Your search resulted in 10 documents.
Corrosion of fasteners in heat-treated wood – progress report after two years’ exposure outdoors
2005 - IRG/WP 05-40296
The corrosion of common fastener materials now in use - mild steel, zinc-coated steel, aluminium and Sanbond Z-coated steel – has been evaluated after two years’ exposure outdoors in untreated and heat-treated spruce (Picea abies) respectively. Spruce from South-western Sweden was used. The heat-treatment was carried out in Finland according to the ThermoWood process at a maximum temperature of 220 °C for five hours. The results so far show that the corrosion of fasteners in heat-treated wood according to the particular specification is more severe than in untreated wood. Mild steel and zinc-coated steel has been most susceptible. Stainless steel is hardly attacked at all.
J Jermer, B-L Andersson
Investigation of some technical properties of heat-treated wood
2003 - IRG/WP 03-40266
The objective of this study was to investigate some technical properties of heat-treated wood. Wood heat-treated according to a process intended for wood in above-ground end-uses (European hazard class 3) was subject to the following: · A delamination test according to EN 391 with glulam beams made of heat-treated pine (Pinus sylvestris) and spruce (Picea abies) laminations, assembled with PRF and PVAc adhesive respectively. · Determination of the withdrawal load for screws and nails. · Determination of the emission factor for VOC and the identification of major compounds. Results: · PRF adhesive performed very well whereas PVAc adhesive showed an unacceptable percentage of delamination and thus seems to be unsuitable for gluing heat-treated wood. · There is an indication that the withdrawal load for heat-treated wood is generally lower than for untreated wood. However, the number of tests carried out was quite small and definitive conclusions are difficult to draw. · The emission factor for the heat-treated wood, expressed as TVOC, was less than 10 µg/(m2 x h) and this was less than for untreated reference.
C Bengtsson, J Jermer, A Clang, B Ek-Olausson
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.
Timber preservatives and corrosion
1983 - IRG/WP 3228
A survey of preservative treated timber commodities has illustrated problems that may be caused by corrosion. After treatment, timber should be compatible with commonly used fasteners. Whilst many corrosion methods have been used in the past, no standardized method is used by workers in timber preservation. The Queensland Department of Forestry is developing laboratory test methods for assessing corrosivity of timber preservatives and treated timber. These methods will be followed by in service trials.
R I Davis
Metal plate fasteners in trussed rafters treated with preservatives or flame retardants - corrosion risks
1977 - IRG/WP 3104
In designing roof trusses employing metal plate fasteners it is generally assumed that the roof will remain dry in service. Whilst this is generally true, damp conditions do arise under some circumstances, although it is not possible to quantify the extent of the risk. It is only possible, therefore, to give general recommendations which must be interpreted in the light of local experience of service conditions and site practice. Under severe conditions in the presence of moisture and salts, zinc coatings may not afford long-term protection against the electrochemical processes described above, and suitable precautions must be taken to minimise degradation. Moisture control is the most effective way of avoiding corrosion and if this can be achieved at all stages of manufacture, storage, and use, no diffculties should be encountered. If CCA treatments are employed, time must be allowed for the 'fixation' reactions to be completed before the plates are pressed into the timber. In cases where the assembly may become wet organic solvent preservative treatments are to be preferred in conjunction with metal fasteners. Those formulations which contain water-repellents will give added protection. Salt based flame retardant treatments should not be used in conjunction with fasteners, as the potential corrosion risk is too high. Connector plates manufactured from stainless steel may be considered for use in high-hazard situations. Finally, it has been shown at PRL that the use of nonconducting plastic coatings on the plates confers very considerable durability on these products, which may then be used successfully over prolonged periods under very adverse conditions. Such an approach may be well worth consideration in certain situations and further information on this method can be obtained from Princes Risborough Laboratory. This paper has been produced with the co-operation of the Agrement board, the International Truss Plate Association and the British Wood Preserving Association.
R A Laidlaw, L C Pinion
Corrosion of metal fasteners in contact with copper preservative treated wood
2007 - IRG/WP 07-20370
The corrosion rates of metal fasteners in contact with alkaline copper quat (ACQ) treated wood with or without commercially available water repellent was compared to that of cedar. In this experiment, fasteners were sandwiched between two pieces of treated wood and exposed to a humid environment at a slightly elevated temperature. The use of a “sandwich” design allowed periodic examination of the metal fasteners, which were exposed to the typical chemical loading found at the surface of treated wood. During the experiment, visual observation, weight loss, and diameter loss were used to evaluate the corrosion rate. A one-way ANOVA analysis, confirmed that Stainless Steel 304 provided the best corrosion resistance and a common bright nail provided the worst corrosion resistance, in contact with either copper preservative treated wood or western red cedar. However, the performance of individual coated fasteners in copper preservative treated wood and western red cedar were insignificant on corrosion rate (P<.0001) at the 5% significance level. In a comparison of the wood samples, copper preservative treated wood are approximately two times more corrosive to metal fasteners compared to western red cedar.
BaekYong Choi, J N R Ruddick
Furfurylated wood – withdrawal load for fasteners
2007 - IRG/WP 07-40381
The withdrawal load for hot dip galvanized nails and chromated decking screws in furfurylated Baltic redwood (Pinus sylvestris) with a Weight Percent Gain (WPG) of approximately 40 % was measured according to DIN 1052. The average withdrawal loads were 60-100 % higher for the nails and approximately 20 % higher for the screws in the furfurylated wood compared to untreated wood. The results indicate that the withdrawal load is considerably higher for furfurylated wood (with approximately 40 % WPG) than for untreated wood. The main explanation for this is the higher density of furfurylated wood compared to untreated wood.
J Jermer, A Clang
Performance of Fasteners in Treated Wood: A Comparative Study
2009 - IRG/WP 09-40465
Fastener performance is an important property for treated wood. Published data on screw and nail performance for different preservative systems currently on the market are, however, limited. In this study, screw and nail withdrawal strength for southern pine wood treated with ACQ (above ground and ground contact), MCQ (above ground and ground contact), borate (disodium octaborate tetrahydrate – DOT), and untreated southern pine control were tested at air dry and water-soaked conditions based on ASTM standard D1037. Individual sample density and surface hardness were also measured. The relationship among screw and nail withdrawal strength, density, hardness, and moisture content was established for various preservative systems.
Q Wu, T Shupe, J Curole, K Ragon, M Voitier, M Freeman, D Ring
Corrosion of fasteners in heat-treated wood – progress report after nine years’ exposure outdoors
2012 - IRG/WP 12-40601
The corrosion of common fastener materials now in use - mild steel, zinc-coated steel, aluminium and Sanbond Z-coated steel – has been evaluated after nine years’ exposure outdoors in untreated and heat-treated (thermally modified) spruce (Picea abies). Spruce from south-western Sweden was used. The heat-treatment was carried out in Finland by Stora-Enso Oy according to the ThermoWood process at a maximum temperature of 220 °C for five hours. The results so far confirm the findings after two years’ exposure that the corrosion of fasteners in heat-treated wood according to the particular specification is more severe than in untreated wood. Mild steel and zinc-coated steel has been most susceptible. Stainless steel is hardly attacked at all.
J Jermer, B-L Andersson
Corrosion of fasteners in furfurylated wood – final report after 9 years exposure outdoors
2017 - IRG/WP 17-40810
The corrosion of some common fastener materials – mild steel, stainless steel, zinc-coated steel, brass and Sanbond Z (nickel, zinc and chromate) coated steel – has been evaluated after nine years exposure outdoors in untreated Scots pine and furfurylated beech and southern yellow pine (SYP). The furfurylation was carried out according to a process that resulted in approximately 40 % WPG (Weight Percent Gain). The results show that the corrosion of fasteners in furfurylated wood according to the particular specification is considerably more severe than in untreated wood and very similar to the corrosion caused by thermally modified wood. Mild steel and zinc coated steel has been most susceptible. Stainless steel has not been attacked at all and is therefore strongly recommended for furfurylated wood in outdoor applications.
J Jermer, B-L Andersson, J Schalnat