FEATURES
Vascol Azure maintains the natural colour of wood .
that the chemical has penetrated deep enough for the wood to comply to the SANS 1288 and SANS 10005 national specifications . Although the treatability of wood is related to its porous structure , it is also influenced by other parameters such as wood moisture content , drying technique , preservative formulation , and the treatment process . For this reason , our technical support team is always on hand to assist our customers in achieving the correct degree of preservation and thereby ensure the end-use performance of Vacsol Azure in the consumer market ,” says du Plessis .
“ Penetration testing is most important at Lamtim Products . Without testing and the support of Lonza ’ s technical backup , we cannot maintain our SABS certification ,” comments Chapman .
The penetration test for Vacsol Azure differs from CCA and is carried out by placing samples into the charge at various points among the bundle , which can be either block stacked , or strip stacked . The wood must be below a 17 % moisture content and should be in its final shape and form with all machining and rip sawing completed . It must also be free of any signs of fungal decay and insect attack and should not be treated if it has been affected by sap stain , as this results in excessive absorption of the treating solution .
Denise Conradie , quality assurance and technical manager at Lonza says that once the double-vacuum process is completed , the samples must be removed , cut open halfway and sprayed with a PAN indicator . The preferred method of applying the indicator is by spraying to get an even wetting across the surface . It is inefficient to apply so much indicator that it runs off the surface as this will result in it smearing and the dis-colouration will not present the correct penetration levels . The colour of the PAN indicator is yellow and when applied will change to red to indicate the presence of Vacsol Azure .”
MONITORING TREATMENT PLANTS
A penetration test is required to determine the degree of preservation , which is expressed in two ways – namely retention and penetration . The penetration is determined by measuring the depth of the red discolouration from the wood surface . The retention is calculated from the weight of preservative per cubic metre and expressed in kg / m 3 . Importantly , the retention level will dictate the hazard class of the treated wood .
When Vacsol Azure has been correctly applied at the stipulated concentration , the retention level should meet the required retention as per SANS specification for both H2 and H3 hazard class applications . For the treatment of selected H3 exterior above-ground applications , an additional suitable water repellent and UV resistant coating is required .
In South Africa , all wood treatment plants are monitored through a compulsory third-party product certification scheme . Sawn treated wood must display the treater permit name , the stress grade marking , the hazard class the wood has been treated to and a product certification mark of one of the approved certification bodies – either the South African Bureau of Standards ( SABS ), the South African Technical Auditing Services ( SATAS ) or African Certification and Testing ( Pty ) Ltd ( ACT ). In addition to these legislative requirements , wood treated with a preservative supplied by Lonza Wood Protection must bear the TAN trademark .
Du Plessis concludes that “ through introducing Vacsol Azure to the South African market has proved to be yet another example of how listening to our customers ’ needs gives Lonza the opportunity to provide wood treatment products that add value to our customers ’ business and above all help to ensure that the wood preservation industry will grow well into the future .”
24 FEBRUARY / MARCH 2021 // www . timberiq . co . za