Wageningen University & Research study confirms that: ReduClean safely cleans AR-coated glass
Anti-reflective (AR) glass allows more light into a greenhouse and can save energy. Because of its premium price, it's vital to keep these qualities intact over time. This means that cleaning methods and agents must meet certain requirements. Researchers at Wageningen University & Research investigated this aspect. They concluded that ReduClean is one of the safest cleaning agents. ‘This confirms our experience and justifies its frequent use on AR glass,’ says Jelle Hoogland of Lumiforte.
The research project 'Cleaning AR Glass Safely and Effectively' (Report WPR-1171) was led by Dr. Silke Hemming and primarily focused on the long term. How safe are the common cleaning methods and resources when applied to AR glass on an annual basis or more often? Furthermore, do they clean the glass or leave dirt residues every time? Clear answers to these questions can promote a wider application of AR glass, with the associated, responsible cleaning routines.
The research has been done thoroughly. A team led by Dr.Silke Hemming selected four types of AR glass (plus reference glass without AR) and designed test setups to realistically simulate contamination and cleaning methods (high-pressure cleaning on the inside and mechanical brushing on the outside). The treatments were repeated ten times to simulate the effects over the usual 10-year amortization period.
Safely cleaning glass
In the research study, ten cleaning agents were tested (plus distilled water as a reference) on different types of AR glass from four suppliers, plus reference glass without AR. To establish whether a cleaning agent or method is safe, the difference in hemispheric light transmission before and after the cleaning was measured in the form of light loss. When light loss values for all glass surfaces fall between a +/-0.5% measuring tolerance, the cleaning agent combined with the cleaning method is considered safe.
Only three cleaning agents, including ReduClean, were found to be completely safe for AR coatings, brushing as well as high-pressure cleaning. The other cleaning agents resulted in a reduction in hemispheric light transmission for one or more glass types, which demonstrates that the AR coating had lost part of its effectiveness. In most cases, the reduction was greater for brushing than for high-pressure cleaning.
GS-4, which, like the double concentrated GS-4 Xtra is made by Lumiforte, cleans very well, but drastically affects AR coatings. ‘These fluoric products have been developed to remove stubborn dirt from glass surfaces,’ consultant Jelle Hoogland explains. ‘We never recommend these products for use on AR-coated glass. ReduClean works in a very different way. It was specially developed to remove ReduSystems coatings and to keep the AR layer intact. It is perfectly suited to remove temporary coatings such as ReduSol, ReduHeat, and ReduFlex Blue, but not a robust AR coating. It does exactly what it was intended to do.’
Effective, responsible cleaning
This successful study evaluated six cleaning agents for their effectiveness in removing chemical and microbiological contamination from AR-coated glass. ReduClean was not included in this study. ‘This is unfortunate because we believe that our product would also have been ranked highly in this study,’ says Hoogland. ‘This aspect was specifically considered in the product's development and experience with this product is unreservedly positive. There are quite a few growers who consider this the standard cleaning product for their greenhouses.’
Aside from this missed opportunity, Hoogland is pleased with the findings of the Wageningen University & Research study, which confirms his experience and the feedback received from actual practice. Furthermore, he agrees with Hemming's recommendation to always first test the effect of a cleaning agent on a small corner of sample of coated glass. ‘The availability of cleaning agents and types of AR glass is much broader than could be included in the study,’ he observes. ‘AR glass is expensive, so make sure you're safe. ReduClean will be an excellent choice in the vast majority of cases.’
When should I remove the coating?
Light levels fall a little further every day in August. The decision as to when to remove a coating is partly rational and partly depends on the weather and your green fingers.
At the forefront of horticultural innovations
Mardenkro maintains close contact with scientific researchers and is a member of the Club 100: a group of prominent horticultural suppliers that helps finance and steer research at Wageningen Greenhouse Horticulture. This way Mardenkro is at the forefront of horticultural innovations.