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The influence of cement and calcium compounds on the performance of CCA preservatives
1983 - IRG/WP 3221
The influence of cement and calcium compounds on the durability of untreated and CCA treated wood is considered. Calcium compounds were found to reduce the toxicity of a CCA preservative to a soft rot fungus at copper to calcium ratios of 1:1 and 1:10 using a cellulose filter paper technique. Further studies are outlined and some possible mechanisms by which cement and calcium compounds may affect the performance of CCA preservatives are discussed.
R J Murphy


Wood in concrete. Summary of discussion at IRG 14, Surfers Paradise, Australia
1984 - IRG/WP 3264
The performance of untreated and preservative treated wood when placed in direct contact with concrete was considered in a discussion session at IRG 14. While published reports in this area are scarce, research is in progress internationally and a variety of practices are currently available to minimize any additional hazard posed by contact with concrete. This report summarizes the points raised at the IRG discussion.
R J Murphy


The use of zirconium as an inert fixative for borates in preservation
2001 - IRG/WP 01-30256
Stand-alone borates have been used in internal protected situations as wood preservatives for about 60 years. They have not been deemed acceptable for external situations because of their leaching characteristics. Work carried out to reduce the leachability of borates has been reviewed briefly here, and a specific fixation agent based on zirconium has been tested in standard leaching and decay tests. It was found that the performance of zirconium could be optimized for fixation at specific drying temperatures and at higher formulation pH. Using sufficient quantities of ammoniacal zirconium carbonate and potassium zirconium carbonate such formulations are then able to pass both Standard European and American Wood-Preservers' Association methods designed for testing exterior wood preservatives. Formulations based on borate with a zirconium additive are probably suitable for use in exterior above ground and possibly ground contact situations. As only initial indicative tests have been carried out so far, further testing with a range of wood destroying organisms and field tests should be carried out to evaluate this system further.
J D Lloyd, J L Fogel, A Vizel


Collaborative soft rot tests: Results of analyses of soil samples
1976 - IRG/WP 263
C R Levy


Leachability of borate-modified oriented strandboard: A comparison of zinc and calcium borate
2002 - IRG/WP 02-40232
The leachability of boron in zinc and calcium borate-modified oriented strandboard (OSB) was investigated in this study. The leaching experiments were conducted by exposing edge-sealed OSB samples under running water for 8, 24, 72, and 216 hours. The results were compared with those from the unleached controls. Boron leaching of the modified OSB occurred upon the initial water exposure, and the leaching rate decreased as the leaching time increased. Borate type, initial BAE level, wood species, and sample thickness swelling significantly influenced the leachability. There was no consistent effect of polyethylene glycol (PEG) on zinc borate leaching. Calcium borate with a smaller particle size helped reduce its leachability. The glueline washing due to thickness swelling of the test samples under water and decomposition of the borate to form less water-soluble boric acid are thought to be two possible causes for the observed leaching. The relationship between assayed BAE and leaching time followed a decaying exponential function for zinc borate OSB and a Harris decaying power function for calcium borate OSB. The material constants of the regression models allow comparing leachability of the modified OSB for various wood species. A unified leaching method for treated wood composite materials is needed.
S Lee, Q Wu


Inhibition of wood decay and termite damage by calcium precipitation
1996 - IRG/WP 96-30111
Fungal decay of wood in service, especially brown rot, results in billions of dollars (US) of losses annually. Recent environmental restrictions, both U.S. and international, are limiting or eliminating the use of broad spectrum biocides for wood preservation, primarily due to problems with disposal. In order to design new, environmentally benign methods for control of wood decay fungi, it is essential to understand the precise sequence of biochemical events as wood is colonized. The production of polygalacturonase (PG) and hydrolysis of bordered pit membranes during incipient brown-rot decay has recently been described by our laboratory. One key to pectin hydrolysis by plant pathogens has been shown to be fungal production of oxalic acid which lowers the pH of the substrate and chelates calcium ions. Production of oxalic acid may serve a similar role during incipient wood decay as calcium oxalate has been visualized by scanning electron microscopy during both brown-rot and white-rot decay. Therefore, it was hypothesized that in situ precipitation of existing calcium ions in wood may prevent the cascade of biochemical events involved in colonization of wood by brown-rot fungi, expecially hydrolysis of bordered pit membranes. Preliminary experiments in our laboratory have shown that brown-rot fungi, white-rot fungi, and termites are inhibited from effecting weight loss of wood following pretreatment of wood blocks with the selective water soluble calcium precipitating agent N,N-naphthaloylhydroxylamine (NHA).
F Green III, T A Kuster, L Ferge, T L Highley


Oxalate production and calcium oxalate accumulation by Gloeophyllum trabeum in buffered cultures
1994 - IRG/WP 94-10075
Most basidiomycetous fungi produce oxalic acid as a result of their metabolic activities and nutrient procurement. There is currently a renewed interest in the role that oxalic acid may play in the decomposition of wood by basidiomycete fungi. It has been observed that although most wood degrading fungi have the capacity to produce oxalic acid, not all of these organisms express this capacity equally in the wood environment. In addition, not all of the fungi which produce oxalic acid will accumulate this metabolite. Very often the production of oxalic acid is coincident with the precipitation of oxalate salts such as calcium oxalate. At this time it is unclear as to what controls the differential production and accumulation of oxalate by wood degrading fungi. An investigative series of experiments was established using the brown rot fungus Gloeophyllum trabeum to examine the conditions which favor oxalate production and accumulation as manifested through the production of metastable calcium oxalate dihydrate crystals. Batch cultures which were buffered by base cation exchange sites of mineral amendments stimulated the production of calcium oxalate crystals. The results of these buffering experiments indicate that at pH values below approximately 6.0 there is a diminution of oxalate accumulation, and that a pH environment of approximately 3.0 is consistently attained in weakly buffered cultures inoculated with this fungus. These pH values correspond to the pH optima for oxaloacetase (EC 3.7.1.1) and oxalate decarboxylase (EC 4.1.1.2) respectively, and thereby suggest a mechanism for both pH control and oxalate production and accumulation.
J H Connolly, J Jellison


Inhibition of termite damage by N'N-napthaloylhydroxyamine (NHA): Reticulotermes flavipes (Kollar) vs. Coptotermes formosanus Shiraki
2000 - IRG/WP 00-10354
The calcium precipitating agent NHA has been shown to protect southern yellow pine (SYP) from wood decay and termite damage comparable to CCA in field tests (Gulfport, MS) for two years (Crawford and Green, 1999). In a collaborative study, SYP wood blocks were vacuum treated with three concentrations of aqueous NHA and exposed in a no-choice test to Eastern subterranean termites (FPL, USA) and Formosan subterranean termites (WRI, Japan) to determine protection against termite damage. Individual blocks (leached and unleached) were exposed to R. flavipes (AWPA) or C. formosanus (JWPA) for 3-4 weeks. Mean weight loss of wood blocks after termite exposure ranged from 0.0 to 18.0% for R. flavipes and 6.0 to 20% for C. formosanus. Wood blocks exposed to R. flavipes were completely protected by 0.5 and 1.0% NHA, but weight loss in similar blocks challenged by C. formosanus were 6.0% and 6.2% respectively at the same concentrations. NHA acted as an effective termiticide for R. flavipes with 100% mortality after 3 weeks, but only soldiers were preferentially killed in C. formosanus. Formosan subterranean termite workers showed enhanced resistance to NHA treatment when compared to Eastern subterranean termites.
F Green III, S T Lebow, T Yoshimura


A comparison of inductively coupled plasma spectroscopy and neutron activity analysis for the determination of concentrations in wood
1993 - IRG/WP 93-10048
As wood decays the ionic composition changes, with increases often being seen in the concentrations of Ca, Mg, Fe, Mn and sometimes K. The concentration of eight cations in red spruce sapwood and heartwood samples was determined independently by inductively coupled plasma spectroscopy (ICP) and by neutron activation analysis (NAA) as part of an effort to standardize our analytical procedures and create a uniform wood standard for use by multiple researchers. Preliminary studies indicate a difference in the values of Ca and K as estimated by ICP and NAA, possibly due to a loss of these elements due to volatilization during ashing.
J Jellison, J Connolly, K C Smith, W T Shortle


Decay and mold resistance of borate modified oriented strandboard
2003 - IRG/WP 03-40260
Decay and mold resistance of zinc borate (ZB) and calcium borate (CB) modified oriented strandboard (OSB) from southern mixed hardwoods and yellow pine was investigated in this study. Tests were done with brown rot, Gloeophyllum trabeum, and white-rot, Trametes versicolar, fungi for 8 and 12 weeks, respectively. Wood species and fungus type had significant influence on the decay resistance. Decay caused by brown rot was evident for all untreated southern pine and mixed hardwood OSB controls. White rot, however, did not cause significant sample weight loss for both species groups. The incorporation of ZB and CB into the OSB provides suitable protection against brown- and white-rot fungi. No significant weight loss was observed from the treated OSB. Microscopic analysis shows that the hyphae were abundant in wood rays and cell walls in the southern pine OSB controls attacked by G. trabeum. Untreated samples from mixed hardwoods and commercial OSB were most susceptible to mold growth. The borate-modified OSB from mixed hardwoods and southern pine effectively prevented the mold growth. Mold resistance was achieved with increase of borate retention level in the samples. Mixed hardwoods OSB showed a higher susceptibility to mold growth than southern pine OSB with or without borate treatment.
Q Wu, S Lee, J P Jones


A comparison of the leaching resistance of diammine-copper complexes and copper carbonate precipitated in wood
1997 - IRG/WP 97-30158
Previous studies have shown that during treatment of wood with ammoniacal copper solutions, both simple copper precipitates and diammine-copper complexes are formed. The objective of the present study is to determine the relative importance of both forms of copper, on such aspects as preservative leachability and biological performance. In the current experiment, the leachability of copper carbonate precipitated in wood is compared with that of diammine-copper complexes. The results confirmed that both forms of copper resisted leaching by distilled water. However, when exposed to the more aggressive leaching conditions using the sodium citrate buffered solution, the diammine-copper complexes were significantly more ressistant to removal from the wood. Further studies are planned to examine the diammine-copper complexes present in the wood as well as the efficacy of these complexes against wood decay fungi.
Xiao Jiang, J N R Ruddick


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.
J Bech-Andersen


Old and new facts on the dry rot fungus Serpula lacrymans
1991 - IRG/WP 1470
The article collates some of the recent literature on the biology of the dry rot fungus Serpula lacrymans. The fungus can grow at 28°C, and maximum wood moisture is above 55%. Serpula Iacrymans degrades crystalline cellulose. The intensive production of extracellular oxalic acid is neutralized by calcium and iron. There is considerable variation among the strains with regard to factors such as growth rate, wood decay and response to preservatives. Possible alternative methods of eradication involve interference with the metabolism of nitrogen and sugars. Gel electrophoresis of mycelial proteins and immunological procedures provide valuable supplementary means of identification. Fruit-bodies can be obtained regularly in artificial culture. Inter-stock breeding of monokaryons to dikaryons up to the third generation shows differences among cultures with regard to growth, reaction to temperature, rate of wood decay and resistance to chemicals
O Schmidt, U Moreth-Kebernik


Investigations into the biology of Meruliporia incrassata
2004 - IRG/WP 04-10508
The dry rot fungus Meruliporia incrassata (Berk. and Curt.) Murr. is a highly destructive brown rot wood decay fungus and is a significant pest of wooden structures. The fungus, know commonly as ‘Poria’, is characterized in culture by strand mycelium and skin-like surface mycelium. In structural environments it is found to produce prominent water conducting rhizomorphs, is a copious spore producer, and is an aggressive brown rot fungus in wood. This research focuses on the growth of M. incrassata in modified ASTM soil block jars and on the organism's ability to sequester calcium, iron, and other cations from the environment. Four field isolates of M. incrassata, as well as M. incrassata ATCC 11236, and the related dry rot fungus Serpula lacrymans ATCC 36335 were grown on spruce wood in modified ASTM soil block jars for 12 weeks (ASTM 1994). Blocks were dried, weighed, ground and analyzed by ICP (inductively coupled plasma spectroscopy). Weight loss and levels of Ca, K, and Fe were greater in spruce wood decayed by the four field isolates than in wood incubated with the other fungi or with no fungi. The variability in ability to decay wood has implications for standardized decay testing. Understanding the sequestration and role of cations by this highly aggressive dry rot may aid in the development of appropriate control measures.
J Jellison, C Howell, B Goodell, S L Quarles


Production, function and neutralization of oxalic acid produced by the dry rot fungus and other brown rot fungi
1987 - IRG/WP 1330
The formation of oxalic acid by the wood-destroying fungi causing brown rot, is found to be the key which by hydrolysing the hemicellulose brings the cellulose in the tracheid wall in contact with the cellulase enzymes and yeld watersoluble sugars leaving only a lignin skeleton. To control the pH in the substrate the excess oxalic acid is precipitated to water insoluble calcium oxalate by the dry rot fungus in contact with a calcium source. As source glass can be used, however, mortar, concrete or clay soil is better. Heavy metals that form complex compounds with oxalic acid can substitute calcium certain to a degree. The wet rot fungus Coniophora putenea is not dependent on calcium like the dry rot fungus. By producing acetic as well as oxalic acid it might form a buffer solution which controls the pH in the substrate.
J Bech-Andersen


Serpula lacrymans the dry rot fungus. Revue on previous papers
1989 - IRG/WP 1393
It is found that the Dry rot fungus Serpula lacrymans grows in houses only because of its need for basic materials to neutralize the oxalic acid production or heavy metals which celate the oxalic acid. The average distance from the mycelium to the basic materials is found in average to be 14.2 cm with a variation from 0-100 cm. In contrast to Serpula lacrymans the Coniophora puteana and the Rigidophorus vitreus do not need calcium. The oxalic acid is found to hydrolyze the hemicelluloses and open for further break down of the celluloses. The excess oxalic acid is neutralized by calcium to the water insoluble calciurnoxalate which at last will be broken down by bacteria in the soil. The Dry rot fungus (Serpula lacrymans) (Schum ex Fr.) S.F. Gray, is found in houses and mines only in contrast to other wood destroying fungi which both grow indoors and outdoors in the nature.
J Bech-Andersen


Effects of bleaching process on the roughness values of wood surfaces of Lebanon cedar (Cedrus libani A. Rich.) and Black poplar (Populus nigra L.) using NaOH (sodium hydroxide), H2O2 (hydrogen peroxide) and Ca(OH)2 (calcium hydroxide)
2008 - IRG/WP 08-40403
Technical progress in the wood industry has been rapid in recent times. In this case, the quality assurance of the consumer products aligned with aesthetics value appears as one of the most important parameters. Because of the outer appearance of goods exert an effect on customers, interest in production of high quality surfaces of wooden commodities has increased essentially based on the surface smoothness (and/or the surface roughness of wood) aiming to reach the customer-oriented quality criteria. An aesthetics behaviour is being more influenced than the functional situation of the merchandise when the customers making the decision to buy wood products. It has been well estabilished that some of the properties of wood material (i.e. density, porosity, moisture content, fiber directions), and the wood machining process and its conditions (i.e. kinematics of the cutting process, wood sanding process) make the surface smoothness of wood problematic. There is a lack of information about the effects of bleaching process (i.e. one of the special technical ways to increase the aesthetics of wood products) on the smoothness of wood surfaces despite numerous reports published on the machining tools and the cellular structure of wood. In this study, therefore, effects of bleaching process on the surface roughness of wood was investigated for Lebanon cedar (Cedrus libani A. Rich.) and Black poplar (Populus nigra L.) using the bleaching chemicals NaOH (sodium hydroxide), H2O2 (hydrogen peroxide) and Ca(OH)2 (calcium hydroxide) by the two prescriptions with or without calcium hydroxide.
I Usta, E Aydinlar


Serpula lacrymans – calcium, iron, and foundering wooden boats
2009 - IRG/WP 09-10691
Serpula lacrymans is one of the most destructive wood-degrading brown rot fungi in temperate environments. Its virulence has often been linked to its ability to grow over non-woody materials and extract calcium (Ca) or iron (Fe) to promote wood degradation in buildings. This fungus has also been a severe problem in historic wooden warships and in modern wooden vessels, sometimes leading to foundering (break up) in high seas. In recent work, we have found evidence supportive of the theory that S. lacrymans can translocate and utilize elements from non-woody sources. In the research presented here, we provide data that complement earlier work suggesting that calcium can actually inhibit wood degradation by this fungus, while iron impurities can relieve this apparent stress. Oxalate analysis from agar, as well as SEM-EDS imaging of calcium oxalate crystals and direct hyphal contact with gypsum substrates, suggest calcium may bind oxalate non-productively and may limit its role in iron sequestration. Work by other researchers showing calcium can inhibit oxalate from detoxifying copper and showing supplemental iron may help fungi overcome copper-based preservatives support our observations. These results relate directly to cultural management of this destructive fungal pest and lend mechanistic information on the role of oxalate during brown rot.
J S Schilling, S M Duncan


Studies on Effect of pH on Copper Availability in Copper-Based Preservatives
2010 - IRG/WP 10-30549
Laboratory methods have been employed to investigate the pH effect on the copper solubility of basic copper carbonate. The pH was controlled using two different approaches. One was with the adjustment of pH of the solutions by acid or base using sulfuric acid or sodium hydroxide until the solution equilibriums were obtained for each defined pH. A second approach was to control pH with buffer solutions to provide the designated pH range. Differences in copper solubility at the same pH with these two approaches were observed. The results generated from this study are compared with previously presented data and are discussed in terms of the influence of methodology, potential interactions of component(s) and the effect of the pH control agents.
L Jin, P Walcheski, A F Preston


Copper Migration from Micronized Copper Preservatives Treated Wood in soil contact:
2011 - IRG/WP 11-50280
Emerging formulations of preservatives made with micronized basic copper carbonates with azoles and/or quat to control copper tolerant fungi have been used to replace formulations containing soluble copper to reduce the leaching of copper and the corrosion of metal in contact with wood. This study proposes to use laboratory soil leaching test AWPA standard (E20-08) to estimate the amount of copper soluble and mobile in micronized copper azole treated southern pine at 6.7Cu kg/m3 and micronized copper treated quat at cu retention of 3.3 kg/m3. treated wood were exposed to different soils with pH ranging from 4.7 to 8 for 12 weeks to evaluate the amount of copper leached from treated wood to soil. About 10% of initial copper was leached from MCQ treated wood to soil with pH 4.7 while only 2.0% cu were leached in soil with pH 8. For MCA, 9.6% and 0.6% were leached in soil pH 4.7 and 8, respectively, clearly indicating that copper from MCA and MCQ treated pine can be leached with higher amount at low acidic pH. Slightly more copper was leached from MCQ treated wood compare to MCA.
Lei Wang, D P Kamdem


Fire resistance of wood treated with potassium carbonate and silanes
2014 - IRG/WP 14-30657
This paper reports on the effect that organosilicon compounds and potassium carbonate and urea (PCU) have on wood flammability. The study focus on reducing wood flammability by promoting char formation through manipulation of the condensed phase decomposition chemistry. Potassium carbonate is known as an effective fire retardant, however it is easily leached out from wood and increases its hygroscopicity. The aim of the research was to assess the ability of selected organosilicon compounds to reduce potassium carbonate leachability from the treated wood. The study was performed through the mini fire tube (MFT) method, where fireproofing properties of the treated wood were evaluated. Pine sapwood treated with PCU at the retention of ca. 160kg/m3 showed 6% of wood mass loss as a result of combustion in MFT. The fireproofness effect has been reduced due to the ageing procedure and displayed 60% of wood mass loss. It has been shown that some selected silanes or their blends with siloxanes, superficialy applied on treated wood, allowed to retain PCU in wood and maintain its fireproofness. Wood mass loss resulting from sample’s combustion was significantly reduced (ML<10%). AEAPTMOS, VTMOS and a mixture of alkylalkoxysilanes turned out to be most effective agents limiting potassium carbonate leachability and maintaining wood fireproofness.
B Mazela, M Broda, W Perdoch


Bio-friendly preservative systems for enhanced wood durability - the first periodic report on DURAWOOD
2015 - IRG/WP 15-30677
The objective of the paper is the DURAWOOD scientific project carried out within Polish-Norwegian Research Programme, which lasts from September 2013 till August 2016. The aim of the project concentrates on the developing of a new, eco-friendly and biocide-free wood protective systems as an alternative to traditional, commonly used preservatives or coatings, containing biocides. Several wood preservatives containing traditional biocides are no longer desired on the market, due to the stricter toxicological requirements and an increasing ecological awareness of consumers. Therefore, formulating new wood protective systems, based on natural compounds, harmless to humans and the environment, is of the principle interest. On the other hand, it will also facilitate a longer period of carbon capture in wood, which will limit the greenhouse effect. Life cycle assessment (LCA), which is planned to perform for the selected model formulations, is a good example for an attempt to explain the interest. Besides, the implementation of novel solutions in wood protection will make it possible to use low quality wood material to manufacture high quality products (e.g. siding or cladding materials). In this manner such eco-friendly wood protection will be also a key factor reinforcing climate protection. The aim of this paper is to present some selected results gained so far. The model wood protecting systems were based on natural (alkaloids, propolis, plant oils) and synthetic (organosilicones, imidazoles) components as well as on neutral inorganic chemical - potassium carbonate. They were used individually or as a formulation for wood treatment. Wood samples made of Scots pine were treated by soaking or vacuum method and were subjected to mycological and fire tests. The so far results show that aminosilanes and mixtures thereof with natural oils are potential wood preservatives against microfungi and wood destroying fungi. Formulations containing aminosilanes, natural oils and potassium carbonate are potential wood fire retardants. It was also found that the most effective alkaloids were cytisine derivatives and caffeine. The highest antifungal activity among tested imidazoles was achieved by AK17 (1,10-di(3-hydroxymethylpyridinium)decanedibromide). The results of chemical analysis present evidence of interactions between compounds of the model formulations and wood chemical components.
B Mazela, M Broda, W Perdoch, L Ross Gobakken, I Ratajczak, G Cofta, W Grześkowiak, A Komasa, A Przybył


Study on the Effects of Flame Retardant in Dancheong for Korea Wooden Cultural Heritage
2015 - IRG/WP 15-40692
This study identifies the effect of the agent depending on environment change and conducted basic study to prepare criteria for stable application. Dancheong sample, which is similar to wooden cultural heritage, was manufactured to study the effect of the agent on dancheong. Regular observation on the samples located in inland and shoreline area in the country detected visible phenomena. Whitening, melting, peeling were observed, especially whitening was most frequently observed. This can be interpreted that whitening occurs when calcium carbonate reacts to phosphate system, a main ingredient of flame-proofing agent.
Hwa Soo Lee, So Jung Lee, Gyu Seong Han, Yong Jae Chung


A Green and Novel Technology for Recovering Copper and Wood from Treated Waste - Part I
2015 - IRG/WP 15-50309
Preservative treatment of wood extends its service life. The US consumes about 70 million pounds of copper and produces about 7 billion board feet of treated wood annually. Burning and reusing CCA and copper treated wood wastes are disallowed by US EPA due to health and environmental concerns. Millions of pounds of copper and wood are disposed by landfill annually. The objective of this study was to develop a green technology that can remove copper from the treated wood wastes so that copper and wood can be reused. In this study, seven different aqueous solutions were evaluated for copper removal from treated wood sawdust and chips. Citric acid demonstrated the highest efficiency by recovering 100% copper followed by ammonium citrate and ammonium carbonate/bicarbonate solutions. Formation of copper complexes with the ligands such as citrate and ammonium ions attributed to the key chemical mechanisms for efficient copper removal. The changes of extraction solution color progressively from yellowish orange to dark blue corresponded to the changes in the ratio of citrate ions to ammonia in the solutions. Citric acid has been used extensively as a food and cosmetic additive. The safety, high efficiency and low cost of citric acid compared to the chemicals previously reported for treated wood remediation can overcome the obstacles for commercial consideration. The performance demonstrated in the extraction study by the ammonium salts provides a novel extraction system with further cost reduction options. The finding of excellent copper removal using treated wood chips is very significant since it saves a great amount of energy required to produce sawdust. After removal of copper, the chips offer more opportunities than sawdust for reuse in landscaping, pulping, energy production and many other applications. With the development of such a green and novel technology, we can reuse millions of tons of wood and copper to protect the environment, save natural resources and benefit generations to come.
S Chen


Selection of heat flux value for wood fire retardants testing using MLC
2018 - IRG/WP 18-40846
One of more crucial elements of investigating treated wood combustion properties with the use of a cone calorimeter is a proper selection of heat flux (HF). The HF level is directly reflected in time to ignition and a thermal degradation degree. The ignition of raw wood or of wood ineffectively protected against fire occurs at a low HF level, i.e. 10-20 kW/m2. By contrast, the ignition of wood which is effectively protected against fire, may occur no sooner than at HF 50 or even at 75 kW/m2. The aim of the paper was to analyse the problem of the selection of heat flux intensity in both experimental and standard fire testing with the use of a mass loss calorimeter (MLC). The subject of the analysis was wood treated with protective agents of various durability and fire resistance. On the one hand, the high HF value for wood samples of low fire resistance restricts or even excludes practical applications of an MLC as a tool for the evaluation of fire protection efficiency. On the other hand, too low value of HF prevents wood either from ignition or from determination of its thermal degradation degree. It especially applies to the situation when wood is effectively protected against fire. In both cases, the problem arises at the interpretation stage of obtained results. The identified problem was presented on the example of wood treated with chemical compounds which are ingredients of commonly used fire retardants, i.e. MAP – monoammonium phosphate, DAP – diammonium phosphate and PC – potassium carbonate, well known for their fire retardant properties. They are also known for their high solubility, which proves their high leaching from wood resulting consequently in a significant decrease in fire retardant properties. Unfortunately a versatile research procedure was not proposed in the performed study. However, the necessity for the individual selection of physical properties of a combustion process was emphasised. The above forces an unconventional method of result interpretation.
B Mazela, W Perdoch, W Grześkowiak, A Batista


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