ADAS® Greenhouse: ETFE film as an alternative to glass and polycarbonates
The ETFE film used in ADAS® Greenhouse systems is an emerging alternative to more traditional materials such as glass, polycarbonate sheets and netting. Due to its light weight, high UV transmission and high transparency, the use of ETFE roofing is being explored for large-span structures such as stadiums, where abundant light is needed for the growth of grass.
Image: The Forsyth Barr Stadium, New Zealand
ETFE vs glass
Between ETFE and glass, the biggest difference in performance would be in terms of weight. A single layer of 125μm ETFE film, weighing 350 g/m2 is over 100 times lighter than glass (15 mm). This means that less structural support is required, resulting in a more cost-efficient structure as illustrated in the image above.
Studies conducted on ETFE film and glass used for architectural purposes show that ETFE film has better visible light and UV transmittance even when double-layers are used. The visible light and UV transmittance of ADAS® Greenhouse ETFE film, with a typical thickness of 100μm, can be as high as 95% and 90% respectively.
ETFE vs polycarbonates
Although polycarbonate sheets are also significantly lighter than glass, a big issue that occurs with this material is UV degradation, which results in increased haze and brittleness and decreased light transmission over time. Yellowing is also accelerated in humid environments, and is hence a common problem in tropical countries.
In contrast, ETFE film experiences little to no UV degradation, with transparency levels remaining high even up to 20 years later. For different crops, the UV and visible light transmission levels can be controlled with a range of different ETFE films and solutions.
Additional advantages of ETFE film include its non-stick, self-cleaning surface that can also be further improved with anti-condensation and anti-fungal treatments. As dirt and stains can be easily washed away by rain, very little maintenance is required. Furthermore, the fire safety of ETFE cladding is ensured through its self-extinguishing properties, and in case of damage, it can easily be repaired or replaced.
The excellent performance of ETFE film for greenhouse use means that ADAS® Greenhouse is a solution to greenhouse systems that will ensure optimum lighting conditions and a higher quality, more abundant harvest.
The effects of ultraviolet radiation on polycarbonate glazing, G.F. Tjandraatmadja and L.S. Burn Csiro
Experimental Assessment and Thermal Characterisation of Lightweight Co-Polymer Building Envelope Materials, Eleni Anastasia Dimitriadou