difficulties to combine biological degradation factors with artificial weathering
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Difficulties to combine biological degradation factors with artificial
weatheringFocussing on how to measure and
evaluate
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
IntroductionIntroduction
Standardised methods:
• European: EN 927
• International: ISO
Problems: critical values
performance assessment
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
IntroductionIntroduction
Natural weathering, CEN/TC139/WG2:• accelerated natural exposure• Climatic Index
+ mimicry - transfer of biological
degradation patterns
Artificial ageing:• UVS equipment (UV-CON, QUV with spray option)• Wheater-O-meter (WOM)
+ fast - physico-mechanical
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
IntroductionIntroduction
Solution:
combined or sequential testing of physico-mechanical and biological ageing
• short-term• critical levels• special focus on biological performance
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Weathering and assessmentWeathering and assessment
Natural weathering:
- mimicrydisadvantages:• weather• sample variability
- harmonisation of specimens and expositiondisadvantages:
• macro- and microclimate
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Weathering and assessmentWeathering and assessment
Artificial weathering:
• higher reproducibility• more confidence in:
machines ageing cycles
• less time consuming• better control
dark & dry
cold period
water spray
UV light
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Weathering and assessmentWeathering and assessment
Assessment parameters:
• chalking• flaking• blistering• cracking• adhesion
Not necessary critical for all coatings
degradation phenomena on wood ‘missing’:
• biological• erosion• additional
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Weathering and assessmentWeathering and assessment
Needs for methodology:
• optimisation• prioriy of parameters• substrate:
hardwood softwood porosity, vessel grouping dimensional stability extractives
• sample size: boards window frame corners
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Biological factorsBiological factors
Biological factors can be essential part of paint degradation:
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Biological factorsBiological factors
Biological factors can be essential part of paint degradation:
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Biological factorsBiological factors
Standard tests: prEN927 3-5, EN152
artificial weathering
Alternative tests: • susceptibility• fungal growth on, through, in the coating and the substrate• impact analysis
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Biological factorsBiological factors
Additional parameters:
• film thickness• water and water vapour permeability• porosity• surface roughness
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Blue stain testingBlue stain testing
Blue stain testing basics EN152: + WOM
• coating not on the vermiculite medium (contact with uncoated side)• Aureobasidium pullullans and Sclerophoma pithyophila• evaluation of surface blue staining and zone free of blue stain
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Blue stain testingBlue stain testing
Reversed method:
• coating on the vermiculite medium, other sides sealed• Aureobasidium pullullans and Sclerophoma pithyophila• evaluation of surface blue staining and interior presence of blue stain
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
Blue stain testingBlue stain testing
Internal presence of blue stain in service:not just a blue free zone
Difficulties to combine biological degradation factors with artificial weathering - focussing on how to measure and evaluate
COST E18 SymposiumCopenhagen 16-02-2004
ConclusionsBlue stain testingBiological factorsWeathering and assessmentIntro
Joris Van Acker – Imke De Windt – Jan Van den Bulcke
ConclusionsConclusions
- Modern coatings: low VOC + low biocidal content- Increased impact of biological factors- Yearly changes in impact of biological coating degradation- Reproducible testing: artificial ageing + laboratory test method- Artificial ageing should be specific for wood - Wood coatings mainly fail due to moisture impact (swelling / shrinkage)- Blue stain in service testing of coatings differs testing fungicidal impact- Modern water- borne wood coatings should be able to
resist biological factors...by means non-biocidal components or parameters...
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