood decay
2000 - IRG/WP 00-10339
The cheapest and most effective way to prevent wood decay is to KEEP THE WOOD DRY! You and I know that, but we often forget and attempt a preservative solution to a problem better solved with good design and construction. It's also the answer to a frequently missed exam question in my Architecture class. Just as caulking is a poor substitute for proper design, so preservative treatment should be the last resort in an exposure problem, because, what if the treatment fails? Are we in a position to guarantee that every stick we treat will give "life-of-the structure" performance? "All wood rots in time," and "I won't use treated wood because the incisions are ugly," are just two statements I often hear from designers which indicate the uphill battle we have to get designers and builders to use wood properly. Substituting treatment for better design and then providing ineffective treatment have created a lack of trust of treated products among designers and lack of understanding of wood has prevented the creation of good design fixes. "Why should I pay more for treated wood, it doesn't last any longer than the untreated" a Hawaiian contractor told me; he bought thick slabs of Douglas-fir, treated green with CCA, cut them to length in the field, and placed them directly on the ground as a stairway. He was right; Formosan termites gobbled them up in a matter of months. Wrong material, wrong treatment, wrong application! Other case studies will be presented which illustrate situations where use of treated wood was perhaps not the best solution to exposure problems in structures. Prosecuted for murder for allowing the deck on your rental apartment building to decay?--you will see that one, too. (The following text is a transcription of a lecture presented from slides) I am honored to have been asked to address this meeting of the IRG. I was particularly gratified when asked to present a talk on the general subject covered by my title, which I interpreted as dealing with decay situations where pressure treatment may not be the solution of first choice. As most of you know, preservative treatment is not my field; my field is the diagnosis and evaluation of early stages of decay and the improvement of the performance of wood in structures by proper use and design. I get involved, after the fact, in trying to determine why buildings, or parts of them, have failed. But I am not a designer. I am not in a position to show you drawings which tell you how to do it right, although I'm afraid that is what the organizers really wanted from me. Also, no one asks me out to structures that are performing well; I never get to see the good ones! So, I will start by trying to discuss general principles of design which may control performance of wood in structures, but will move very quickly into performance issues which I know more about. The goal of exterior skin design for wooden buildings can be summarized by adapting a borrowed phrase with the anagram of KIDS--keep it dry, stupid! Dry wood can never decay! With the possible exception of particulate wood products, most building materials intended for exterior exposure perform well enough and are assembled with enough redundancy that how they are put together usually is the most important criterion in their performance. The controlling factors usually are minute details. An example is this roof-wall intersection, where the vertical membrane ran underneath the roof membrane, allowing rain water to gather underneath the roof covering. This, probably, was a result of a simple error in scheduling the building trades--the workers installing the wall membranes came on site before the roofers. All exterior design should be focused on shingling of intersecting materials so that water is constantly being shed outward, away from the structure. In the U.S. the major uses of treated products are in utility poles and railroad ties (sleepers to the Commonwealth). These products are purchased by sophisticated buyers who know what they want, what the treating industry can produce (and even sit with them on the committees which establish the treatment standards), and they get what they want--a long-lived product. In my view, the performance problems are primarily in the consumer area where the typical user knows very little about what they want and how to use it, and can't tell the difference between a good product and a bad one. In this area quality control and certification become important, and I'll talk more about that area toward the end. I do, however, have two examples from the consumer/structural arena where pressure-treated wood is being asked to perform unusual duties and is expected to perform well. It's hard to think of a structure being asked to perform under conditions of greater decay hazard than a houseboat. Here the architect used pressure-treated redwood siding to try to weather the extreme conditions of the Sausalito, California waterfront, and then liked the patina of the Chemonite treatment so much that he had the large structural and decorative members painted to match. This is a quite attractive effect which is, to the best of my knowledge, performing well. A "work in progress" is the restoration of a historic structure, the San Francisco Conservatory of Flowers. This structure is scheduled to be demolished, piece by piece, with all of the thousands of pieces of glass retained and the thousands of pieces of old-growth redwood holding them up replaced with exact duplicates made of young-growth redwood through-treated with Chemonite. I have every confidence that this solution, the only reasonable solution we could come up with for a historic structure, will perform superbly, while maintaining the historic fabric and composition of this unique structure. Now on to the area where I have more experience! I don't know about other regions, but wooden deck failures are becoming increasingly important in the Western U.S. Over the last several decades, our drive for quality outdoor living has converted decks from small, temporary attachments to our homes to large, important portions of the structure, expected to have the same performance life as the rest of the structure. Decks are, by definition, outside the protective building envelope and serve in much more decay-conducive environments than most of the rest of the structure, with the possible exception of the roof which is specifically designed to shed the elements. Decks are not. With decks going higher into the air, their failure increasingly involves human injury. The most absurd of such an instance of which I am aware was a deck in San Francisco on a Victorian structure which was being used as rental apartments. This truly was a tragic incident because failure of the deck killed a woman, but it was made more tragic by an overzealous, headline-seeking, District Attorney who decided to prosecute the owner of this building for murder! Now that would certainly do something for quality control in the treating industry if a product failure could lead to criminal prosecution for murder. But this was not treated wood. Should it have been? This is a three-story, Victorian building in a major, high-class, residential area of San Francisco. With this sort of view, you can see why this is a prized place to live, and why decks are popular. This building used to have a third-floor rear deck, attached to the structure at the U-shaped marking beneath the sliding glass door. From talking to the renter of that apartment I learned that he had invited a wedding party to his apartment for the reception. It was a nice day so most everyone was out on the deck. At one point he gathered everyone together for a group picture. Everyone lined up against the outboard handrail, with a spectacular view in the background, for the group picture. The apartment renter, who was near the sliding glass door with the camera, reported hearing a loud snap and, feeling the back of the deck rising, jumped through the open sliding glass door into the apartment. He looked back in horror to see the deck tip forward, hit the second floor deck and bounce, causing it to rotate 90 degrees and flip upside-down on the concrete covered back yard. A number of the guests received serious injuries when they hit the concrete, but one unfortunate woman, most tragically the new bride, ended up underneath the deck and was killed instantly. The headlines the next day touted the negligence of the building owner for allowing his deck to rot, thereby causing this accident. I was called to the site, a seriously unnerving experience, by the attorneys representing the bride's estate in civil court to document the role of decay in causing the failure. But I could not, making me persona non grata because I disagreed with the conventional wisdom carrying forward the case and was never asked to do anything more on it. Let's look at how I came to my unpopular conclusion that decay was not the cause of this accident. This was a 40 or 45-year-old, untreated Douglas-fir deck, not at all an uncommon situation in the San Francisco Bay Area. Certainly, some decay was present, as expected, and there was evidence that decayed members had been replaced from time to time in the life of the structure. There was a good deal of decay in the outboard ends of the stringers, to which the handrail had been attached. If failure of the handrail had been the cause of the injuries, I would have agreed that decay was a culprit. But it was not--the handrail broke on the way down. At the back edge of the deck, where it attached to the wall, the stringers appeared to butt directly to V-rustic siding while sitting on a 2" ledger, with blocking toe-nailed into the stringers and face-nailed into the siding. Portions of the blocking had been replaced with plywood, apparently as a repair for decayed wood. Also visible in this area are relatively new, as yet unpainted, standard joist hangers. These would have been face-nailed into the blocking and the stringers. Now lets focus on the SECOND floor deck, of similar construction. The stringers rest on a ledger, too, but here the joist hangers have so-called "hurricane tabs" which firmly attach the rear of the deck to the ledger. Looking again at the ledger for the third floor deck, we see that it, too, used to have hurricane tabs, but they were removed sometime since the building was given its current coat of paint. Also notice that the failed deck no longer has these tie-downs. This configuration made the third floor deck very vulnerable to pulling away from the wall, which the second floor deck could not do, unless the ledger itself pulled off the building. The third floor deck was supported by a full-width beam placed a considerable distance back from the handrail edge. Again, looking beneath the SECOND floor deck, we see that it, too, had that construction, but that someone had moved the beam outward, toward the handrail, since the last painting, making it more stable to excessive weight applied at the outboard edge. My reconstruction of the failure was that the heavy load of the wedding party having their picture taken against the handrail caused the handrail edge to bend downward, applying an upward force to the back end of the deck, which no longer was tied to the ledger, causing it to pull the face nails and lift off the ledger. Now unstable and rotating about the single support beam, the deck tilted forward, the rear hitting the second floor deck causing it to bounce and flip over. It probably hit at an angle, causing the 90 degree rotation, because the guests were collected at one corner of the handrail for a better background view. The cause of this tragedy was not the fact that 40-year-old untreated decks have decay in them, it was the result of someone, during a repair, substituting standard joist hangers for the original ones with tie-downs at the deck's connection to the building, and the failure to move the support beam further toward the outboard edge of the deck, as had been done for the second floor deck. I don't like personal injury cases to begin with, and I can tell you I hope I never have another failure case where the pieces are adorned with flowers. But the point I want to make in sharing this with you is that the solution to this problem is NOT the use of pressure-treated wood. Parenthetically, it also is not murder! Another deck problem I have encountered involves a design feature called "mill construction." This involves Douglas-fir 2x6 or 2x8s on edge, nail-laminated together. The architects tell me that this system was developed on the then-timber-rich West Coast of the U.S. during WWII, when the Federal Government had sequestered all construction steel. This approach allowed the construction of long-span industrial floors of wood, without the need for steel to stiffen them. There is no reason to use mill construction today; in fact, because it is so wasteful of wood, there is good reason NOT to use it. It is totally inappropriate in residential construction, where such massive strength is unnecessary, and, because of all the capillary spaces between laminates, should never be placed in exterior exposure. In this case, a deck was created by simply making the laminates in this area about six feet longer. Since there was no roof overhang, the only protection for this assembly was a coating of "miracle goop." These all fail eventually leading to a severe decay problem in this mill construction deck. Because of the capillary spaces, the decay progressed back into the building and down into the glulam beam holding up the downhill side of the building. Again, the solution to this problem is NOT pressure-treated wood. This, simply, is a stupid design which should never be used in residential construction, especially in exterior exposure. Now, here's a deck that's a challenge! We've got a lot of steep, very valuable, land overlooking the Pacific Ocean in California, which tempts people to do things like this. Does anyone want to take on responsibility for the treatment of the wood holding up that deck, especially in light of the criminal prosecution in San Francisco? Which brings up the issue of quality control for treated wood entering the consumer market. These data are old, now, but they were produced from a sampling of retail-end lumber which contained a brand by a third-party agency guaranteeing that this lumber met their specifications. Unfortunately, commercial politics destroyed even this agency in the U.S., so there is no organized, even partially reliable, third-party inspection quality assurance available to retail consumers in the U.S. We can not expect builders to rely on treated products if we can't even meet our own minimum standards a majority, let alone approaching 100%, of the time. This is a foundation piling, driven into muck soil to support a structure. The non-green patches are where bark was still present during treating and has sloughed off after drying in place, leaving untreated wood. Even where it is green, the penetration was less than 1/8-inch. The tragedy here is that there are actually over 400 such piles, holding up an 80-unit condominium structure, with no way to replace them. The solution to this problem would have been properly pressure-treated pilings, but, without quality control, that didn't happen. Here is a stack of 6x14, Douglas-fir beams, treated with Chemonite. This shows a pretty good representation of the difficulty of treating sawn Douglas-fir. The problem here is not the quality of treatment (that's actually pretty good for sawn Douglas-fir), the problem is that the designer ordered the beams in the wrong length, requiring that they all be cut to length in the field, exposing the untreated wood you expect at the center. Here, treated wood was the recognized solution, but the end-user messed it up. The developer of this project in Kailua, on Oahu, told me at a seminar in the early eighties that there was no point in paying extra for treated wood because it didn't last any longer than untreated wood. Granted, at that time Hawaii was treating green, sawn Douglas-fir with CCA and calling it "treated" under a "Hawaii use only" u32 ?stamp. Still, I jumped at his invitation to see his experience, and this is what I found. The roof of the garages was sodded--a challenge for wood anywhere, but particularly in Formosan termite country. And for the stairways, he was using 3 or 4-inch-thick slabs of sawn Douglas-fir, cut to length in the field, and placed directly on the ground. He was already replacing rotten and termite-eaten treads less than two years into their service life. Maybe you could get away with this with adequately treated wood, but why try? And you certainly won't be successful when the treated wood you're using has penetration like this! Glulams in exterior exposure present a special problem. Most made-up members are too large to treat and, with woods like Douglas-fir where penetration only to the depth of the incisions can be expected, this is clearly not a solution. Treating the laminates also is problematic, not just because of possible effects on gluing, but, in California, the shavings were declared by the State regulators to be a Class I toxic waste. The laminators got rid of their treated wood in a hurry! This project used glulam for nearly everything on the outside of the buildings--through-members protruded beyond the building envelope, blocking and rim-joists were glulam with the sides exposed, they even designed glulam "stubs" to make it look like the beams crossed over the columns. The solution to this problem is NOT pressure treatment. This, again, is simply a matter of stupid design! In fact, because of their innate nature, glulams simply are not members that should be in exterior exposure. Examination of this end, with the various grain orientations of the different laminates, shows that, if this beam were to undergo any significant moisture content cycling, it would develop up-facing checks deep down into the beam, directing water into the center of the member where it becomes trapped and facilitates internal decay. These are solid wood "flying" beams, penetrating the walls on both sides and impossible to flash or caulk successfully because of all of the potential for movement, therefore decaying and leading the decay into each structure. Pressure treatment is not the solution to this problem, this is simply another dumb use of wood. I'm not sure that our fire codes allow this anymore, anyway. I have heard it said by a number of architects that, usually, caulking is simply a dsigner's poor excuse for proper design. Even if it doesn't leak, it creates a lasting, constant maintenance problem for the building maintainer. These examples led to wood decay, but, again, treatment was not the solution. No amount of treatment could overcome the problems caused by this misapplication of grooved plywood siding and scarf-jointed battens. Grooved plywood should never be applied with the grooves horizontal, because it causes up-facing cracks into the center of the panel at the edge of each groove and the groove acts like a gutter directing water to the joint between panels. A properly assembled scarf joint sheds water back to the surface of the two joined pieces, while these reverse scarfs draw water in to the exact location the battens were put on to protect. This is the only case I've ever seen of mushrooms growing directly out of building siding, but treatment would not have helped this either. The siding leaked water into a wall filled with insulation which was, essentially, crushed newspaper, which provided both the moisture and carbon source to support extensive decay. Playground equipment! I've lost track of the number of calls I've gotten from parents asking for a "non-toxic" preservative for the playground equipment their children play on. No matter how you start trying to answer that question, you lose them quickly. This is the equipment my kids played on and I always took the position that I would rather risk their eating a little chemical than running the risk of having one of these huge members decay and come down on their head. Here treatment should be the solution but, because of chemophobic parents, it will only be a workable solution if we can develop deep penetration with that elusive "non-toxic" preservative. Actually, that is what happened with this playground equipment (unfortunately, the "come down on their head" part). The parents club got a number of old 12x12s--former excavation shoring, which had been stored solid-piled on the ground for a number of years. They buried one end in the ground, creating a Stonehenge-like circle of uprights. They fastened eye-bolts to the top of these, now, vertical cantilever members, attached chains which were threaded through old tires, producing a creative, undulating, play surface. Alertness during the construction process would have revealed that these members were badly decayed, as the stack of washers penetrating into the member in an attempt to tighten the nut against a firm surface, showed. Unfortunately, this was another personal injury case. This timber broke at the ground line, hitting a little boy in the head, killing him. This case is just a series of mistakes by well-meaing, but uninformed, people, for which treatment, again, would not have been the solution. But the school's solution--replacing the wooden equipment with steel--also is ill-advised. If my kids were to fall from a piece of playground equipment, I'd much rather they hit their head on wood than a steel 6x6. Wooden roofs should always have a pitch to them, for natural, passive, drainage. All that's needed here is a single pinhole through the roofing material and this roof is a goner. I guess you could get away with this by using adequately treated wood for everything below the water, but why bother? Change the design! Finally, on the West Coast of the U.S., we are building with green lumber which, in many cases, already is infected with decay fungi--the same ones responsible for most above-ground decay. Since most ordinary decay fungi go dormant between wettings, we are building our buildings with the fungi which will decay them already provided. All that's needed is water. The solution to this problem is not treatment, it's kiln-drying. Although I've shown you a number of examples of inadequate wood performance in structures for which I've suggested that preservative treatment would not be the appropriate solution, there are a number of things we should do, I believe, to position preservative treatment in a way to make it available as a solution if other methods prove unsuccessful. Some challenges to preservative research which I recognize would include the following. We need to improve penetration, especially in refractory species like Douglas-fir. Adequate drying prior to treatment, even in large members would help. New approaches, such as vapor metal and cold plasma treatments may hold promise for their ability to increase penetration. We need to find a substitute for visible incisions and, at the same time, achieve deeper incising. I have frequently heard from architects, "I won't use treated wood because those little knife marks are ugly." We need to improve quality control; is the ability to guarantee treatment that meets certain specifications in 100% of pieces treated really not attainable? In our emerging global economy, perhaps quality assurance needs to be taken on by one, or more, international organizations, as in the ISO9002 systems for other commodities. Finally, is it completely impossible to give those parents a "non-toxic" treatment for their playground equipment? The solutions to these issues will require cooperation. Going it alone is an outmoded concept, which, in this era of secrecy and non-cooperation in academia, probably means that the treating industry is going to have to get together and do these things, if they are going to get done. I do, however, have the answer for one of the oldest philosophical questions about being alone. Alan asked me to be a little outrageous and present things that would cause attendees to talk about them in the halls the rest of the week. I think I've done that, Alan. If I went a little overboard, I apologize.
W W Wilcox
Work program of CEN/TC 38 (April 1993). Durability of wood and wood-based products
1993 - IRG/WP 93-20012
A review of environmental emissions from building and construction materials in comparison with preserved wood
2005 - IRG/WP 05-50224-11
A review of the public domain literature concerning emissions to the environment from materials which are used in the construction of buildings (e.g. Concrete, Asphalt, Galvanised Steel), in comparison with preserved wood, and a review of the approaches taken by the construction sector in assessing the risk from environmental emissions, in comparison with the approaches taken by the wood preservation sector.
E F Baines
Treatment of dried sawn spruce and redwood building timbers with water-borne preservatives under a scheme for the quality control of the preservation and preserved wood in the Netherlands
1978 - IRG/WP 3123
Treatment of dried sawn spruce and redwood Building Timbers with water-borne preservatives under a scheme for the quality control of the preservation and preserved wood in the Netherlands. The aim of this article is to give the reader a modest description of the evaluation of fundamental research in wood preservation into a practical application.
H F M Nijman, N Burgers
Results on termite resistance of building materials against Coptotermes formosanus by choice test
1998 - IRG/WP 98-10275
Various building materials, included wood species, wooden board materials, thermal insulation materials and fire-protection materials, were tested for grading of termite resistance against Coptotermes formosanus. The dimension of most specimens were 2x2x2cm3. Ten repeats were prepared. The specimens were put between Akamatsu sapwood control specimens on a laboratory cultured mound colony of termite, Coptotermes formosanus. After 1 month of attack to termite, the specimens were removed from the mound colony and cleaned up. Then these final mass were weighed. The grading of termite resistance was initially estimated by mass loss of specimens. This grading was corrected by visual observation. Japanese 3 domestic species, cypress pine, Alaska- ceder, kapur and mahogany were indicated rather high termite resistance. In the case of Siberian red pine and Gmelina, the valued of termite resistance were shown variable. Tropical species plywood, inorganic board and radiata pine MDF, were shown rather high termite resistance. Other board materials were shown rather less termite resistance. Most of commercial soft wood plywood and OSB were very sensible against termite. Most common thermal insulation materials in Japan were estimated very sensitive against termite. In the case of fire protection materials, expanded concrete was rather good against termite but plaster board was very sensible against termite.
K Suzuki, K Hagio
Experimental real building evaluation of termite attack - Effect of the space between the mat foundation and the thermal insulation
2000 - IRG/WP 00-10374
For evaluating the termite resistance of the real house foundation, specially in the case of thermal insulation systems for foundation walls, thermal insulation which can be attacked by termite, must be evaluate. Because of the difficulty of the water penetration of thermal insulation, the water barrier systems can be protected against termite attacks, in our opinions. The observation on the process of the penetration by termites and ones of a traditional barrier system against termites were evaluate by the real building scale test method.
K Suzuki, K Hagio, Y Tanaka
Reticulitermes (Ins., Isopt.) in Central and Western Europe
1969 - IRG/WP I 5A
Reticulitermes flavipes (Kollar) has established itself in Hamburg and Hallein coming from the east of North America. In France, on the northern boundary of termit occurrence, Reticulitermes santonensis are distinguished from Reticulitermes lucifugus by special activity and resistance. According to comparative investigations with colonies of several Reticulitermes species of different origins regarding the influence of temperature and soil moisture on the feeding activity and the viability of termite groups, Reticulitermes flavipes from Hamburg and one originating from Wisconsin (USA) show racial differences from the Hallein species originating from South Carolina. The first shows a daily rhythm of activity and are strong gallery builders, while the two latter lack these properties. Certain morphological differences may be correlative to the two bio-ecological races of Reticulitermes flavipes. Reticulitermes santonensis shows biologically and ecologically far greater similarity with Reticulitermes flavipes from Hamburg and Wisconsin than with Reticulitermes lucifugus. The samples from La Rochelle have symbiotic flagellate species which were otherwise only found either with Reticulitermes lucifugus or with the American Reticulitermes species. Morphologically the species occupies an intermediate position. Reticulitermes santonensis is likely to be a hybrid of Reticulitermes flavipes and Reticulitermes lucifugus, with the properties of a vigorous hybrid. So far it has been impossible to explain why up to now only Reticulitermes flavipes was able to establish itself sporadically in Central and West Europe.
Japanese Classification of Wooden Building Members for ISO Use Classes according to the Building Code in Japan.
2006 - IRG/WP 06-20337
Because of the international approve of use class system for the biological degradation of wood by ISO/DIS 21887 and ISO/DIS 21892, Japanese committee of ISO/TC165/SC1 asked to the JWPA for classify the wooden commodities by use class of these draft ISO. The JWPA was prepared a draft use class model in Japan. Japanese building code systems are described and Japanese draft use class system is also described.
Building With Wood an strategic action in Spain
2010 - IRG/WP 10-40530
This paper explains the objectives and results of the “Building with Wood” project, mainly at Spanish level. As far as the wood preservation field is concerned, the present abstract also informs about the main goals of the project in this matter.
M Conde García, J I Fernández-Golfín Seco, J Galván Rodríguez
Reticulitermes (Ins., Isopt.) in Mittel- und West-Europa
1969 - IRG/WP I 4
In Hamburg und Hallein hat sich Reticulitermes flavipes (Kollar) aus dem Osten von Nordamerika eingebürgert. An der Nordgrenze des Termitenvorkommens im Westen Frankreichs zeichnet sich Reticulitermes santonensis Fetaud gegenüber Reticulitermes lucifugus durch besondere Aktivität und Widerstandsfähigkeit aus. Nach vergleichenden Untersuchungen an Kolonien verschiedener Reticulitermes-Arten mehrerer Herkünfte über den Einfluß von Temperatur und Bodenfeuchtigkeit auf Fraßtätigkeit und Lebensfähigkeit von Termitengruppen weisen die Reticulitermes flavipes-Tiere von Hamburg und einer Herkunft aus Wisconsin (USA) gegenüber den Tieren von Hallein und einer Herkunft aus South-Carolina Rassenunterschiede auf. Die ersteren zeigen einen Tagesrhythmus der Aktivität und eine starke Galleriebautätigkeit, die den beiden letzten fehlen. Gewisse morphologische Unterschiede lassen sich den beiden ökologisch-biologischen Rassen von Reticulitermes flavipes zuordnen. Reticulitermes santonensis ähnelt biologisch und ökologisch Reticulitermes flavipes von Hamburg und Wisconsin weit mehr als Reticulitermes lucifugus. Die Tiere von La Rochelle besitzen symbiotische Flagellaten-Arten, die sonst nur entweder bei Reticulitermes lucifugus oder bei amerikanischen -Arten vorkommen. Morphologisch nimmt die Art eine Zwischenstellung ein. Reticulitermes santonensis dürfte eine Kreuzung aus Reticulitermes flavipes und Reticulitermes lucifugus mit Eigenschaften eines luxurierenden Bastards sein. Bisher läßt sich nicht erklären, warum sich bislang nur Reticulitermes flavipes vereinzelt in Mittel- und Westeuropa einbürgern konnte.
Study on the treatment of construction timbers by diffusion methods
1983 - IRG/WP 3252
Several species of timber that could be used for constructional purposes have to be pressure impregnated before such use. Pressure impregnation requires expensive equipment, and needs specialized trained operators, etc, which is not possible in most parts of India. Some timbers cannot be pressure impregnated, but can be treated by diffusion. Diffusion treatments could protect these timbers with simple inexpensive apparatus, using local resources and labour. It is our purpose, therefore, to locate such species which are commonly used in India for constructional purposes, and to preserve these by diffusion; to check if the results are satisfactory, and to find a preservative and simple procedure for the treatments of these timbers based on their treatability.
V R Sonti, B Chatterjee
Development on Damage Functions of Wood Decay for Building Envelope Design
2005 - IRG/WP 05-10556
For the hygrothermal analyses of building envelope systems for insulation design, we tried a natural decay test of wetted wood specimens without any inoculation of fungi. Three principal experimental types: under steady-state conditions (Experiment A), at a cyclic water dripping under Non-steady conditions (Experiment B) and at a cyclic water dipping under-steady conditions (Experiment C), were carried out for this purpose. After these tests, each specimen was determined its longitudinal compression strength. The detection of decay was checked this standard strength value by species according to Japanese building code and its corrected value by these moisture contents. As the results of the Experiment A, some fungal growth was observed within 10 weeks at the moisture contents of levels between 30wt% and 70wt%. As the results of the Experiment B, the simulated condition of short time condensation in summer was observed fungal growth but not affected decay problems within 124 weeks. As the results of the Experiment C, the simulated condition of periodical wetting as under floor or bottom of cladding was not observed any decay.
H Suzuki, Y Kitadani, K Suzuki, A Iwamae, H Nagai
The dip diffusion treatment of tropical building timbers in Papua New Guinea
1972 - IRG/WP 310
In Papua New Guinea a dip diffusion process using a multi salt preservative developed by C.S.I.R.0. has been in commercial use for 8 years. Over 200 million super feet (236,000 m³ ) of timber has been treated during this period and current rate of treatment is 34 million super feet (80,400 m³ ) of timber per year in 70 licenced treatment plants. The process has been found to be simple to apply, convenient to control and has proved very successful in the protection of timber used out of ground contact and protected from the rain. No serious health hazards to process operators or product users have come to light. In common with other countries in the wet tropics P.N.G. is faced with very serious biological deterioration hazards to timber in houses but dip diffusion has overcome the major problems. During the 16 years in which dip diffused timber has been in service in P.N.G. there have been no notable falldowns, the only falldowns reported being in mouldings in which heavy dressing has removed the preservative envelope, but this is a very rare occurrence and cannot be considered of economic importance.
C R Levy, S J Colwell, K A Garbutt
Review of Mold Issues in North America and Mold Research at Forintek
2003 - IRG/WP 03-10458
Over the last decade, air quality in homes and workplaces has become a high profile issue especially in relation to mold, receiving considerable media, public and legal attention. Forintek Canada Corp. and the wood industry in general have experienced large increases in inquiries regarding mold and the suitability of wood as substrate for its growth. Because wet wood supports growth of fungi the public perceive wood used in building envelope as a major source of mold and this can affect wood’s image in markets and could be exploited by competitor industries. Forintek reviewed the existing and relevant information about mold, substrates that support its growth and the health issues associated with mold and water damaged buildings. Several projects and collaborative efforts with other groups have been initiated to deal with recognized knowledge gaps. This paper covers the history of mold hysteria, recent statements by authorities on mold and health and summarizes some of Forintek’s recent work. This includes: survey of mold and staining fungi on KD lumber; database of literature on mold, building materials and health; limiting conditions for mold growth, hidden mold and its movement into living spaces and a lab test method for mold resistance of wood products.
A Uzunovic, A Byrne, Dian-Qing Yang, P I Morris
Risk reduction from curative treatments, restoration and maintenance of building and individual housing - simple precautions that make the difference
2005 - IRG/WP 05-50224-15
This document explores the potentialities of risk reduction, from activities of remediation in construction, developped at small scale by professionals or individuals on targets like moulds, rots, termites and other wood destroying insects, with products distributed for professional or do-it-yourself purposes. At the first stage, an inventory of the type / interest of products / processes is carried out, with the identification of the sequences, including the fate of wastes and the resulting exposure for the compartments of interest. For health aspects, a crude practical evaluation of the exposure of direct receptors, operators, and indirect ones, inhabitants and the public in the vicinity, to the pathologies and their remediation, seems possible. This exercise aims to provide the users of products with the minimum set of tools and criteria of direct exposure assessment, prior to their use, based on available documentation, regulation and warnings. The best case occurs with the access to material safety data sheets and the corresponding labelling. Per default, they take available products from the shelf (approved for marketing or restricted use, doses, conditions of application), with the support of suppliers and local requirements. Regular training is one way of progress, the obligation of result with procedures adapted to the site of the building and its own exposure, another route of improvement. As works in this field are often non typical, there is still room for the optimisation of individual options, based on experience, to locate the necessary dose and performance at the right place. Description and examples are provided.
How predictive are laboratory experiments for assessing the effects of chitin synthesis inhibitors (CSI) on field colonies of terrnites? - A comparison of laboratory and field data from Australian mound-building species of termit
1996 - IRG/WP 96-10143
A singular advantage of using mound building species of termite is their directly accessible nest. This allows evaluation of control methods by accurate assessment of the effects at the colony level. The mound building species Coptotermes acinaciformis (Froggatt) and Nasutitermes exitiosus (Hill) were used to test the CSI, hexaflumuron, in laboratory and field trials. Laboratory results showed that hexaflumuron was not repellent and it eliminated four gram groups of C. acinaciformis at a dose of 125 ppm and above within eight weeks. Groups of N. exitiosus were not affected by hexaflumuron: survival and wood consumption at doses of 0.25 to 1000 ppm were no different to those at zero ppm. Similar responses were obtained with the CSI triflumuron. These results would predict elimination of colonies for C. acinaciformis but not for N. exitiosus. However, field colonies of C. acinaciformis and also of N. exitiosus could be eradicated when exposed to hexaflumuron. Larvae and earlier stages of workers and nymphs died first, most likely during moulting, whereas the older foragers, which are the stages most often used in laboratory experiments, lived the longest. The latter was most pronounced in N. exitiosus. These results are the first to show the effects of a CSI on an entire colony, and demonstrated unambiguously the elimination of colonies after foragers had fed on bait matrix treated with hexaflumuron. Laboratory evaluations, using groups of older workers and soldiers, can fail to accurately predict the impact of these products at the level of most concern, the colony.
M Lenz, P V Gleeson, L R Miller, H M Abbey
Composting of waste building up in sawmill dipping basins
1990 - IRG/WP 3570
We have studied composting of waste building up in dipping basins at sawmills although this waste can also be disposed of by incineration. Controlled composting within the sawmill area seems to be a feasible method. Another possibility is to accomplish composting directly at the local dumping site. Waste containing antistain chemicals is generally classed as hazardous. It cannot therefore be placed as such at common dumps. However after successful composting the permission to do so can probably be obtained. The composted dipping basin waste might also be suitable as land filling or in some cases as soil improvement material - at least in parks and green belt areas.
I A Linderborg, U Ek
Alkaline building materials and controlled moisture conditions as causes for dry rot Serpula lacrymans growing only in houses
1985 - IRG/WP 1272
Dry rot Serpula lacrymans ( Fr.) S.F. Gray is commonly found in houses, though never with certainly in nature, like other wood destroying fungi which grow both indoors and outdoors. In investigating series of dry rot instances it was shown that this fungus is always found in covered places, close to a moisture source, the distance being from 0 a maximum of 600 cm. Owing to the dry rot has been able to humidfy woodwork to the optimum condition of 20-30% wood humidity, while a lethal water content of 55% would be reached outdoors. At the same time the close presence of alkaline building materials, such as mortar, a clay layer, plaster or concrete has been observed in all instances, the average distance being from 0-100 cm. By neutralizing the dry rot fungus large production of oxalic acid the alkaline materials are able to adjust the pH to optimum levels. These two conditions are the reason why the dry rot fungus only occurs in houses.
Characteristics and quantity of impregnated wood waste in Germany
1995 - IRG/WP 95-50041
The disposal of wood waste in Germany is one of the main problems not only for the wood preservation industry but also for all concerned with wood waste. Data on characteristics and quantity of wood waste are still needed. Based on criterions given in a previous paper (IRG/WP 93-50006), several assortments have been characterized with regard to their hazardous potential and their logistical aspects. Results show that mixed assortments are those with the highest quantities. Each year about 2 Mio t of wood from demolition of buildings and from building sites have to be disposed. This accounts much more than the whole field of timber from landscape (ca. 220.000 t/a), crossties (ca. 6085.000 t/a) and poles (ca. 25.000 t/a). Timber from landscape, however, has a high hazardous potential and is hard to collect because of its broad distribution (e.g. private households). For assortments with small annual quantities (e.g. cooling towers, wooden silos) specific disposal structures are not realistic. At present most of the assortments cannot be reused or recycled either due to their hazardous potential or to their unfavourable disposal structures. For timber from landscape as well as for timber from demolition of buildings incineration in specific plants should be preferred.
A Voss, H Willeitner