PVC pipe creates chlorine gas, which slowly destroys the UV light stabilizers in polyethylene greenhouse film.
This action will cause a some types of 4 year greenhouse plastic to have holes and tears after the first year.
For this reason, your greenhouse plastic warranty may be voided if your plastic comes in direct contact with PVC. Contact the greenhouse plastic manufacturer for details.
Greenhouse plastic can also be damaged by oil based paints, wood preservatives, chlorine based disinfectants, and certain pesticides, especially those containing sulfur or copper.
To extend the life of your greenhouse plastic,
Another technique is to cover the hubs and struts with a non-PVC tape.
This problem is not specific to our geodesic domes, but is evident in hoop houses or any type of PVC greenhouse structure.