Your search resulted in 65 documents. Displaying 25 entries per page.
Improvement of some technological and biological properties of poplar wood by impregnation with aqueous macromolecular compounds
1992 - IRG/WP 92-3721
Poplars (Populus spp) belong to the most important tree species in afforestation programs of the Netherlands. Due to their rapid growth, the wood quality is usually low. Therefore, studies were performed to elucidate whether some technological properties and the resistance against fungal attack could be improved by impregnation with water-soluble resins. The results showed that swelling and shrinkage of poplar wood may considerably be reduced by a treatment with certain resins. The anti-shrink efficiency (ASE) strongly depends upon the resin type. An air-curing alkydresin based on polybutadiene and an air-curing acrylate modified alkydresin emulsion caused the best effects. Additions of wood preservatives to the resins further improved the ASE. Some disadvatages of the tested resins may be seen in their leachability with consequent loss of the dimension-stabilizing effects. The resins by themselves don't reveal fungistatic properties but an impregnation of poplar wood with these materials led in all cases to a better durability against Coniophora puteana and Coriolus versicolor. Leaching procedures influenced the durability in various ways. With resin/fungicide combinations, a good resistance against Coriolus versicolor could be reached even after leaching. SEM and EDXA methods were used to localize the resins in the cell walls and lumina and to detect the growth of mycelium in the specimens.
R D Peek, H Militz, J J Kettenis
Health aspects concerning the use of bifluorides in wood
1981 - IRG/WP 3173
An attempt has been made to find a correlation between the quantities F¯ and HF present among other ions in an 'Improsol' solution consisting of NH4F.HF and KF.HF, the quantity absorbed by the wood from this after immersion and the toxicological effects of this treated wood when it is used in rooms destined for the residence of people or animals or for the storage of foodstuffs.
H F M Nijman
Borate thermal treatments
1992 - IRG/WP 92-3715
Green, partially seasoned (air-dried, steam conditioned), or kiln-dried southern pine timbers were treated thermally using 15% disodiumoctaborate tetrahydrate solution. After treatment, sections were stored under non-drying conditions to allow for diffusion. Results showed that effective treatment meeting the AWPA minimum retention (0.17 B203 pcf [2.72 kg/m³] in the outer inch) and penetration (2.5-in [64-mm] or 85% of the sapwood) could be obtained only with certain combinations of seasoning, treatment, and diffusion storage. The best results in terms of both retention and penetration were obtained with material steamed and stored prior to treatment using a 10-min hot bath time. Kiln-dried timbers could not be treated effectively. The results suggest that non-conforming treatment of green or partially seasoned timbers will require higher solution concentrations, higher hot bath temperatures, and/or longer diffusion periods to meet required standards. Results also indicated that treatment of smaller stock in dimension sizes (up to 2-in [50-mm]) should be feasible.
H M Barnes, R W Landers, L H Williams
Survey of conditioning treatment practices in India
1978 - IRG/WP 3127
India has 75.3 million hectares (ie about 24% of total land area) under forests out of which the area of productive forests, from which industrial wood is available, is about 60 million ha. The Task Force on Forest Resources Survey has tentatively estimated that the total growing stock in Indian Forests is 24,000 million cubic metres (m³). The total recorded production of wood in the country is roughly estimated as 25 million m³ annually of which approximately 10 million m³ is demanded by various industries and the remaining is used as fuel. India, with developing economy needs very large resources of timbers for diverse purposes. There is already shortage of timber in the country for various wood based industries and it is expected this will progressively increase with the rapid pace of industrialisation. However, suitable measures are being taken to bridge the gap between demand and supply. The entire 10 m³ of industrial wood requires some sort of protection against wood-destroying agencies. Timber awaiting conversion during storage needs prophylactic treatment while for use as poles, fence posts, sleepers, building material, in cooling towers, boats, ships, in mines, in sea-water, etc., timber should be adequately treated with suitable wood preservatives to obtain satisfactory service life. Both heart and sapwood of non-durable species and only sapwood of durable species need protection against wood-destroying agencies. Wood Preservation on scientific and modern lines was introduced in India by Sir Ralph Pearson of the Indian Forest Service in the year 1908. In India, the first wood preservation plant was established at Bally in Howrah in 1854. Of the total timber extracted in India, only a very small proportion, estimated at about 5% is treated. This amounts to 0.45-0.50 million m³ of wood per annum. The total annual capacity of 140 preservation units, existing in the country at present, is estimated at 0.43 million m³ on single shift basis. IS: 401-1967 (Indian Standard - Code of Practice for Preservation of Timber) covers types of preservatives, their brief descriptions, methods of treatment, and the type and choice of treatment for different species of timber for a number of uses. This standard includes only such preservatives and methods of treatment which have given satisfactory results under Indian condition of service. According to this standard, whatever process of treatment is adopted, timber for treatment should be sound and should be dried to an appropriate moisture content (generally not more than 15% for open tank and 25% for pressure processes). All the wood working etc should be done prior to treatment. In case of timbers, specially some conifers having non-durable heartwood which is refractory to treatment, when treating thick members like railway sleepers, beams, piles, etc, incision of all the surfaces, other than the ends, to a depth of 12-20 mm is necessary.
M C Tewari
Checking of sodium pentachlorophenate fixation in wood
1990 - IRG/WP 3620
In order to estimate the volatilization of sodium pentachlorophenate from treated wood, wood samples treated with pentachlorophenate were analysed after various durations of an EN 73 weathering The results giving no clear evidence of volatilization, treated wood samples were put in a test chamber with precise climatic conditions, the air used in the experiment being analysed. The pentachlorophenate content in air was quantified: 1.8 µg/m³
M Lamour, H Sageot
Preservative treatment of Pinus elliottii
1987 - IRG/WP 3435
The treatment of Pinus elliottii with copper-chrome-arsenic preservative by four alternative seasoning and treatment methods is investigated. Steam conditioning followed by either alternating pressure method (APM) or 'Q' treatment resulted in inadequate preservative penetration. Air drying or high temperature drying followed by the Bethell process resulted in a high standard of treatment.
P Vinden, L Carter
Fixation of CCA in Pinus sylvestris after kiln-drying
1990 - IRG/WP 3594
Tanalith C Paste is 98% fixed and Tanalith Oxide C is 99% fixed irrespective of whether treated Pinus sylvestris is kiln or air dried. A schedule suitable for kiln drying of CCA treated Pinus sylvestris is described.
P Warburton, J A Cornfield, D A Lewis, D G Anderson
Exposure monitoring of creosote vapors
1989 - IRG/WP 3511
Creosote oils contain hundreds of compounds. During impregnation and handling of treated wood the main component in the vapors released in air is naphthalene. Other main components are alkyl naphthalenes, indene, phenol and its methyl derivatives, benzothiophene, diphenyl, acenaphthalene and fluorene. In the measurement of creosote vapors, naphthalene can be used as an indicator agent. One of the major urinary metabolites of naphthalene is 1-naphthol. To explore the relation between naphthalene concentration in the air and 1-naphthol in the urine of exposed workers we monitored air concentrations and collected urine samples from six men over a working week. 1-Naphthol concentrations in urine samples were analyzed by GC as a pentafluorobenzylbromide derivative. The average concentration of 1-naphthol in the Monday morning samples was 0.1 mg/l, in the Monday afternoon 3.1 mg/l, in the Friday morning 0.4 mg/l and in the Friday afternoon 2.9 mg/l.
P Heikkilä, M Loutamo, V Riihimäki, M Romo
Measurement of VOC emissions from curative treated wood: A new emission test chamber
2001 - IRG/WP 01-50166-13
A poor indoor air quality (IAQ) is now recognized as a potential factor affecting occupants health. There are three basic strategies to improve IAQ: source control, improvement of the ventilation and use of air cleaners. Usually, the most efficient way to improve IAQ is to eliminate the different pollutant sources or to reduce their emissions. In order to precisely measure emissions from building products and estimate the potential heath impact of emitted pollutants, standardised analytical methods are needed. The aim of this paper is to present the new standards prepared by the European Committee for Standardization (CEN) and the International Organization for Standardization (ISO) for the measurement of indoor air pollutants and their application to the characterization of emissions from wood products. The prestandard ENV 13419, subdivided in three parts, has been prepared by the CEN technical committee 264 : ??ENV 13419-1 : Building products - Determination of the emission of volatile organic compounds - Part 1 : Emission test chamber method, ??ENV 13419-2 : Building products - Determination of the emission of volatile organic compounds - Part 2 : Emission test cell method, ??ENV 13419-3 : Building products - Determination of the emission of volatile organic compounds - Part 3 : Procedure for sampling, storage of samples and preparation of test specimens. The two first parts of the prestandard ENV 13419 specify a general laboratory test method for the determination of the area specific emission rate of volatile organic compounds (VOCs) from newly produced building products under defined climate conditions in a test chamber (Part 1) or cell (Part 2). The third part specifies for solid, liquid or combined products, the sampling procedure, transport and storage conditions and preparation of test specimens. In France, those European prestandards have been translated by the French Normalisation Association (AFNOR) in three experimental standards : XP ENV 13419-1, XP ENV 13419-2 and XP ENV 13419-3 [1-3]. In parallel to the ongoing work at CEN, the technical committee 146 of International Organization for Standardization (ISO) has prepared the draft international standard ISO/DIS 16000 related to indoor air. Part 6 of this standard specifies a method for the determination of the emission of single volatile organic compounds (VOCs) and total volatile organic compounds (TVOC) from building materials using test chambers and cells : ??ISO/DIS 16000-6 : Indoor air - Part 6 : Determination of volatile organic compounds in indoor and chamber air by active sampling on TENAX TA sorbent, thermal desorption and gas chromatography using MS/FID. It is intended that, after the final voting stage, the CEN prestandards (Parts 1-3) will be taken over by ISO and that Part 6 of the ISO standard will be taken over by CEN as the fourth part of the ENV 13419 prestandard. As an example, the volatile organic compounds emissions from preservative treated wood samples were characterised according to the CEN ENV 13419-1 prestandard describing the emission test chamber method and to the ISO/DIS 16000-6 prestandard for the analytical method. Two representative wood preservatives (hydrodispersable and petroleum solvent formulation) were tested for this purpose. The VOCs concentrations in the test chamber were monitored during 6 days following a simulated curative wood treatment.
F Maupetit, O Ramalho, C Yrieix
Observations on the uptake and penetration of various liquids in clear heartwood and sapwood of Pinus radiata D.Don
1983 - IRG/WP 3224
Volumetric uptake of water (aqueous copper-chrome-arsenic (CCA)) or methanol, applied by bulk hydrostatic pressure to air dried clear heartwood specimens of Pinus radiata D. Don, far exceeds that of a wide variety of polar and non-polar solvents. In air dried sapwood, the volumetric uptake of CCA tends to be less than that achieved for most solvents including methanol. No comprehensive explanation of the penetration mechanism in these two substrates can yet be offered. High temperature drying effects a significant increase of volumetric uptake of all liquids by heartwood, but not by sapwood, possibly because air dried material is nearly saturated after pressure treatment.
J E Barnacle
Volumes and weights of different CCA-C treated wood poles, anchor logs and crossarms of REB at air dry condition
1996 - IRG/WP 96-40073
Researches revealed the unit volumes and weights at air-dry condition (12% MC) of different poles, anchor logs and crossarms species of REB from this world. The softwood products are lighter than hardwood products. Inversely the unit volumes of softwood poles are higher than those of hardwood poles. Red pine (Pinus resinosa), radiata pine (Pinus radiata), blue pine (Pinus wallichiana), fir (Abies densa) and spruce (Picea spineelosa) are the lightest poles and anchor logs with higher unit volumes (Poles). Sundri (Heritiera minor) is the heaviest timber species out of all listed timber species and raintree (Samanea saman) is the lightest timber species among hardwood species.
A K Lahiry
Remedial treatment of wood attacked by insects
1981 - IRG/WP 3175
A review is presented of remedial treatments against wood-boring insects in wood in service. Preconditions and fundamental principles of insect control are compared with the control of fungal attack and reasons are given for the fact that remedial treatments against insects are more commonly applied than against fungi. With regard to insect control measures with a simultaneous preventive effectiveness, information is given on preservatives, control measures as well as on testing the effectiveness of preservatives with eradicant action. An evaluation of 40 tests according to EN 22 or DIN 52164 revealed that a mean depth of effectiveness of 15 mm is obtained at mortality rates of 80-84% of Hylotrupes larvae. At a mortality rate of below 75% the mean depth of effectiveness was about 10 mm and above 90% it was about 27 mm. Among the control measures without any preventive effectiveness fumigation and hot-air treatments are referred to. With regard to biological control measures, practical results are not yet available.
Dynamics of pressure changes in wood during impregnation
1990 - IRG/WP 3615
Conventional methods of impregnation have to be improved for achieving better penetration of refractory wood species. Basic requirements for an adjustment of treatment schedules are, amoung others, a profound knowledge of the course of pressure changes in the wood during treatment. A new method of pressure measurement was developed which supplies exact and reproducible data. The results show that air pressure spreads more rapidly in wood than water pressure. In pine, water pressure is built up in radial direction within hours an declines slowly after pressure release. In spruce, air and water pressure spread more rapidly in green wood than in dry wood. Water pressure of 5 bar applied in radial direction is not achieved within 8 hours time. 5 minutes successions of pressure and pressure release have no effects at 10 mm depth. These findings call into question the conventional OPM technique of rapid successions of pressure and vacuum, and possibly allow easier treating techniques.
R D Peek, S Goetsch
Risk of pulmonary damage as a result of an evaporation of ca. 50 ppb = 42 mg HF, evaporated from wood treated by difluorides
1987 - IRG/WP 3401
In this review of the literature the effects of fluorides and fluorine on man are described, especially the low level effects of inhaled HF on human beings. The term "fluoride" is used as a general term everywhere, where exact differentiation between ionic and moluecular forms or between gaseous and particulate forms is uncertain or unnecessary. The term covers all combined forms of the element, regardless of chemical form, unless there is a specific reason to stress the gaseous elemental form F2, in which case the term "fluorine" is used.
H F M Nijman
Curing conditions for a low formaldehyde etherificated melamine resin
1998 - IRG/WP 98-40108
Waterbased methanol etherificated melamine formaldehyde resins have the potential to increase the resistance of impregnated wood against wood destroying fungi. Previous studies indicated that the resin with the lowest formaldehyde content tested showed the best results regarding fungal resistance, dimensional stability and formaldehyde emissions after curing. In the present paper the influence of curing-time and curing-temperature of the resin with the lowest formaldehyde content is presented. It is demonstrated, that a sufficient curing of the resin requires temperatures in the range between 120-140°C for a period of several hours. The addition of pure urea leads to reduced formaldehyde emissions while the anti-fungal effect of the resins increases or remains the same.
D Lukowsky, R-D Peek, A O Rapp
Zur Analytik von Pentachlorphenol und Tetrachlorphenol in der Luft und im Urin. [On the analytics of pentachlorophenol and tetrachlorophenolin the air and in urine]
1979 - IRG/WP 3139
Because of its excellent fungicide and insecticide properties PCP has been used for more than three decades in the field of wood preservation. Recently, however, its application has been criticized repeatedly. The motives for criticism were diseases, the origin of which was supposed to be closely connected with the use of pentachlorphenolic wood preservatives. The quantitative evidence of this substance in the air and in biological material is, therefore, of decisive importance. This paper deals with the methods of determining analytically PCP and TCP in the air and in urine.
A Dahms, W Metzner
Risk assessment of energetic valorization of treated wood - wooden recycling
1996 - IRG/WP 96-50072
The most useful method for the valorization of wood wastes and wooden wastes is energetic valorization. In France the percentage of wood treated by antisaptain products is around 30%. Currently with the growing regulation, there is a need for cleaner methods and technology to allow sustainable valorization. The preservatives concerned are common organochlorine compounds (NaPCP) less used nowadays in France and another product used at large scale now composed of quaternary ammonium and boron compounds. Results concerning air emissions during the combustion process, chemical analysis of process residues, toxicological evaluation of combustion exhaust gas in rats and ecotoxicological evaluation of residues is presented to assess the risk of recycling processes.
G Deroubaix, P Marchal, G Labat
A field test with anti-sapstain chemicals on sawn pine timber stored and seasoned under different conditions
1984 - IRG/WP 3245
Newly sawn timber of European redwood (Pinus sylvestris L.) was dip treated in four different anti-sapstain chemicals. The protectife effect against sapstain, mould and decay was examined after 10 weeks' and 10 months' storage in open and closed stacks. The results showed that the performance of individual chemicals was different in open and close stacks, although the wood as well as the other storage and handling conditions were identical. This makes it possible explain some of the reported differences in performance of chemicals in different locations.
D J Dickinson, B Henningsson
A comparison of effectiveness of three waterborne preservatives against decay fungi in underground mines- An appraisal
2005 - IRG/WP 05-30366
To understand the effectiveness of waterborne preservatives and to explore the behaviour of roof supporting poles after pressure treatment, an experiment was conducted and thorough investigation was carried out during the last decade in the underground mines. Prior to commencement of the experiment, a survey was conducted at different depths in underground mines and collected decayed wood samples and got them identified. The waterborne preservatives used in underground mines were CCA, CCB and ACC. Two species of timbers namely Casuarina equisetifolia and Eucalyptus hybrid were treated by pressure process. Absorption of preservatives were calculated and penetrations were carried out on selected poles. Retention of salts were estimated. Preservative treated poles along with controls were installed at different depths consisted of varied environmental conditions of relative humidity, temperature and water seepage in underground mines. Absorption on the condition of test poles and effectiveness of preservatives were carried out after every six months for over 8 years. Observation revealed that untreated controls were destroyed by decay fungi within 3 to 5 years, whereas treated poles remained serviceable even after 8 years of exposure and estimated to last for over 12 years. Environmental factors like warm and humid air coupled with water seepage contributed for rapid decay of timbers in mines. The overall observation on the efficacy of preservatives indicated that in spite of a close competition among preservatives for superiority, CCA and CCB were found effective against decay fungi as compared to ACC.
A note on te seasoning, preservative treatment and suitability of debdaru (Polyalthia longifolia Benth & Hooker.) for poles
1995 - IRG/WP 95-40056
The main work is to determining the suitability of Debdaru (Polyalthia longifolia Benth.) as poles from Government and Village forests are investigated. The poles of Debdaru are easily treatable with CCA preservative by full-cell pressure method, but difficult to dry (air & kiln). Proper quality control must be maintain from procurement to treatment, specially during physical selection & drying (air & kiln) otherwise it may be discard as pole. Debdaru poles have been found suitable for power and Telecomunication lines with very keen care.
G N M Ilias, M D Rokib-ul-Hafiz
Kiln drying of poles as a means of solving the problems of pre-treatment decay in poles
1985 - IRG/WP 1263
The concept that pre-treatment decay can cause wide variation in the treatability of wood and especially wood poles has caused much discussion and debate in wood preservation circles. Yet it seem only logical that if decay has effected the strength characteristics of the wood and caused a differential moisture content in the wood the treatment of the end product will be highly variable and the longevity of the product will be unpredictable. Quite simply the one proven solution to the problem seems to be to artificially season the wood, usually by kiln drying, prior to treatment. This paper briefly reviews 1984 observations of the success of one treating operation in the Republic of South Africa in reducing the deterioration found during proof loading of all the poles produced. A literature survey is included to review the research accomplished to date to show that the results are truly valid. It is hoped that this paper will serve as a literature reference to other researchers in this subject and that they will contribute their findings to the work of the working group on pre-treatment decay in wood.
J A Taylor
The wood-attacking insects in wooden houses of an old open air museum in southern Finland
1989 - IRG/WP 1409
Harmful insects of wood in a open-air museum were investigated in 1985-1988 by order of the National Board of Antiquities and Historical Monuments of Finland in nine old log houses. Many thousands of insects and altogether 1073 anobiids (Coleoptera, Anobidae) were obtained by window and light traps. The most common Anobiidae-species were Hadrobregmus confusus (Kraatz) 60.3%, Hadrobregmus pertinax (L.) 30.6% and Ernobius mollis (L.) 8.9%. The amounts of trapped insects varied in different houses and the flight time of anobiids varied greatly according to yearly weather conditions.
H Viitanen, M Pulkkinen
The effect of pretreatments on the impregnation of air-dried sawn Belgian spruce
1988 - IRG/WP 3490
In general the impregnation of airdried spruce results in a variable treatment and limited penetration. This is the result of pit aspiration that occurs during drying of the spruce sapwood and heartwood. Spruce timber is becoming of greater importance in Belgium and hence research for better treatment of this vulnerable wood species is needed. Squared airdried timber of different dimensions were extracted from 10 winter-felled logs (Picea abies (L.) Karst) and impregnated with preservative used for constructional purposes. Partly the material was presteamed or waterlogged. Prior to the preservative treatment both groups were reconditioned to the same moisture content as the reference material (airdried). Retention and different penetration parameters showed better figures when only modifying the treating cycle rather than using a pretreatment. Both pretreatments seemed to have no positive effect on the treatability of airdried material. Increasing the strength of the initial vacuum parameters of the full-cell processes improved the degree and homogenity of the penetration of the preservative components.
J Van Acker, M Stevens
The effect of preservative distribution in small blocks of Pinus sylvestris on the toxicity of tributyltin oxide to Reticulitermes santonensis Feytaud
1971 - IRG/WP 206
Small blocks of Pinus sylvestris (50x25x15 mm³) were treated by a full-cell method with various concentrations of tributyltin oxide in benzene. Replicate blocks were then freeze dried, rapidly air dried or slowly air dried and exposed to surface attack by the subterranean moistwood termite Reticulitermes santonensis Feytaud. At all concentrations it was found that the freeze-dried blocks were more heavily attacked than the air-dried ones, and that a threshold value determined in the normal way using air-dried blocks could be much underestimated. This agrees with what one would expect from the uneven distribution of preservative produced by air drying compared with the uniform distribution obtained by freeze drying. The results with slow air drying were in between those obtained from the other two methods. Further work is required to check the value of this method.
M P Levi, D N R Smith
Efficacy of Didecyl Dimethyl Ammonium Chloride (DDAC), Disodium Octaborate Tetrahydrate (DOT), and Chlorothalonil (CTL) against Common Mold Fungi
2004 - IRG/WP 04-30338
The fungitoxic properties of four fungicides, alone and in combination, against four different mold fungi commonly associated with indoor air quality problems were evaluated on two different wood species and sheetrock. The fungicides were chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) (CTL) in a 40.4% aqueous dispersion, disodium octaborate tetrahydrate (DOT) in two different forms - a 40% glycol solution and a 98% wettable powder, and didecyl dimethyl ammonium chloride (DDAC) in an 80% solution. The fungi were Aspergillus niger, Cladosporium cladosporioides, Penicillium brevicompactum, and Stachybotrys chartarum. All fungicide treatments on wood reduced growth, sporulation and discoloration of the mold fungi when compared to nontreated specimens. No single fungicide provided total control of all four fungi on wood. CTL provided the best single-agent protection by totally preventing the growth of C. cladosporioides and S. chartarum and reducing growth of A. niger and P. brevicompactum to low levels. DOT in both forms was very effective against A. niger, but provided only sporadic protection against other fungi. DDAC provided good protection against S. chartarum but was not as effective against the other molds. Combinations of the different biocides were more effective than any single agent. DOT + DDAC totally prevented or greatly reduced growth of A. niger, P. brevicompactum and S. chartarum. Cladosporium cladosporioides was the most difficult organism to control, but even this was achieved when DDAC was increased to 1.0% with DOT. The most consistent control of discoloration, sporulation, and growth of the fungi on wood was obtained with the combination of DOT and CTL. DOT, alone or in combination with DDAC or CTL, was also very effective against the fungi on sheetrock. The results suggest that by using appropriate products, during construction or after water damage, problems associated with the growth of common molds and their potential health effects can be avoided.
J A Micales-Glaeser, J D Lloyd, T L Woods