17
THECOMMERCIAL GREENHOUSEGROWER • APRIL 2018
FILMS •
2 x 0.18mm (with air inflateddouble layer) to 0.35mm
with single layer thickness for all its greenhouses. The
light transmission ranges from 88% to 92%, depending
on the type of film. The films alsohaveUV stabilisers
and low thermicitymeans the heat is retained inside the
greenhouses-especially important sonot to allow too
much coolingdown at night. “We also use films that have
anti-condensation anddiffusedpropertieswhich helps
lower the leaf temperature just like it does under glass.
Our double layer film contributes significantly towards
energy saving also,” saysMr vander Heide. Up to 40%
energy costs canbe savedby usingdouble layer film
whichhas air between the layers.
“The advances in film technology
means that if you chose the right
structure and film then polythene
can be just as effective as glass”
VDH can also supply its filmswithF-Clean technology.
F-CLEAN™ETFE film has a lifespanof up to 20 years
and a higher rate of light andUV transmission thanglass,
polyethylene or polycarbonate, allowing the full spectrum
of solar light topass through into the growing area. This
results in earlier blooms andmore colourful petals, as
well as sweeter fruit and vegetables. F-CLEAN™ is also
treatedwith an anti-drip coating, preventing condensation
andpotential dripdamage to the crop. Due to the low
surface energy of the fluoropolymer filmdirt getswashed
away easily by rain and so it is practically self-cleaning.
Elsewhere, NPStructures has responded to themore
frequent extremeweather by developing a new coating
for all themetal used in its structures, which combines
zinc, aluminium andmagnesium. Thismeans the life of
the structure canbe extendedby 20 times compared to
uncoatedones.
According toNPStructures’ Commercial Director, Nigel
Carr, the company hasworkedhardover the last few
years to close the gapbetweenglasshouses andplastic
covered structured and that includes the amount of
automationpossible.
He goes on to say that there havebeen various
developments inpolytunnel films over recent years
includinggreen andblue films, UVblocking, flame
retardant films and filmswithmore thermicity.Mr Carr
says that it is important to carefully consider the amount
of polythene used to recover existingpolytunnels because
that far outweighs the volume usedon new structures.
“With regards to recovering existingpolytunnels, we are
finding that the thicker 720g (180mu) polythene covers
are still themost popular by a long, longway. We are
also finding that customerswhohavepreviously tried
thinner 600g (150mu) covers are revertingback to the
thicker 720g (180mu) films.Weprovideboth600g (150mu)
and 720g (180mu) films, and so have little economic
advantage over which film a grower chooses, but as a
manufacturer of highquality polytunnelswewouldprefer
to supply the thicker, stronger filmwith new structures as
our experience shows they last significantly longer.”
ChrystalThermon aRichel tunnel (XLHorticulture).
WHATEVERYOUGROW.WHEREVERYOUGROW.
New shading products
Onlineproduct advice
For all greenhouses
Discover our renewed
greenhouse shading
products at sudlac.com
WE’VEGOTYOUCOVERED
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