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"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


Problem of the treatment of dried sawn spruce building timbers with water-borne preservatives. Interim reports for discussion at the 4th Annual Meeting in West Berlin on 27 October 1972
1972 - IRG/WP 311
One of the most difficult technical problems facing the preservation industry is how to improve the treatment of refractory species of timber such as spruce. Its resistance to penetration, even under pressure' precludes its use for more hazardous service situations, and even in less severe conditions a higher level of treatment would be desirable. The importance of this subject led us to look once again at possible ways of improving treatment.
W Liese, J W W Morgan, T Hof, R O Ullevålseter


Treatability of plywood containing intermountain Douglas fir veneers
1982 - IRG/WP 3203
Eighteen sheets of plywood were obtained which contained intermountain Douglas-fir veneers from two regions of British Columbia. Following pressure treatment with chromated copper arsenate (CCA type C) and ammoniacal copper arsenate (ACA) the preservative penetration and retention in individual veneers was assessed. It was concluded from the study that the intermountain Douglas-fir veneer could not be adequately penetrated by either CCA or ACA, although the degree of penetration achieved with ACA was better than that recorded for CCA. The preservative retentions measured were generally in excess of that required for plywood to be used in the preserved wood foundation system.
J N R Ruddick, A Walsh


Water-based wood preservatives for curative treatement of insect-infested spruce constructions
1998 - IRG/WP 98-30171
On laying down sanitation measures for wooden constructions infested by wood boring insects, we must take into account static risks for the construction - and, thus, for the security of the user - as well as risks for humans and environment due to the chemical preservative compounds of the treated wood. Analyses on many roof constructions made with spruce (Picea abies L.) have revealed that Hylotrupes bajulus L. and Anobium punctatum De Geer have not the significance given to them for decennies. That often allows to replace solvant-based with water-based wood preservatives in old buildings, for the protection of humans and environment. Therefore, a method has been developed in Switzerland for testing wood preservatives with delayed curative efficacy against the house longhorn beetle. Like the European Anobium Standard EN 370 this method intends to prevent the emergence of Hylotrupes beetles. Laboratory tests with diverse water-based wood preservatives available on the market in Switzerland have shown that particularly boron and benzoylphenylurea derivatives containing products get a sufficient penetration in the wood and prevent the emergence of the beetles.
E Graf, P Manser, B Lanz


Field tests out of ground contact in France: Definition of the test procedure and preliminary results after 18 months
1981 - IRG/WP 2161
M Fougerousse


The utilisation and preservation of Eucalyptus globulus agricultural stakes from Portugal
1989 - IRG/WP 3520
This paper reviews the development and utilisation of Tanalith C treated Eucalyptus globulus stakes: particular reference is made to their use in vineyards. The treatment characteristics of commercially available stakes will be described and penetration patterns evaluated.
A Milne e Carmo, D A Lewis, A Lyman


Detection of brown rot decay in wood by ion mobility spectrometry
1991 - IRG/WP 2377
A test method for the detection of brown rot decay in wood is described and involves a two-step procedure: thermal release of vapours from wood samples followed by analysis using Ion Mobility Spectrometry (IMS), with results being obtained in 5-10 seconds. The advantages, limitations as well as the detection limit of the technique are presented.
A H Lawrence, T Nilsson


X-ray analysis of selected anatomical structures in copper/chrome/arsenic treated wood
1973 - IRG/WP 320
Application of analytical electron microscopy to problems in wood preservation has been very limited. Indeed, less than ten workers appear to have published their results using the technique, and of these' only two papers deal with energy dispersion procedures in the scanning electron microscope; the others employ the more familiar wavelength dispersive methods of the electron probe.
H Greaves


300 years water-logged wood: Treatability with CCA-C
1998 - IRG/WP 98-40103
The treatability of 300 years water-logged and recent wood (Abies bornmülleriana M.) was assessed by dip treatment and vacuum and pressure cycling with CCA-C. Treatment runs were evaluated on the basis of weight gain retention and radial and tangential penetration measurements. The preservative penetration and retention levels in the 300 years water-logged wood were higher than in the recent wood due to water-logging.
S N Kartal, N Yilgör


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


Anti-stain field trials in British Columbia
1981 - IRG/WP 3174
Four alternative anti-sap stain chemicals were subjected to a four month field evaluation during the summer of 1980. The test, established at a Vancouver Island sawmill, was designed to evaluate the potential long-term effectiveness of sodium tribromophenate (Velsicol Ltd.), Biocom XX (Bramco Industries) containing methylene bis-thiocyanate, Woodbrite NTX (Van Waters & Rogers Ltd.) containing 3-iodo-2-propynyl-butyl carbamate and Mitrol 48 (Kenogard) containing guazatine acetate and quaternary ammonium chlorides, on hemfir and Douglas fir. Sodium tribromophenate was found to give surface protection equivalent to that of chlorophenate treated controls. Biocom XX was also effective, although the active ingredient came out of solution at the required treating solution concentration. Woodbrite NTX and Mitrol 48 were found to be ineffective on either species group under the test conditions.
D V Plackett


Evaluation of the leach resistance and preservative efficacy of novel biocides as surface treatments applied by brush to spruce (Picea abies)
1998 - IRG/WP 98-30170
The comparative leach resistance and preservative efficacy of a number of alternative organic preservatives (available from Zeneca Specialties) and selected commercially available biocides as surface coatings to wood in Hazard Class 3 have been assessed. Two concentrations of test preservatives were applied by brush to Spruce (Picea abies), including formulation and untreated controls. A leaching program was carried out involving the immersion of the treated blocks in water for a scheduled period of time. Blocks were then subjected to biological tests to determine preservative efficacy using the basidiomycetes Coniophora puteana and Gloeophyllum trabeum in a modified EN 113 system; sapstain and mould tests were separately undertaken according to a modified EN 152 test using mixtures of Aureobasidium pullulans and Sclerophoma pithyophila, and Trichoderma harzianum and Trichoderma saturnisporium. Of the four alternative actives tested, one Zeneca development product based on Hexaconazole compared very favourably against the selected commercial biocides tested. An aqueous system based on a Zeneca penetrating aqueous polymer coupled with the Zeneca development active demonstrated favourable performance in relation to an existing solvent based product.
I M Tierney, A Bruce, D C R Sinclair, T Yeates


Practical testing of wood preservatives to prevent weathering damage and infection by micro-organisms on spruce and pine
1989 - IRG/WP 3530
Brush application, is generally used to prevent wooden window frames from decay caused by influence of weathering and fungi. Accordingly 10 boards of pine (Pinus sylvestris) and spruce (Picea abies) were treated with 10 commercially used wood preservatives. The efficiency of fungicides by using chiptest and blue stain test (EN 152), the effectiveness against weathering as well as the course of colonization of microfungi were measured on boards, that had been hurted by sawing. Results after one year's exposure showed that neither the normally required amount of 250 ml/m² nor the effective depth of penetration of the fungizidal equipment had been realized by using brush application. The smaller the permeability of the coating system, the more likely ideal conditions for the growth of fungi (e.g. basidiomycetes) are provided, answering hurtings of the coating and moisture contents of more than 30%. The variety of fungi (on pine 32 and on spruce 17 species) can be a result of anatomical differences and distinguished compounds of the wood species. After 24, respectively 36 weeks of exposure the frequent occurrance of basidiomycetous yeasts (Cryptococcus albidus, Rhodotorula mucilaginosa), blue stain fungi (Aureobasidium pullulans, Hormonema dematioides), Epicoccum nigrum, Alternaria alternata and Phoma species was noted.
R Gründlinger, O Janotta, H Melzer, K Messner


Influence of variable lignin content on brown rot decay of wood
1987 - IRG/WP 1320
Compilation of published data and new experiments with brown-rotting fungi on different timber species suggest that their decay activity, in contrast to soft rot and white rot fungi, is not greatly influenced by the type or amount of lignin present.
T Nilsson, G F Daniel


A behaviour of CCA penetration of fir (Abies bornmulleriana Mattf.) at different ramp times and constant vacuum/pressure applications
2006 - IRG/WP 06-40346
A behaviour of CCA penetration of Bornmulleriana fir (Abies bornmulleriana Mattf.) at different ramp times and constant vacuum/pressure applications was illustrated for the main flow directions by the experimental pictures.
I Usta, R Despot, M Hasan


Effect of double-vacuum and vacuum-pressure impregnation with water-borne preservatives on the dimensional characteristics of spruce
1990 - IRG/WP 3613
Air-dried planed spruce (Picea abies) samples were treated with a water-borne preservative (micro-emulsion) and one oil-borne type both containing azaconazole and deltamethrin. Each set of samples contained equal number of specimens with different growth ring orientation, heartwood content and density. In addition to the preservative retention and the penetration of a.i., the swelling of the samples was measured immediately after impregnation and further after 6, 24 and 48 hours. The growth ring figure induced different uptake levels when the impregnation process was intensified. Gradual increase of tangential surfaces reduced the retention. The effect of the wood properties on liquid absorption seemed to be greater for the oil-borne treatment. Volumetric swelling of the test samples treated with the water-borne solutions ranged from 0,5 to 0,6% immediately after double-vacuum impregnation increasing to a maximum of 0,8% 6 hours later. Subsequent air-drying of treated samples did not produce checking nor deformation. The oil-borne preservative gave rise to a swelling 3 to 4 times less. A swelling of 0,8% for spruce treated with a water-borne preservative may be considered acceptable taking into consideration volumetric movement figures of 1 to 1,5% for tropical hardwood species, classified as low movement timbers.
J Van Acker, M Stevens, G Rustenburg


Washboard effect: A surface deformation of spruce resulting from vacuum-pressure impregnation with water-borne preservatives
1987 - IRG/WP 3450
The washboard effect has been observed in sawn spruce after both commercial and laboratory based preservative treatments and is of increasing economic importance. The effect is defined as a specific phenomenon at the wood surface. It is distinct from internal collapse in the wood, but it may occur in association with internal collapse damage. Experimental investigations on the causes of washboarding and preliminary results indicate that a combination of several factors induce the effect. At treating pressures below about 10 bar washboarding appears to develop with post treatment drying of the wood whereas with higher pressures it will occur during the impregnation cycle. Further research has been started to develop measures to minimise the problem.
H Willeitner, R J Murphy


Performance of treated and untreated sawn fence posts of Scots pine and Norway spruce
2000 - IRG/WP 00-30247
Sawn fence posts are a rather important product and the objective of this trial was to assess their durability. In 1985 a field trial with treated and untreated fence posts of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) was set out at the test field in Ultuna, Uppsala, Sweden. The posts had a dimension of 75 x 100 x 1400 mm3. The preservatives applied were a CCA, an ammoniacal copper and a creosote. In 1991 fence posts of the same species and size were set out at the test field in Simlångsdalen, Sweden and the preservatives used were a CCA and an ammoniacal copper quaternary compound. The assessment showed that all treated fence posts were attacked very little (mean rating 0 - 0.5) during the first 3 - 4 years at the two test sites. After 7 to 8 years the mean ratings were around 1.0 (slight decay). In Ultuna, after 13 years of exposure, the mean ratings are around 2.0 (moderate decay). The mean service life of untreated Scots pine was 10.2 years in Ultuna and 5.4 years in Simlångsdalen and for untreated Norway spruce 7.5 and 3.2 years, respectively.
Ö Bergman


Water-borne wood preservatives against marine borers. Results from NWPC marine trials started in 1972 and 1976
1990 - IRG/WP 4162
The paper presents the results from NWPC (Nordic Wood Preservation Council) marine trials started in 1972 and 1976. The trials are carried out according to the NWPC Standard No. 1.4.2.2./73 "Marine test - a test against marine wood boring organisms in sea water". The test site is Kristineberg Marine Biology Station on the west coast of Sweden. The wood blocks used in the trials were made from sapwood of European redwood (Pinus sylvestris L.). European beech (Fagus sylvatica L.), European birch (Betula spp.) and Norway spruce (Picea abies (L.) Karst) were also used to a minor extent. In all, 19 water-borne wood preservatives were tested. The preservatives consisting of copper-chrome, copper-chrome-arsenic, copperchrome-boron, copper-chrome-phosphorus and tributyltin oxide gave best performance. The ammoniacal copper preservatives failed to protect the wood against marine borers.
Ö Bergman, C Lundberg


Acetylation of lignocellulosic materials
1989 - IRG/WP 3516
A simplified procedure for the acetylation of lignocellulosic materials has been developed. The acetylation is done with a limited amount of liquid acetic anhydride without the addition of a catalyst or an organic co-solvent. Dimensional stability and biological resistance are both much improved by the acetylation. Equilibrium moisture content in acetylated material is considerably lower than in unmodified material. No reduction of bending strength was found for acetylated solid wood samples. The process can be employed for both fibers, wood particles and solid wood. The process is applicable to hardwoods and softwoods, including solid spruce wood, and to non-wood fibers such as jute.
P Larsson, A-M Tillman


Testing method for the treatability of wood
1994 - IRG/WP 94-40031
In order to test and classify the treatability of wood species in pressure treatment processes with water-based solutions, a laboratory method was developed which allows the testing of small samples and limited sections of a stem, e.g. sapwood. The penetration of different liquids was determined separately concerning the three anatomical directions of wood. The common parameters for pressure impregnation were used on sap- and heartwood of eight indigenous and tropical wood species. An elastic epoxy resin proved feasible for coating the samples on five sides. From the data of the testing method a measure for the treatability was calculated, allowing to classify wood species into four treatability classes analogous to prEN 350-2 (1993).
A O Rapp, R-D Peek


Fluoride woodpill
1987 - IRG/WP 3431
Decay problems of spruce joinery in the Netherlands in the 1960's and 1970's led to the introduction of preservative treatment. Because of the known penetration difficulties with Spruce, the results of the treatments were not always successful. The fact that the decay was found only in the joints led to development of the philosophy of "local preservation" of the joints in remedial and preventative treatments, like preservative injections or use of rods and capsules containing preservatives. However the diffusion of the preservatives used in most of these systems is often poor in spruce. Because Spruce joinery dip-treated with bifluorides showed good penetration and protection, a pill consisting of a hydrophylic polymer and bifluorides was developed by TNO. Various laboratory tests carried out with this pill have confirmed good penetration of the bifluorides in the wood and activity against decay fungi.
J W P T Van der Drift, K J M Bonsen


Retention and distribution of copper/chrome/arsenic (CCA) in pressurised sap-displaced UK grown spruce and pine
1986 - IRG/WP 3366
Increment cores were taken from UK grown Scots pine (Pinus sylvestris L.), Corsican pine (Pinus nigra var. maritima Ait), Sitka Spruce (Picea sitchensis (Bong) Carr), and Norway spruce (Picea abies (L) Karst) distribution poles treated by pressurised sap-displacement using a 1.8% copper, chrome, arsenic (CCA) solution. Each increment core was sectioned radially and the copper, chrome, and arsenic content analysed. All four wood species showed a higher CCA content in the outer sapwood which declined radially towards the centre of the pole. The net preservative retention in the outer sapwood of Scots Pine, Corsican Pine and Norway Spruce was in the range 13-23 kg/m³. The CCA content in the outer sapwood for Sitka spruce was low (in the range 4-7 kg/m³). Little longitudinal variation in CCA content occurred along the length of the poles for the four wood species studied. The concentration of the individual CCA components varied in a radial direction. Chrome and Arsenic concentrations were at a maximum in the outer sapwood in all four wood species whereas Copper tended to be in a maximum concentration in the inner sapwood some 20-40 mm from the pole surface. This effect was particularly noticeable in Scots pine and Corsican pine. It is believed that the preservative gradients reported may be important in determining the performance of treated wood and as such should be taken into account when designing predictive tests of the efficacy of preservative treatments.
P D Evans, G M Smith, B King


Moisture condition in treated wood exposed outdoors. A progress report after 5 years
1992 - IRG/WP 92-3720
Wood treated with water-borne preservatives, mainly CCA (copper, chromium and arsenic) and CCB (copper, chromium and boron) is often said to absorb more water than untreated wood. In laboratory tests this statement has not been confirmed (Johansson 1977). In 1986 a project was started to compare water absorption during outdoor exposure between wood stakes of pine, Pinus sylvestris L, and spruce, Picea abies, both untreated and treated with different preservatives. For comparison untreated stakes of different species were included as well as painted pine stakes. Results after 28 months' exposure were reported in IRG/WP/3533, 1989. In this document results after five years are reported.
M-L Edlund


Leaching results of shower test on L-joints with boric acid, bifluoride and TBTO rods
1995 - IRG/WP 95-50051
As part of the EC-project "Improvement of a local preservation process for wood products with reduced environmental impact", TNO has performed a leaching test on L-joints treated with pills with boric acid (Defence corner), bifluorides (Woodpil 55) and TBTO (Woodcap). The L-joints were exposed in an adapted shower test during 10 days, using 70 liters of water per day. The experiment is designed to measure leaching under extreme service conditions. Spruce and pine, painted and unpainted L-joints were compared. In general leaching was the highest in spruce. The L-joints treated with boric acid pills showed the highest leaching, with very small differences between painted and unpainted L-joints. Leaching from fluoride and TBTO treated L-joints was even slightly higher than in painted L-joints. From these results it is suggested, that the active ingredients predominantly leach from the end grains in the open joint area of the timber. A higher water run off rate from longitudinal surfaces in painted L-joints could explain for the higher leaching rate in these samples
P Esser, M J Boonstra, W L D Suitela, A J Pendlebury


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