What is ETFE Material?
Widely used in Japan for decades but with little use in the United States, Ethelyne Tetrafluoroethelyne (ETFE) is a fluoropolymer that is increasingly being used as a cladding material in the construction of greenhouses due to its unique properties. At Ceres, we are excited to offer this new glazing material to clients looking to retrofit their current greenhouse and clients interested in a full scale Ceres energy efficient ETFE greenhouse. For those who are unfamiliar with ETFE film, let’s go over the benefits of using this material for your greenhouse project.
Why use ETFE greenhouse film?
ETFE film allows for more than 95% light transmission, including the UV spectrum. Even on low-light days, more light will be entering your greenhouse. Full spectrum light, especially UV-A, plays an important role in plant health and nutrition. Your plants will grow faster, healthier, and taste better. In a natural UV environment, plants produce a higher number of protective compounds, like beta carotene, anthocyanin, and glycosides, that contribute to the color, flavor, and nutrition of many plant species. UV spectrum light also acts as a gentle radiation, cutting down on molds, funguses, and certain plant diseases in your greenhouse.
After replacing their polycarbonate glazing with ETFE film, our friends at Golden Hoof greenhouse (pictured below) have experienced a decrease in pest pressure, specifically slugs and aphids, since installing their ETFE film. We believe that this may have something to do with an increase in UV spectrum light in the greenhouse because researchers have found that higher levels of glycosides and other protective compounds deter pests in some plant species.
Another benefit of increased light transmission is increased energy-efficiency because the high degree of transparency reduces the need for artificial lighting. This leads to energy savings and a lower carbon footprint.
ETFE is lightweight and strong. Only 1/100th the weight of glass, ETFE allows for wider truss spacing and, therefore, less shading in your greenhouse. Wider truss spacing also leads to cost savings in the design and construction of the greenhouse. And yet, ETFE is remarkably strong for how lightweight it is. ETFE can elongate up to 400% without breaking, making it a great option for locations that experience a lot of hail, high winds, or are prone to earthquakes. We have different thicknesses of ETFE we can offer (60 um – 300 um) based on site specific weather challenges.
ETFE ages well. A typical polyethylene greenhouse will need to be re-sheeted every 3-5 years due to steadily lower light transmission levels. Data shows that ETFE film will only lose 5% light transmission over 20 years. We have seen ETFE greenhouses in Japan continuing to perform well at over 30 years of age. ETFE is self-cleaning due to its nonstick surface, which means snow slides off faster than other glazing materials and it resists dust or pollen that contribute to lower light transmission levels. It is also resistant to UV radiation and chemical damage which contributes to its durability.
The photo above is a project done by Vector Foiltec, and it is an ETFE enclosure over a Mangrove Hall at the Royal Burgers Zoo in the Netherlands. The first structure (above) was built in 1982 and functioned sufficiently until it was replaced in 2017 (below). The construction of the newer enclosure over 30 years later speaks to the durability and strong positive attributes of the ETFE film.
ETFE can be installed in one, two, or three layer configurations. The outer layer is thick (100-300 microns) to protect the greenhouse from the elements and is completely clear to allow up to 95% light transmission. The inner layer is able to be much thinner (60 microns). Both layers combined create a diffuse effect which eliminates shadows and scatters the light as it enters the greenhouse, allowing the light to penetrate the plant canopy more effectively. A bubble of air sits between the two layers of ETFE, which gives it an R-value of about 1.8 ft2·°F·h/BTU (US) or 0.32 m2·K/W (SI). ETFE film is available in clear or diffuse.
ETFE is flexible and versatile
ETFE is a highly flexible glazing material that can be shaped and formed into complex shapes and geometries. This allows for greater design flexibility in the construction of greenhouses, which can lead to more efficient use of space and improved aesthetics.
Besides greenhouses, ETFE film has been used to cover many types of structures including sports stadiums, hospitals, shopping centers etc., and is used in many other types of architectural projects due to its aesthetic appeal.
As greenhouse designers, we are always on the hunt for new technology that will allow our clients to grow better, more efficiently, and more sustainably than before. Experimenting with new products is a huge part of what we do and we’re excited to be able to offer ETFE and ETFE greenhouses as innovative solutions to greenhouse growers that require full spectrum, long lasting, and highly durable glazing materials. If you are interested to learn more about ETFE for your greenhouse project, contact us today!
Watch our short introductory video to ETFE on our Youtube Channel!
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