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L-joint trials: Part 3: Relative performance of a range of preservative products
2002 - IRG/WP 02-30292
Long-term trials using the L-joints described in BS EN 330 and AWPA Standard E9-97 have been in progress at BRE since 1982. This paper records the current assessments of decay of L-joints in trials started between 1982 and 1994 with treatments applied to both Scots pine sapwood (Pinus sylvestris) and spruce (Picea sp.). Data are provided on a range of active ingredients including TnBTO, PCP, acypetacs zinc, azoles, isothiazolones, IPBC and disodium octaborate tetrahydrate.
J K Carey


Comparative response of Reticulitermes flavipes and Coptotermes formosanus to borate soil treatments
1991 - IRG/WP 1486
Eastern (Reticulitermes flavipes [Kollarl]) and Formosan (Coptotermes formosanus Shiraki) subterranean termite workers (Isoptera: Rhinotermitidae) were exposed to borate-treated sand in an indirect exposure tunneling assay in the laboratory. In the ten day assay period, both termite species readily penetrated sand containing 5000, 10000, or 15000 ppm (wt. of compound / wt. of sand) disodium octaborate tetrahydrate (Tim-BorÒ) or zinc borate (Firebrake ZB-FineÒ). With Reticulitermes flavipes, significant mortality (85-93%) resulted from workers tunneling through sand treated with 5000 ppm disodium octaborate tetrahydrate (higher concentrations were also effective), or 15000 ppm zinc borate. Responses of Coptotermes formosanus workers were lesser and more variable, with only concentrations of 10000 and 15000 ppm zinc borate resulting in mortality 70-89%) significantly different from that in the control groups. These results suggest that differences between these two species in tunneling behavior may reduce exposure of Coptotermes formosanus to the borate-treated sand.
J K Grace


Results of chemical analyses in the field of wood preservation in the Bundesanstalt für Materialprüfung
1973 - IRG/WP 321
The results of qualitative and quantitative chemical analyses of wood preservatives are often the basis for evaluating the various works in the field of wood preservation. In the past 10 to 15 years a number of such works was carried out in the Bundesanstalt fur Materialprüfung, Berlin-Dahlem, dealing with the identification and effectiveness of wood preservatives and with methods of wood preservation. Fundamental realisations were made which will be summarised below. It seems advisable to differentiate between inorganic and organic chemical wood preservatives and methods of analyses. These are two distinct fields which differ also with regard to the analytical techniques applied.
H J Petrowitz


A new ground-contact wide-spectrum organic wood preservative: DNBP
1986 - IRG/WP 3358
A new organic wood preservative, which 25 years field tests have proved to be of efficiency and effectiveness comparable to CCA wood preservatives for ground-contact applications, is presented. Physical and chemical tests, supporting the long term field test results as well as indicating the characteristics of this preservative, are also presented.
W E Conradie, A Pizzi


Metal carboxylates for wood pest control
1996 - IRG/WP 96-30109
Metal carboxylates have been used as wood preservatives for more than fifty years. Predominantly salts of naphtenic acids have been commercially applied so far. They have water repellent as well as fungicidal and insecticidal properties. In the last years, metal carboxylates of saturated fatty acids were introduced. Fatty acids with 7-10 carbon atoms already have fungicidal activity by themselves. However, their efficacy is markedly increased in a complex with metal ion such as copper and zinc. This carboxylates are environment friendly and low toxic for humans. We studied fungicidal, insecticidal and termiticidal effectiveness of copper and zinc carboxylates by European standard methods. The strongest fungicidal and insecticidal activity showed copper and zinc naphtenates and copper octanoate. The metal octanoates are soluble in white spirit and, moreover in aqueous ammonia solutions. One day after treatment, the leaching of some carboxylates from wood was very low. These carboxylates did not increase the flammability of treated wood.
F Pohleven, M Petric


Migration of Metals from Douglas-fir Lumber Treated with ACZA or Pentachlorophenol Using Best Management Practices: Preliminary Tests
2005 - IRG/WP 05-50224-4
The potential for migration of preservative components from ammoniacal copper zinc arsenate (ACZA) and pentachlorophenol treated Douglas-fir lumber in non-soil contact exposure was assessed in a simulated rainfall device. Metal levels from ACZA treated wood were elevated for the first 30 minutes of rainfall and then declined sharply. Repeated cycles of rainfall led to declines in initial metal losses suggesting that surface metals were gradually depleted from the wood. Penta losses were also initially high, but then declined at rates related to rainfall level. The results suggest that preservative losses from treated wood in above ground exposures can be predicted.
J J Morrell, Hua Chen, J Simonsen


Investigation of the fixation in wood of chromated zinc chloride and copperised chromated zinc chloride preservatives
1976 - IRG/WP 372
A biological method of evaluating the extent to which CZC and CCZC preparations are retained in wood in terms of the potential protection which they afford against destruction by Merulius lacrymans (dry rot) is given. CCZC is recommended for protection of wood under moderate leaching conditions, while the use of CZC under such conditions is not recommended.
V N Sozonova, D A Belenkov


The influence of formulation on the behaviour of LOSP's during industrial impregnation of spruce
1986 - IRG/WP 3387
Evidence is presented that the comparative behaviour of two LOSP formulations during impregnation treatment of spruce cannot be predicted purely on the basis of their physical characteristics (viscosity, surface tension and contact angle) nor on the extent of their 'passive' penetration into pine sapwood.
L D A Saunders, D M Zuvencko


Water-borne preservative marine trials in Western Canada
1981 - IRG/WP 470
Red pine boards treated with chromated copper arsenate, ammoniacal copper arsenate, copper zinc arsenic additive, a modified ammoniacal copper arsenate, and zinc arsenic additive, have been installed in a marine field test at West Vancouver, British Columbia. After two and a quarter years exposure, all the test samples are in excellent condition with the exception of those treated with the zinc arsenic additive. All the zinc arsenic additive treated boards at the lowest preservative retention and two thirds of those at the second lowest retention in test have failed. A performance index calculated for the zinc arsenic additive indicates an added service life of 3% at the standard retention level.
J N R Ruddick


Preliminary evaluation of borate baits and dusts for eastern subterranean termite control
1990 - IRG/WP 1433
Borates are of potential use in the development of baiting systems for subterranean termite control. In the 15-day laboratory assays reported here, the oral toxicity of disodium octaborate tetrahydrate to Reticulitermes flavipes (Kollar) was evaluated under choice and no-choice conditions. These assays suggest a range of 2500 to 5000 ppm to be applicable in developing baits, and that concentrations greater than 5000 ppm may deter feeding. Laboratory assays with borate dusts (disodium octaborate tetrahydrate, zinc borate, and a fine-grain zinc borate) are also reported. In a toxic variation of mark-release methodology, these materials are passed among the test group by grooming foragers exposed to the dust. In these assays, 10% of the test group was exposed to the borate dust, then released placed in contact with unexposed workers in a simulation of a field release. Zinc borate treatment elicited the greatest mortality (99-100%), although disodium octaborate tetrahydrate also elicited mortality significantly greater than that in the control groups. These results suggest that less soluble borates may be more efficient dust toxicants, and that capture and dust-treatment of a portion of the foraging termite population could elicit high mortality among termites contacting the treated individuals after their release back into the colony.
J K Grace, A Abdallay, J M Sisson


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


A contribution to the adsorption/desorption behaviour of zinc-hexa-fluoro-silicate in different soils
1995 - IRG/WP 95-50056
The estimation of a possible endangering of the groundwater through wood preservatives and thereof deriving measures for the avoidance of secondary damages require among others exact knowledge concerning the behaviour of wood preservative compounds in the soil matrix. Adsorption and desorption behaviour were determined at four soils of different characteristics, which were brought in contact with aqueous solutions of zinc-hexa-fluoro-silicate. For the respective experiments four concentrations were prepared containing 10, 50, 100 and 250 ppm zinc ions. Water of p.a. quality served as reference. As to be expected the soils in question behaved different: the adsorption of inserted ions increased with increasing clay content of the soil. On the other hand significant differences exist also with respect to the adsorption behaviour of the zinc cation in relation to the hexa-fluoro-silicate anion. Within the concentration interval investigated, the same soil adsorbed approximately the same proportional zinc quantity. However, when increasing the hexa-fluoro-silicate-ion concentration a proportional decrease concerning the degree of adsorption was observed. The results show that it is not possible to conclude from partial results achieved with individual preservative compounds to the overall system "wood preservative"-soil and that further investigations are necessary for an inclusive description of the problem.
E Melcher, R-D Peek


Protection of OSB against termites by incorporation of different actives via glue line treatment
2008 - IRG/WP 08-30453
Different organic actives and zinc borate were incorporated into OSB during the manufacturing process to enhance the resistance against termites. Tests according to EN 117 revealed excellent performance of thiacloprid. Other organic actives such as permethrin might be effective when used in higher amounts. Zinc borate failed the test by far.
S Donath, P Spetmann, T Jaetsch, T Zahlmann


A Preliminary Report on the Properties of Engineered Wood Composite Panels Treated with Copper Naphthenate
2005 - IRG/WP 05-40294
This paper reports on our preliminary investigation of the properties of randomly oriented strandboard which had waterborne or powdered copper naphthenate (CuN) incorporated into the board during manufacture. When compared to zinc borate-treated controls (ZnB), the mechanical properties of strandboard (MOR, MOE, work-to-maximum load, internal bond strength) were not adversely affected by treatment with either form of copper naphthenate. In general, values for mechanical properties followed the trend untreated controls > waterborne CuN = powdered CuN > ZnB. Water absorption and dimensional properties followed a similar trend. This preliminary study suggests that CuN is a viable alternative treatment for engineered wood composites.
J W Kirkpatrick, H M Barnes


Leaching and fixation characteristics of chrome-copper-fluoride-zinc (CCFZ) treated wood
1996 - IRG/WP 96-30096
The leaching characteristics of radiata pine sapwood blocks treated with CCFZ were evaluated by the AWPA standard leaching test. The rate of fixation of the preservative components in CCFZ treated radiata pine were also evaluated by quantitative analysis of solution expressed from the treated wood. Both leaching and fixation characteristics of CCFZ were compared with CCA-Type C treated wood samples. The permanence of CCFZ is excellent and comparable to that of CCA-Type C, and the rates of CCFZ fixation were similar to those found for CCA-Type C. These results suggest that CCFZ has a potential as alternative preservative for the replacement of CCA-Type C.
Gyu-Hyeok Kim, Jong-Bum Ra


Corrosion of zinc-coated nails used with preservative-treated western red cedar shakes in service
1982 - IRG/WP 3197
The corrosion of metal fasteners used with certain wood species and with preservative-treated woods can be a serious problem. The chemical reactivity of western red cedar (Thuja plicata Donn) extractives to iron and copper is well documented and wood preservative treatments containing copper, chromium, and/or ammonium hydroxide can be expected to similarly attack some metals. This problem is compounded when red cedar is treated, and, such treatments with CCA and ACA have become customary in current efforts to extend the service life of shingles and shakes. Present recommendations for shake and shingle roof applications specify the use of hot-dipped zinc (iron) or aluminium nails. However, the use of nails made of stainless steel or other alloys of greater cost is advised with preservative-treated wood products.
R S Smith, E L Johnson, A J Cserjesi


Assessment of the toxicity of some copper-, zinc- and boron-based wood preservatives to the cellar fungus Coniophora cerebella Schröet
1974 - IRG/WP 242
This article reports the use of a method based on the determination of the probability of the protection of timber against destruction by fungi. By converting the probability values to probit values and plotting them as a function of the amount of preservative retained in the timber, curves of the toxic effect are obtained, enabling any timber protection probability to be assessed.
V N Sozonova, D A Belenkov


Some data on the activity of alternative fungicides for wood preservation
1985 - IRG/WP 3333
Data from laboratory tests against basidiomycete fungi are presented for 9 alternative fungicides in organic solvent formulations and also in water for one product. Results are compared with data for reference preservatives, tributyltin oxide, copper and zinc naphthenates and pentachlorophenol. Of special interest is the apparently better than additive effect of mixing tributyltin naphthenate and Xyligen B, and the promising performance of Armoblen 480, a novel organic solvent formulation of n-alkyl coco-derived quaternary ammonium compounds.
A F Bravery, J K Carey


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


Durability of Wood Plastic Composites Relative to Natural Weathering and Preservative Treatment With Zinc Borate
2005 - IRG/WP 05-40316
Wood-Plastic Composites (WPCs) used for decking have experienced dramatic increases in North America, averaging 25% growth per annum since 1998. A key factor contributing to this growth has been the successfully communicated message that they are "virtually maintenance free". The common perception being that the wood fiber is completely encapsulated by the thermoplastic resin, minimizing the potential for moisture absorption and inhibiting attack by wood destroying organisms. Recent publications, however, have raised concerns about the durability of WPCs. These studies showed that wood particles close to the surface of WPC products can attain moisture levels high enough to facilitate the onset of decay. Other experiments have shown that preconditioning this material through accelerated laboratory weathering (QUV) or natural exterior exposure to the elements, yielded significant increases in moisture uptake relative to the unexposed samples. The ability of these materials to absorb moisture has been identified as a significant factor in evaluating decay susceptibility in these laboratory tests. We examined moisture uptake in large sized (low surface to volume ratio) and smaller cut (high surface to volume ratio) WPC samples and found a much greater and rapid water uptake in the smaller samples. A soil block decay test with commercially produced unweathered WPC’s resulted in weight losses of between 10-20% (20-40% wood component) in as little as four months time. Effects of exterior weathering on moisture uptake showed increased moisture in samples taken from WPC boards in the field at various locations for 1 to 2 years. A soil block decay test with unweathered and naturally weathered WPCs showed significantly high weight loses in samples that had been in an outdoor exposure in Valencia, Ca for 2 years. Samples from the same exposure test that had been treated with 1.0 or 2.0 % zinc borate showed almost no weight loss.
M E Mankowski, F M Ascherl, M J Manning


Laboratory evaluation of metallic naphthenates as wood preservatives
1991 - IRG/WP 3654
Fungicidal and termiticidal efficacy of copper and zinc naphthenates was appraised according to Japanese standardized laboratory testing methods. Copper and zinc naphthenates succeeded in protecting wood from decay fungi at retentions of 0.5 and 1.0 kg/m³ as metal, respectively. [JIS A 9302 (1976)] when they were applied to vacuum/soak impregnation [JIS A 9301 (1976)]. With respect to the fungicidal performance in superficial treatment, copper naphthenate was sufficiently effective at a treating strength of 2% as Cu and zinc naphthenate was at 3% as Zn after mild weathering cycles prescribed in JWPA Standard 1 (1979). Their termiticidal effectiveness was satisfactory at 1-2% in wood block tests [JWPA Standard 111) (1981)] in which Pine sapwood specimens treated by brushing were exposed to subterranean termites for three weeks.
K Tsunoda, M Sakurai


Tendency of the preservative use for impregnation industries in Japan
1998 - IRG/WP 98-50101-05
In Japan, since 1997, the acceptable limit of the arsenic in the waste water become to 0,1 mg/l and the additional regional severer restriction can be established. In this reason, Japanese wood preservation industries intend to use other than CCA, like DDAC, ACQ, Tanalith CuAz, copper-naphthate and zinc-naphthenate, as replacing from CCA. In Jan-June 1997, the share of CCA preservatives was less than 30% in contradiction to over 90% in Jan-June 1996.
K Suzuki


Timber deterioration and its prevention in marine environment
2005 - IRG/WP 05-10559
Wood-borer activity is an established fact in Mumbai harbour that leads to severe deterioration of timber. In order to prevent the deterioration caused by wood borers three resin preservatives containing Zinc borate, Organo-copper polymer (4 wt% Cu) and Organo-Tin polymer Copoly(TBTM-MMA) were used for timber treatment. Test panels were treated using standard method and their efficacy was tested. It was observed that among three preservatives, panels treated with copoly (TBTM-MMA) with 10kg/m3 remained free from borer attack for 42 months, panels treated with Organo-copper polymer and Zinc borate, incorporated with chlorinated rubber (CR) have protected timber for 8 and 15 months respectively, as compared to control panels which were severely affected within three months. The study revealed that preservative containing TBTM as a toxic moiety can be used as an anti-borer preservative and protect the timber in marine environment over long period.
B S Swami, M Udhayakumar, P Kumar, A B Samui


Corrosion of fasteners in treated wood
1971 - IRG/WP 303
Surveying tests for determining the corrosion rates of some metals and alloys in wood untreated as well as treated have been made. It is shown that ordinary steel corrodes faster than other common fastener metals such as copper, brass, aluminium and stainless steel do. Zinc coatings, however, will prevent the steel corrosion effectively provided that the coatings are thick sufficiently. Catalytic decomposition of cellulose by rusting iron is briefly discussed since the expectation of life for a fastener joint is not only depending on after the corrosion remaining cross-section of the fastener but also from the wood deterioration.
T Wallin


Performance of Paraserianthus falcataria treated with ACZA, ACQ, CC or CCA and exposed in Krishnapatnam harbour, India
2005 - IRG/WP 05-30382
Paraserianthus falcataria (=Albizia falcataria) treated to two retentions with ammoniacal copper zinc arsenate (ACZA), ammoniacal copper quaternary (ACQ), ammoniacal copper citrate (CC) and chromated copper arsenate (CCA) was assessed over 34 months in a tropical marine waters at Krishnapatnam harbour on the east coast of India. ACZA treatment showed comparatively better resistance than CCA, ACQ and CC, while CC provided the least resistance to marine borer attack. Eight species of borers i.e. Martesia striata, M. nairi, Teredo furcifera,T. parksi, Lyrodus pedicellatus, Nausitora hedleyi, Bankia campanellata and B. rochi were recorded on test panels. Of these, M. striata, L. pedicellatus, T. furcifera and B. campanellata were the dominant species, while other species settled sporadically. The results suggest that copper based preservatives are less likely to perform well under extreme tropical exposures without arsenic.
B Tarakanadha, K S Rao, J J Morrell


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