Franz Heymann wrote or quoted:
"Tim Tyler" wrote in message
Franz Heymann wrote or quoted:

What Alan wrote seems to have been:

``Polytunnel covers need to be of ultraviolet inhibiting [UVI/EVA]
polythene of which three grades are offered. We chose Politherm
Plus in 720g with anti fogging and high light transmission properties.''

I can't see any problem with that.

I can. Quite clearly. UVI/EVA polythenes are not used because they
inhibit ultrtaviolet light. All polythenes "inhibit UV light" in the
sense that they absorb it. The UVI/EVA materials have the property
that they are somewhat more resistant to deterioration by UV radiation
than other polythenes.

The thing is, the "UVI" in "UVI/EVA" *stands for* "ultraviolet inhibited".

It is polythene that has been dosed with a chemical inhibitor that
prevents breakdown when exposed to UV light - e.g.:

``Ultraviolet-inhibited polyethylene lasts longer than regular
polyethylene. It has an inhibitor that prevents the rapid
breakdown caused by ultraviolet light.''

- http://www.envirocept.com/gh_guide/greenhouse_kits.htm

Alan's sentence simply spelled out what "UVI" actually means.
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