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The use of pressure cycling to improve heartwood penetration in Pinus radiata (D. Don)
1995 - IRG/WP 95-40050
This study investigates the effect of cycling pressure on the treatability of radiata pine heartwood. The results indicate that liquid penetration into the heartwood is affected by the preconditioning method used and pressure treatment time. There is no significant improvement in the penetration of Pinus radiata (D. Don) heartwood when a cycling or pulsation process is used.
P R S Cobham, P Vinden


An investigation of the effects of pre-steaming on the treatment of sawn spruce timber with Celcure A, a copper-chrome-arsenic preservative
1981 - IRG/WP 3150
Difficulties in the treatment of spruce using standard vacuum/pressure techniques with both water-borne and organic solvent preservatives are well known. We have evaluated the influence of steaming on treatability with a waterborne CCA preservative.
C R Coggins


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


An investigation of the effects of pre-steaming on the treatment of sawn spruce timber with Celcure A, a copper/chrome/arsenic preservative
1981 - IRG/WP 3180
Difficulties in the treatment of spruce using standard vacuum/pressure techniques with both water-borne and organic solvent preservatives are well known. The growth characteristics of spruces (Picea spp) make them attractive candidates for forestry schemes. In 1975 the UK Forestry Commission had about 400 000 hectares, about 20% of total UK forest area, planted with Sitka spruce (Picea sitchensis). As an example of the situation in Scandinavia, the growing stock in Sweden consists of about 45% Norway spruce (Picea abies), 38% Scots pine (Pinus sylvestris) and the remainder hardwoods. The importance of spruce as a source of sawn timber in Europe is clear and we are investigating methods of improving the treatment of this timber. As part of the investigation we have evaluated the influence of steaming on treatability with a waterborne CCA preservative.
C R Coggins


Decay evaluation of the effectiveness of a LOSP envelope treatment in eucalypt and meranti heartwoods for window joinery
1996 - IRG/WP 96-30099
The effectiveness and penetration in heartwood boards of an LOSP formulation containing TBTN was examined by determining decay resistance to the white-rot fungus Perenniporia tephropora. Boards, one metre long, of Eucalyptus regnans, Eucalyptus delegatensis, Eucalyptus obliqua and Eucalyptus sieberi were treated, along with boards of 'light' and 'dark' meranti. After treatment, blocks were cut from various positions along the boards, including one block from the end grain. All except the end grain blocks were coated with epoxy on their freshly cut end grain surfaces to ensure fungus attack occurred only through the lateral surfaces. Some of the blocks were left intact or unshaved, while others had 2 mm of surface wood (treated envelope) removed by shaving. Eucalyptus sieberi was the most preservative absorbent species examined, providing a mean retention of 51.2 kg/m³. Eucalyptus obliqua absorbed least preservative (15.7 kg/m³). Eucalyptus regnans, Eucalyptus delegatensis, light and dark meranti absorbed similar amounts of LOSP, giving mean retentions between 24.9-33.6 kg/m³. There was resin bleed from two of the meranti specimens after treatment, whereas no exudate or kino bleed was produced by the treated eucalypts. Perenniporia tephropora was unable to decay the untreated heartwood of both Eucalyptus sieberi, and Western red cedar (Thuja plicata), and produced minor decay in some Eucalyptus obliqua blocks. Untreated blocks of the other timbers were decayed. LOSP treatment improved the decay resistance of the end grain blocks from light meranti, dark meranti, Eucalyptus regnans and Eucalyptus delegatensis, however only light meranti gained significant protection after treatment in blocks cut from the remaining positions along the board.
L J Cookson, A Trajstman


Microwave modification of Yellow Stringybark (Eucalyptus Muelleriana) posts for impregnation with Copper-Chrom-Arsenic (CCA) preservatives
2000 - IRG/WP 00-40185
Yellow Stringybark posts with diameters ranging from 60-100 mm were microwave conditioned using a 60 kW microwave (MW) generator. A substantial improvement in heartwood penetration of preservatives and relaxation of growth stresses was indicated such that there was no split formation following drying of the posts. High preservative absorption of copper-chrome-arsenic (CCA) was achieved ranging from 340-400 L/m3, indicating much improved permeability. Microwave conditioning followed by soaking in creosote resulted in total creosote penetration throughout the cross-section. Creosote uptake ranged from 119-168 kg/m3. Control of creosote uptake was achieved by changing the soaking time.
G Torgovnikov, P Vinden


"Refractory" is a relative term. Incised alpine fir is treatable
1991 - IRG/WP 3670
While certain wood species carry a reputation for being 'treatable' this normally refers to the sapwood. For most Canadian species, heartwood penetration is the major determinant of whether treatment meets Canadian, USA and Japanese standards and in this respect alpine fir turns out to be a treatable species. Alpine fir is the fir component of the Western Canadian spruce-pine-fir species mix. Since it is becoming an increasing component of the production in Northern British Columbia, added-value markets are being sought for this wood species. The study examines its suitability for pressure treatment. A comparison of the heartwood treatability of material from a number of locations showed that, in every case, incised alpine fir heartwood was more treatable than incised lodgepole pine heartwood from the same sawmill. Lodgepole pine is commonly treated in Western Canada. It is regarded as a 'treatable' species and is listed in both the Canadian and USA standards. However, alpine fir was found to be more consistent than lodgepole pine in meeting these standards. It therefore appears that incised alpine fir is eminently suitable for pressure treatment.
P I Morris


Multiple-Phase Pressure (MPP) Process: One-stage CCA treatment and accelerated fixation process. 4. MPP compared with other processes for achieving acceptable treatment of radiata pine heartwood
1998 - IRG/WP 98-40115
Although radiata pine sapwood is very amenable to preservative treatment, it is often difficult to achieve the required standard for heartwood treatment. A preliminary investigation showed that to achieve the NZ Timber Preservation Council minimum penetration requirements for radiata pine heartwood using the Multiple-Phase Pressure (MPP) Process, a hydraulic pressure of at least 1250 kPa for 20 minutes was necessary. Based on these observations, a further trial was undertaken to compare treatment quality of conventionally kiln-dried radiata pine using Bethell, Modified Bethell and MPP processes. All processes resulted in complete sapwood penetration but a marginally better penetration of heartwood using the MPP process than with Bethell- or Modified Bethell schedules. Both the MPP and Bethell processes had lower retention variability in mixed charges of sapwood and heartwood when compared with a Modified Bethell process.
K Nasheri, J A Drysdale, G Durbin, M E Hedley


Penetration and absorption of water-borne preservatives in conifers from the Western United States: A preliminary report
1988 - IRG/WP 3475
The treatment of most softwoods from the western United States with waterborne chemicals poses a major challenge. Although many of these species are commercially treated with waterbornes, there is considerable debate about their treatability. At present, there is little or no information on the treatability of western wood species with waterborne chemicals. The lack of accurate treatability information related to current practices makes it difficult to improve treatment processes. To develop this information, the heartwood and sapwood of three western wood species were treated using five chemical formulations. Included in these tests were oxide and salt formulations of chromated copper arsenate as well as chromated copper borate. Retentions were measured by gross absorption while penetration was measured using chrome azurol S for copper, cucurmin/salicylic acid for boron, and ammonium molybdate/O-anisidine/stannous chloride for arsenic. The results are discussed in relation to future research directions.
S Kumar, J J Morrell


Influence of Grain Direction on Penetration, Retention, and Leaching of CCA(C) in Sapwood and Heartwood of Kenyan-Grown Eucalyptus saligna and Acacia mearnsii
2007 - IRG/WP 07-40383
Penetration, retention, and leaching of CCA (C) in relation to grain orientation were tested in small (50mm x 50mm x 200mm) sapwood and heartwood samples of Eucalyptus saligna and Acacia mearnsii. In both sapwood and heartwood of the two species, the results showed a consistent pattern: Transverse > Radial > Tangential. Whereas penetration, retention, and leaching were significantly high in the transverse grain direction for both species, magnitudes recorded for radial and tangential grain orientations were low. However, radial conductivity appeared to be consistently better that tangential conductivity of the preservative. Compared to the results for sapwood, penetration, retention, and leaching were significantly lower in heartwood samples of both species. It was noted that in heartwood samples of both species, percent leaching of the preservative was higher than in sapwood samples, irrespective of grain orientation. That was attributed to the high lignin contents in heartwood of E. saligna and A. mearnsii interfering with the fixation of CCA elements. High penetration of the preservative in the transverse grain direction is because of higher conductivity through large interconnecting vessels in the two species. Radial and tangential conduction relied on low volumes of parenchyma cells (rays) and small vessel and fibre pits. Low fluid conductivity in heartwood is mainly due to anatomical, physical and chemical changes that accompany transformation of sapwood to heartwood, hence low void spaces for preservative penetration. From the results, it becomes apparent that different treatment schedules must be worked out for effective treatment of posts and poles of E. saligna and A. mearnsii (where only an outer sapwood envelope treatment is required), and for sawn material with transverse, radial, and tangential faces exposed, in which case treatment would have to be evenly balanced.
R Venkatasamy


Influence of Grain Direction on Penetration, Retention, and Leaching of CCA(C) in Sapwood and Heartwood of Kenyan-Grown Cupressus lusitanica and Pinus patula
2007 - IRG/WP 07-40384
The influence of grain orientation on penetration, retention, and leaching of CCA (C) was tested on small samples of sapwood and heartwood of Cupressus lusitanica and Pinus patula. Samples measuring 50mm x 50mm, and 200mm in the longitudinal axis were sealed to expose only transverse, or radial, or tangential faces, pressure treated with 6% CCA (C), and penetration, retention and leaching of the preservative measured. Generally, the normal trend of Transverse > Radial > Tangential was observed for penetration, retention and leaching in sapwood and heartwood of both species, and in the three grain directions. Penetration in sapwood samples of both C. lusitanica and P. patula were higher than in heartwood samples, being significantly higher in the transverse grain direction. Both retention and leaching reflected on the depth of penetration of the preservative in samples. Retention was generally lower in the three grain orientations in both sapwood and heartwood of C. lusitanica samples. However, it was noted that retention in the radial and tangential grain directions in sapwood and heartwood of both species were not significantly different. Leaching followed the same patterns as for penetration and retention, that is lower in both sapwood and heartwood samples of C. lusitanica, being high in the transverse grain direction in sapwood and heartwood of both species, low in the radial, and lowest in the tangential grain directions. However, leaching in the radial and tangential grain orientations in heartwood samples of both species were fairly similar. Generally, P. patula samples achieved higher penetration and retention, but amounts of the preservative leached out were also higher. The results of the work clearly shows that sapwood, heartwood, and grain orientation all influence penetration, retention, and leaching of CCA (C) in two species of softwoods tested, and that is likely to be the case with most softwoods. The implications on treatment schedules have to be considered.
R Venkatasamy


Effects of planning and sanding on penetration and retention properties of some softwood species treated with copper azole
2008 - IRG/WP 08-40410
This work investigates the effect of some woodworking treatments on penetration and retention properties of four different (scotch pine—SP, Siberian scotch pine—SSP, Siberian larch—SL, and oriental spruce—OS) heartwood species with the waterborne preservative copper azole (CBA-A). A 2.4% active ingredient solution of CBA-A was applied for use in vacuum/pressure treatment of the heartwood samples. Two different woodworking treatment were used, namely planning and sanding. Maximum and minimum penetration values were measured as percentage of cross-sectional area. Penetration of preservative was also determined by X-ray fluorescence spectroscopy analysis (ASOMA). SP resulted in the highest penetration and retention values complied requirements stated in the American Wood Preservers’ Association (AWPA) standards. Siberian scotch also showed satisfactory results for standard requirements. SL and OS showed lower penetration and retention results than those of pine samples which can be related to their refractory characteristics. On the other hand, woodworking treatments such as planning and sanding done before impregnation process did not affect total preservative and copper retention, moreover, interestingly increased preservative retention of the wood specimens in most variations.
Ü C Yildiz, S Yildiz


Investigations concerning liquid absorption of six heartwood species
2013 - IRG/WP 13-40618
In order to determine the liquid absorption and the penetration different heartwood species were treated with a boric acid containing solution. Heartwood of six wood species (Fir, Spruce, Douglas fir, Scots Pine, Oak and Black locust) were used in these investigations whereby the dimension corresponds to the EN 252 format. One half of the stakes were end sealed before treatment. All stakes were impregnated by means of two vacuum pressure processes whereby the short process lasts two hours and long one 24 hours. Retention was determined by weighing while penetration of boron was measured using a two component system consisting of salicylic acid and cucurmin. Following ranking regarding the retention was found independent of test parameters: Fir >> Scots Pine > Douglas fir  Oak  Spruce >> Black locust It could be shown that remarkable higher retentions were determined for Douglas fir compared to Black locust although both heartwoods are classified as “extremely difficult to treat” according to DIN EN 350-2 (1994). From the practical point of view it is recommended that information concerning penetration as well as liquid absorption should be published together in future.
E Melcher, J Zwiefelhofer


Penetration pathway of oilborne preservative in heartwood of Japanese larch (Larix kaempferi)
2019 - IRG/WP 19-40886
The liquid permeability of Japanese larch (Larix kaempferi) wood is extremely low, especially in the heartwood. It is difficult to achieve the penetration of wood preservatives, which is specified by standards, with pressure treatment of waterborne preservatives. Recently, the protection treatment with an oilborne preservative called “deeper penetration treatment” is commercially available, which achieve enough penetration even in the larch heartwood. In this method, the oilborne preservative is only sprayed to incised materials with some post-treatments. To find out the penetration mechanism of the deeper penetration treatment, we tried to visualize the penetration pathway of the oilborne preservative using the larch heartwood samples with and without pre-steaming. The pieces of larch heartwood, which were soaked the oilborne preservative colored with Sudan black B and the water colored with acid fuchsin under atmospheric pressure, were observed with a stereo microscope and a light microscope. The affinity between the larch resin and the oilborne preservative was investigated by mixing them. The acidic fuchsin aqueous solution hardly penetrated into the larch heartwood. The oilborne preservative colored with Sudan black B relatively well penetrated into the samples. The penetration traces of the oilborne preservative were observed in the lumen of tracheid, ray parenchyma, ray tracheid, and inside the axial and radial resin canal. Many of them were observed in the latewood and inside the axial and radial resin canal. The oilborne preservative quickly reached the opposite side through the axial resin canals connecting to the opposite side. The affinity between the resin and the oilborne preservative was high. It is thought that the oilborne preservative traveled quickly through the resin canals as the penetration route. The results of our present study indicate that the resin canal network is one of the factors of the high permeability of the oilborne preservative in larch wood.
H Shibui, T Miyauchi, T Shigeyama, M Ikeda, Y Sugai


Solvent drying and preservation of timber
1977 - IRG/WP 381
Processes which combine drying and preservation are first reviewed. Some preliminary experiments are then described in which blocks of green Sitka spruce sapwood were immersed, in a solution of tributyltin oxide (TBTO) in methanol at 60°C. Satisfactory penetration of the preservative and exchange of methanol and water occurred in a few hours. The methanol was removed rapidly from the wood by evaporation. Satisfactory penetration of TBTO into initially methanol-saturated samples occurred in a similar period. The factors influencing. such treatments are discussed. High initial moisture content of the wood and a high operating temperature are particularly desirable. Some aspects of the possible commercial operation of the process are discussed.
J A Petty


Wood preservatives: Field tests out of ground contact. Brief survey of principles and methodology
1976 - IRG/WP 269
This paper contains the following spots: 1.: The general need for field tests. 2.: Interests and limits of field tests in ground contact. 3.: Various methods in use for out-of-ground contact field tests. 4.: Fungal cellar tests are they an alternative to above-ground decay exposure tests? 5.: Conclusions.
M Fougerousse


Utilization of curcumin for detection of presence of boron in wood
1982 - IRG/WP 3191
It has been shown that curcumin is not a reliable reagent for detecting boron in wood that has been attacked by fungi
M-L Edlund


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


Soft rot penetration - Effect of groundline maintenance treatment on poles in sevice
1983 - IRG/WP 3263
R S Johnstone


Natural durability transfer from sawmill residues of white cypress (Callitris glaucophylla). - Part 3: Full penetration of the refractory sapwood of white cypress
2000 - IRG/WP 00-40167
The heartwood of white cypress, Callitris glaucophylla, is renowned for its termite resistance and durability against decay. The sapwood, which can represent up to 30% of log volume, is non-durable and refractory to conventional preservative treatment. Previous work ascribes the lack of permeability to oily deposits within tracheids and ray cells. Environmental scanning electron microscopy was used to investigate ultrastructural aspects of sapwood permeability. Several pre-treatment processes to improve permeability were tested with limited success. Solvent drying allowed preservative penetration but damaged the structure of the timber. Neither, long term water soaking nor an oscillating pressure/vacuum cycle had any effect on porosity to water-borne treatments. Through extensive modifications to a standard VPI process we can now repeatedly achieve full penetration with organic solvent-based wood preservative solutions into white cypress sapwood. Effects of this process on the strength of the timber are being evaluated. Work is continuing as to the most effective and efficient treatment schedule and the latest results will be presented at IRG 31.
M J Kennedy, L M Stephens, M A Powell


Effect of medium-term degradation of beech wood by erosive (Phanerochaete chrysosporium) and lignin-selective (Ceriporiopsis subvermispora) strains of white rot fungi on its selected physical properties
2004 - IRG/WP 04-40292
At the Faculty of Wood Sciences and Technology a fungal delignification of normal and tension beech wood by erosive and lignin-selective strains white-rot fungi has been studied. The pre-treatment of both kind of wood samples was accompanied by partial delignification and apparent changes of their physical properties influencing the polar liquids penetration.
R Solár, S Kurjatko, M Mamonová, J Hudec


A case study on quality control on telephone poles as a cost saving tool in Tanzania
1987 - IRG/WP 3418
A sample of 28 CCA treated Eucalyptus poles from a lot of 2,000 poles awaiting delivery to the field, was studied to reveal the quality of treatment. Results showed a product of very poor quality. Average figures for penetration and retention were 8.4 mm and 2.2 kg/m³; these results are 66% and 91% below the required standards, respectively. Consequences of such results are estimated to amount to losses of billion of shillings.
K K Murira


A proposal for an international wood preservation standard
1994 - IRG/WP 94-20031
Two factors are driving the need for an international wood preservation standard. First, the global need to use our natural resources more wisely and second, the movement towards free trade exemplified by the General Agreement on Tariffs and Trade. The International Research Group on Wood Preservation is the ideal organisation to undertake the task of developing such a standard. This paper is intended to start this process. It attempts to bring together the best points of a number of national and international standards into a uniform format. Preservative penetrations and retentions for each commodity would be based on the hazard class/use category, the climate zone, the biological area, the natural durability of the heartwood of the species used, the service life required and the consequences of failure. The outline standard presented borrows heavily from the new European Standard and is presented as a possible starting point for the development of an international standard.
P I Morris


Principles and procedure of the planeing test
1981 - IRG/WP 2162
Small end-sealed samples of pine-sapwood (1.5 x 2.5 x 5 cm³) are treated by brushing and afterwards different parts of the treated surface are removed. The remaining part of the sample is tested against either insects or fungi. If no attack occurs sufficient amounts of biocides have been penetrated at least beyond the zone which has been removed. In spite of some problems the test seems the only suitable method, to evaluate organic solvent preservatives, mainly those containing resins, for simple treating methods.
H Willeitner, M Gersonde


Chemical compounds from Eperua falcata and Eperua grandiflora heartwood and their biological activities against wood destroying fungus (Coriolus versicolor)
2005 - IRG/WP 05-30373
The chemistry analysis of the compounds present in dichloromethane and ethanolic fraction as well as bioassays enables to understand the durability differences of Eperua falcata and Eperua grandiflora. The principal distinction between these two species is the acidic subfraction of diterpenoic extract, which is antifungic in Eperua falcata when tested in in-vitro conditions. This study also enables to show that ethanolic fraction plays an important role in the mechanism of natural durability. It also reports the first isolation of cativic acid in Eperua falcata wood.
N Amusant, C Moretti, B Richard, E Prost, J M Nuzillard, M-F Thévenon


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