Your search resulted in 30 documents. Displaying 25 entries per page.
Proposal for further work on accelerated ageing
1988 - IRG/WP 2314
M-L Edlund
Reticulitermes (Ins., Isopt.) in Central and Western Europe
1969 - IRG/WP I 5A
Reticulitermes flavipes (Kollar) has established itself in Hamburg and Hallein coming from the east of North America. In France, on the northern boundary of termit occurrence, Reticulitermes santonensis are distinguished from Reticulitermes lucifugus by special activity and resistance. According to comparative investigations with colonies of several Reticulitermes species of different origins rega...
G Becker
Reticulitermes (Ins., Isopt.) in Mittel- und West-Europa
1969 - IRG/WP I 4
In Hamburg und Hallein hat sich Reticulitermes flavipes (Kollar) aus dem Osten von Nordamerika eingebürgert. An der Nordgrenze des Termitenvorkommens im Westen Frankreichs zeichnet sich Reticulitermes santonensis Fetaud gegenüber Reticulitermes lucifugus durch besondere Aktivität und Widerstandsfähigkeit aus. Nach vergleichenden Untersuchungen an Kolonien verschiedener Reticulitermes-Arten meh...
G Becker
Influence of storage on mould susceptibility of wood at relative humidity values lower than 100%
1989 - IRG/WP 1413
It is well known that wood material changes with time because of different environmental influences. The effects of such changes on the subsequent mould susceptibility are less known. In this paper we report on increased mould susceptibility of pine wood after storage. Mould growth was detected by indirect methods....
J Bjurman
Maintaining the adoption of the equilibrium moisture content in timber by bifluorides under outdoor circumstance
1989 - IRG/WP 3541
A description is given of the practical application of bifluorides, f. ex. Diffusec in maintaining the adaption of the equilibrium moisture content in timber, as a result of a many years observation of treated timber under outdoor circumstances....
H F M Nijman
Methods for testing fumigant efficacies against termites
1986 - IRG/WP 1297
Methodologies for testing fumigants against termites are reviewed and factors needed to be taken under consideration for standardization listed. Toxicity should be defined by both direct exposure to the gas and under more practical "barrier" conditions which include test enclosures simulating abiotic surroundings of the termites, i.e. wood, nest material, etc. To observe latent effects, mortality ...
N-Y Su, R H Scheffrahn
Moisture condition in treated wood exposed outdoors. A progress report
1989 - IRG/WP 3533
Wood treated with water-borne preservatives, mainly CCA (copper/chromium/arsenic), CCB (copper/chrome/boron) or CC (copper/chrome) is often said among users in Sweden to absorb more water than untreated wood. In laboratory tests this statement has not been confirmed but no field tests have been carried out in Sweden to study this phenomenon. In 1986 a project was started to compare water absorptio...
M-L Edlund, C E Sundman
ATP assay for the determination of mould activity on wood at different moisture conditions
1992 - IRG/WP 92-2397
To determine fungal responses to fungicides and environmental conditions and for detection of microbial activity in wood, sensitive and objective methods are needed. We have developed a suitable assay based on analysis of adenosine triphosphate (ATP) by using the luciferin-luciferase reaction. With the aid of this assay the activity of Penicillium brevicompactum on wood at different RH levels was ...
J Bjurman
Preliminary studies to assess the effects of aeration and lowered humidity on the decay capacity, growth and survival of the dry rot fungus Serpula lacrymans (Wulf ex. Fr.)
1997 - IRG/WP 97-10208
Novel microcosms were used to test separately the effects of aeration and humidity on the decay capacity, linear spread and survival of Serpula lacrymans. The application of a pumped air supply resulted in an effective cessation of fungal activity when all but the lowest of the air flow rates was used. Furthermore, the lowest air flow rate caused marked growth tropisms away from the stress. In sep...
G A Low, J W Palfreyman, N A White, H J Staines, A Bruce
Limiting Conditions for Decay in Wood Systems
2002 - IRG/WP 02-10421
Hygrothermal models can predict temperature and moisture conditions in wall components subjected to real weather data, but specific data and a fundamental understanding of how temperature and wood moisture content dictate the progression of decay under these conditions is required for modellers to predict consequences of decay on building performance. It is well understood that wood will decay abo...
P I Morris, J E Winandy
Models of the critical time of humidity and temperature conditions for the development of mould fungi in pine and spruce sapwood
1995 - IRG/WP 95-20066
Regression models of the time factor for the growth of mould fungi in pine and spruce sapwood are studied. The first group of models are based on the results of exposures of mould fungi in static humidity and temperature conditions indicating the time for the start of mould growth in wood. The second group of models are based on the exposures of mould fungi in fluctuating or alternating humidity a...
H Viitanen
Methods of culturing Lyctidae
1980 - IRG/WP 1126
Members of the tropical countries in the IRG Sub-Group "Insects in dry wood" requested a paper on the breeding of lyctids. Compared with other wood boring insects, such as cerambycids and anobiids, the breeding of lyctids is not as difficult and time consuming. Nevertheless some basic principles have to be observed in the laboratory to obtain successful cu·ltures. It is the intention of this repo...
H Kühne
Effect of humidity fluctuations on mould growth on pine wood
1989 - IRG/WP 1412
Most studies on mould development on wood material have been made at constant moisture conditions during the experimental period. As a consequence of such studies, a maximum permittable humidity level to avoid mould problems in wood constructions has been recommended. In the practical situation, the constructions are seldom subject to constant humidity or temperature. In the present paper, we repo...
J Bjurman
Effect of substrate type and moisture requirements in relation to colony initiation in two carpenter ant species
1999 - IRG/WP 99-10320
Conditions necessary for optimal colony initiation or the rate of initial colony expansion by early brood in the carpenter ant species Camponotus modoc and C. vicinus on various substrates conditioned to different moisture contents were studied. Camponotus modoc and Camponotus vicinus queens were placed in Douglas-fir, western red cedar and Styrofoam® blocks conditioned in sealed chambers at 70% ...
M E Mankowski, J J Morrell
The loss of insecticidal action from synthetic pyrethroid-treated wood samples: The effect of high temperatures and relative humidities
1992 - IRG/WP 92-1569
This paper describes the results from bioassays using Hylotrupes bajulus, and chemical analyses, of pyrethroid-treated wood samples following storage for up to 3 years. A range of four storage environments was used consisting of combinations of two temperatures (20°C and 40°C) and two relative humidities (60% and 90%). It is concluded from the chemical analyses that, although losses at room temp...
R W Berry, S J Read
Effect of humidity and temperature on fastener withdrawal resistance from CCA and ACZA treated Douglas-fir
2000 - IRG/WP 00-20209
The effects of preservative treatment on fastener withdrawal was investigated in Douglas-fir lumber conditioned to two moisture regimes. In general, conditioning samples to 19% moisture content produced more substantial changes in withdrawal resistance of galvanized fasteners than did conditioning to 12%. Treatment had little or no effect on withdrawal resistance of stainless steel fasteners. With...
Sung-Mo Kang, J J Morrell
Mould growth and permeability in relation to wet-storage
1989 - IRG/WP 1414
The positive influences of wet-storage of roundwood to avoid attack by blue stain fungi and insects and to avoid cracking of wood during storage are well documented. Comparatively little information is, however, available on the effects on microbial susceptibility of the material after the storage period. The permeability of the wet-stored and the non-wet-stored material was determined. Wood block...
J Bjurman, E L Holappa
Copper fixation in ACQ-D treated Chinese fir at various temperature and relative humidity conditions
2007 - IRG/WP 07-30436
In this study, the effect of different conditions of temperature, relative humidity, and duration of post-treatments on accelerating copper fixation in ACQ-D treated Chinese fir wood blocks was investigated. The conditions include the combination of three temperatures (21, 50, and 70?) and two relative humidity levels (20% and 80%), also include four temperatures (50, 70, 90, and 110?) without con...
Jinzhen Cao, Lili Yu
Evaluation of exposure conditions for wooden facades and decking
2009 - IRG/WP 09-20408
During their functional life, building components are exposed to moisture and other environment stress conditions in numerous ways. This is a fact that should be taken into account during manufacture, product development, designing and work execution of building components. For wood material, moisture stress and biological factors like mould and decay fungi are often critical in cladding and decki...
H Viitanen, T Toratti, R Peuhkuri, T Ojanen, L Makkonen
Modelling of onset of mould growth for wood exposed to varying climate conditions
2009 - IRG/WP 09-20414
A performance-based service life design format based on climatic exposure on one hand and “resistance” of wood against mould growth on the other hand, is presented in this paper. A limit state for onset of mould growth is defined as the occurrence of traces of mould observed by microscopy. A dose-response model is proposed by which onset of mould growth can be predicted for an arbitrary climat...
S Thelandersson, T Isaksson, A Ekstrand-Tobin, P Johansson
Onset of mould growth – the effect of climate variability and different geographic locations
2010 - IRG/WP 10-20446
This paper presents a study on how climate conditions at numerous locations in Sweden affect the risk of onset of mould on wood sheltered outdoors. The results indicate that the risk is clearly higher in the south compared to the north of Sweden. These differences are mainly explained by colder and dryer winter periods in the north which is unfavorable for development of mould. The results also sh...
M Häglund, T Isaksson, S Thelandersson
Adsorption boundary curve influenced by step interval of relative humidity investigated by Dynamic Vapour Sorption equipment
2011 - IRG/WP 11-40547
The adsorption of water vapour from dry conditions by Norway spruce sapwood has been investigated using Dynamic Vapour Sorption (DVS) instrumentation. This equipment allows a fast and easy data acquisition as well as enables detailed studies of sorption properties using very small sample masses. In this study, particular focus was paid to the effect of step size on the sorption isotherms. Furtherm...
E Tang Engelund, M Klamer, T Mark Venås
Effects of microclimate, wood temperature and surface colour on fungal disfigurement on wooden claddings
2012 - IRG/WP 12-20490
Wooden claddings are common in façades in Norway, and Norway spruce (Picea abies) is the most frequently used species. The cladding is a major part of the facade, and it has visual requirements that may define the aesthetic service life. The visual changes that occur during weathering can be colour changes, abrasion or wear, blistering, flaking, and even cracks in the wood or coating, but more of...
L Ross Gobakken, G I Vestøl
Activities of moulds on wood as a function of relative humidity during desorption and absorption processes
2013 - IRG/WP 13-10794
Three different types of indoor moulds: Penicillium brevicompactum, primary colonizer; Alternaria tenuissima, secondary colonizer and Trichoderma harzianum, tertiary colonizer, grown on wood were measured for their activities under different relative humidity levels. The activities were measured by isothermal calorimetry. The activities of the moulds changed with the change of the relative humidit...
Yujing Li, L Wadsö
Mould growth on spruce claddings and the effect of selected influencing factors after 4 years of outdoor testing
2015 - IRG/WP 15-30671
Norway spruce (Picea abies) is the most frequently chosen wood species as claddings in façades in Norway, and is used both coated and uncoated. The visual changes that occur during weathering can be colour changes, abrasion or wear, blistering, flaking, and even cracks in the wood or coating, but more often growth of mould and blue stain fungi is the main challenge. A field test with synchronous monitoring of relative humidity, air temperature, material temperature and wood moisture content in Norway spruce claddings has been performed in southern Norway as part of the ClimateLife project. Visual evaluation of blue stain and mould growth according to EN 927-3 was performed, and evaluation data after 46 months exposure is presented. The objectives were to study the effect of 1) environment, 2) cardinal direction and 3) colour of the coated surface on growth of blue stain and mould fungi and to study the variation in relative humidity, air temperature, wood moisture content and material temperature. After 46 months exposure, the red coating system had generally the lowest mould ratings and the uncoated claddings had the highest. Of the white coloured claddings the ones facing south had lower mould ratings than those facing north, but the opposite were found for red coloured claddings. The relative humidity was higher in front of claddings exposed northwards and in a shaded environment compared to an open environment against south. In an open environment red coloured claddings had the lowest wood moisture content and highest material temperature, and red coloured claddings against south had the highest maximum material temperature.
L Ross Gobakken, G I Vestøl