Citation
Bean, J. (1998), "Advances in exterior wood coatings", Pigment & Resin Technology, Vol. 27 No. 6. https://doi.org/10.1108/prt.1998.12927faa.002
Publisher
:Emerald Group Publishing Limited
Copyright © 1998, MCB UP Limited
Advances in exterior wood coatings
Advances in exterior wood coatings
The PRA hopes that the Shielding Conference will be as successful as the conference also held in Brussels 19-21 October last on "Advances in Exterior Wood Coatings and CEN Standardisation". There were 29 papers given by experts from all over Europe, plus one from Japan. It generated much interest as it was of value to raw material suppliers and coatings manufacturers, as well as to specifiers, applicators and users of wood coatings. Importantly, it also provided a unique opportunity to discuss the shape and direction of standards development in this field. An example of this was the paper by Dr Roy Miller of the UK's Building Research Establishment giving an overview of the development of EN 927 Paints and Varnishes coating materials for exterior wood. The standard aims to improve communication between manufacturers and users, to define test methods for key coating properties, and facilitate specification of exterior wood coatings. Part 1 (classification and selection) was published in 1996; the other four parts are in the final stages of the CEN approval procedure.
Following the first session of five papers on standards and evaluation, there were six papers on moisture transport, six on weathering and biodeterioration, six papers on substrate and characterisation, and six on formulation and development.
With regard to moisture transport through wood coatings, Jon Graystone of the PRA pointed out that for many years there has been debate about the optimal permeability characteristics for the many types of wood coating now available. Some coatings stand accused of "trapping" moisture, others make claims of allowing "breathing" but may not control movement. The question therefore stands, "is there an optimal band for moisture transport for a given set of conditions?". His paper reviewed the evidence of past and more recent work and set out to consider whether the issue can yet be resolved. A new performance standard for wood coatings (prEN927-2) is now nearing completion. It is thus vital that the question be answered to enable realistic performance criteria to be included in the specification. This would be of great eco-nomic and practical benefit for the European consumer.