Your search resulted in 46 documents. Displaying 25 entries per page.
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...
H M Barnes, R W Landers, L H Williams
Observations on the colonization of freshly-felled timber treated with prophylactic chemicals by mould and sapstain fungi
1989 - IRG/WP 1394
Field tests using freshly felled pine sapwood were set up to determine the effectiveness of a range of antisapstain compounds and to study the problems of colonization by mould and sapstain fungi. Differences were recorded both in the overall performance of the compounds and also their selectivity in controlling specific fungal types. These results were found to be useful in gaining a better under...
G R Williams, D A Lewis
Efficacy of anhydrides as wood protection chemicals - II. Performance against soft rot fungi
1998 - IRG/WP 98-30174
Pine sapwood modified with various anhydrides and with butyl isocyanate was tested for its resistance to soft rot decay. Small stakes were exposed for 20 months in unsterile soil in a fungal cellar test.
Wood modified with butyl isocyanate performed better than any of the anhydrides tested, with a threshold level of protection (less than 3% weight loss) at 12% weight percent gain (WPG). Stakes ac...
S C Forster, M D C Hale, G R Williams
The identification and preservative tolerance of species aggregates of Trichoderma isolated from freshly felled timber
1992 - IRG/WP 92-1553
The surface disfigurement of antisapstain treated timber by preservative-tolerant fungi remains a major problem in stored timber. Identification of a range of isolates of Trichoderma based on microscopic morphological characteristics was found to be imprecise due to the variable nature of this organism. In addition, studies to compare visual (morphological) characteristics of these isolates with t...
R J Wallace, R A Eaton, M A Carter, G R Williams
Dimensional stabilization of wood with dimethylol compounds
1987 - IRG/WP 3412
This study showed that a substantial degree of dimensional stability can be imparted to wood by crosslinking with low concentrations of dimethyloldihydroxyethyleneurea. It was demonstrated that by selecting the right catalyst system the cure temperature can be reduced to the point that strength loss of the treated wood is minimized....
D D Nicholas, A D Williams
An investigation to assess the feasibility of developing an accelerated laboratory test to determine the abrasion resistance of lesser-used timber species for use in marine constructio
2005 - IRG/WP 05-20317
The paper describes the evaluation of a laboratory-accelerated test to compare the shingle abrasion resistance of current and potential timbers for use in marine construction. Useful results were achieved in 47.5 hours, but identified a number of issues to be resolved for the test to be refined and the subsequent results to be interpreted correctly....
G S Sawyer, J R Williams
Observations on the penetration of preservatives into green timber
1985 - IRG/WP 3335
Differences in the rate and extent of diffusion of MBT and NaPCP-based preservatives following a short dip treatment were observed. The importance of preservative distribution as well as toxicity to the target organisms in governing the ultimate performance of any anti-sapstain compound is discussed....
G R Williams, R A Eaton, D A Lewis
Report of Section 3 2001
2001 - IRG/WP 01-30276
G R Williams
Observations on the failure of anti-sapstain treated timber under non-drying conditions
1990 - IRG/WP 1437
A range of bacteria and yeasts were isolated from antisapstain treated timber and fresh sawdust. Solution samples containing 100 ppm of TCMTB in a nutrient medium were inoculated with these organisms and incubated at 25°C for 5 days. The levels of TCMTB remaining in solution were determined by HPLC analysis after this time. Results indicated high losses of active ingredient for a range of organis...
G R Williams
A note on testing the efficacy of wood preservatives above ground
1995 - IRG/WP 95-20078
A number of test methods have been used to evaluate the performance of wood preservatives in above ground situations. These have included EN 113 tests following natural exposure weathering (NEWT), L-joint or T-joint tests, lap-joint tests, and decking tests. A new test referred to as the A-frame test has been developed and is under evaluation. This is based on a sandwich-type test in which a thin ...
G R Williams, J A Drysdale, R F Fox
The performance of wood preservatives in soil-bed soft rot tests
1993 - IRG/WP 93-20007
Testing the efficacy of wood preservatives in soil is recognised as a fundamental part of the assessment of long-term wood protection in ground contact. Laboratory based tests can provide a hazardous environment in which a preservative can be challenged by a range of micro-organisms. This paper presents the results of tests carried out to investigate the performance of wood preservatives in a wet ...
G R Williams, S Caswell
A natural exposure weathering test for the evaluation of preservative performance
1992 - IRG/WP 92-2400
Natural exposure weathering tests were carried out by externally exposing treated wood samples for varying periodes of time up to 36 months. In the laboratory these samples were assayed for residual preservative effeciveness using Coniophora puteana FPRL 11E. The results indicated a loss in efficacy over and above that determined using artificial ageing procedures such as EN73 (evaporative ageing)...
J Brown, G R Williams
Evaluating the natural durability of a number of lesser known species of Ghanaian hardwoods using a short term laboratory assay
2004 - IRG/WP 04-10540
Resistance of a number of Ghanaian hardwoods to attack by the crustacean Limnoria quadripunctata was assessed by measuring the production of faecal pellets under forced feeding conditions over a two week period. Small sticks of commercially available, lesser known timber species, were leached in seawater for one week then placed in a cell culture chamber with one animal and 4 ml of seawater. At in...
J R Williams, S M Cragg, L M S Borges, B Shayler
Field trials on preserved timber out of ground contact
1978 - IRG/WP 3154
This report describes two different field trials studying the performance of preservative treatments on timber exposed to the weather, but above the ground. Results are presented on the protection afforded against decay, and on the efficiency of water-repellent preservative treatments in controlling the uptake of moisture by the timber. Proposals for a standard field test system are briefly discus...
D F Purslow, N A Williams
Report of Section 3 2002
2002 - IRG/WP 02-30302
G R Williams
Report of Section 3 2003
2003 - IRG/WP 03-30328
G R Williams
Guidelines for “Gareth Williams Scholarship Award”
2007 - IRG/WP 07-60247
IRG Secretariat
Guidelines for “Gareth Williams Award”
2016 - IRG/WP 16-60393
IRG Secretariat
Natural exposure weathering tests: Their role in the assessment of wood preservative efficacy
1993 - IRG/WP 93-20006
Previous work has demonstrated the potential and usefulness of natural ageing procedures in e evaluation of wood preservative efficacy. This results from the combination of physico-chemical influences and microbiological interactions with both substrate and wood preservative. In this paper, results are presented for a range of biocide types. Discussions are centred on the value of natural exposure...
G R Williams, J Brown
Marine exposure assessment of the natural resistance of a number of lesser known species of tropical hardwoods to teredinid and limnoriid borers
2004 - IRG/WP 04-10520
Naturally durable species of timber are used as an alternative to preservative treated timber for marine structures, but many species have not been evaluated for their potential for use in this environment. EN 275 specifies a 5-year test period - too long a period for screening tests to be economically viable. In this study, candidate timber species were selected for testing in the sea on the basi...
J R Williams, S M Cragg, L M S Borges, J D Icely
Observations on the performance of copper-based wood preservatives in fungal cellar (soil-bed) tests
1994 - IRG/WP 94-20047
Fungal cellar (soil-bed) tests are considered to be an important tool for the evaluation of the performance of ground contact wood preservatives. Facilities of this type have been established world wide although caution has been exercised in their introduction into standard testing methods for the approval of wood preservatives. This is the result of concerns over the variability in the biological...
G R Williams, D Rudolph, M E Hedley, J A Drysdale, R F Fox
Comparing the resistance of a number of lesser known species of tropical hardwoods to the marine borer Limnoria using a short term laboratory assay
2003 - IRG/WP 03-10500
Naturally durable species of timber are used as an alternative to preservative treated timber for marine structures, but many species have not been evaluated for their potential for use in this environment. EN 275 specifies a 5-year test period - too long a period for screening tests to be economically viable. In this study, durability was assessed by measuring the production of faecal pellets by ...
L M S Borges, S M Cragg, J R Williams
Efficacy of anhydrides as wood protection chemicals
1997 - IRG/WP 97-30162
Wood samples treated with anhydrides of various compositions have been examined for their decay resistance and moisture behaviour. For this purpose two brown rot fungi (Coniophora puteana and Gloeophyllum trabeum) and two white rot fungi (Trametes versicolor and Pycnoporus sanguineus) were used in conventional and modified soil block tests. The modified soil block tests conformed to the method as ...
S C Forster, M D C Hale, G R Williams
The effect of composition on the effectiveness and fixation of CCA and copper/chrome preservatives. Part 1: Effectiveness. Part 2: Selective absorption and fixation
1973 - IRG/WP 324
A preliminary study of a wide range of copper-chrome-arsenic formulations indicates that the most effective are in the region, CuSO4 · 5H2O - 35 to 45 per cent; K2Cr2O7 - 40 per cent and above; As2O5 · 2H2O - 25 to 15 per cent or less. Effectiveness appears to depend more on the copper content than the copper - arsenic. Observations on selective absorption and leaching suggest that the chromium ...
D N R Smith, A I Williams
Differential susceptibility of living and dead timber to colonisation by sapstain and mould fungi
1998 - IRG/WP 98-10288
Field studies have revealed that when timber is irradiated (i.e. killed) it is more susceptible to colonisation by mould fungi than sapstain fungi. By comparison, freshly sawn timber shows very little mould colonisation, tending to be colonised by sapstain fungi. It appears, therefore that the physiological state of the wood may influence the pattern of colonisation. A laboratory trial was underta...
J R Williams, D J Dickinson, J F Webber