PVC and UV Degradation
The Sun's ultraviolet light, or "UV" rays only affects the top 1/100th of an inch (.01") of a PVC pipe.
This scientific fact is supported by the following articles:
At most, the Sun's UV rays will discolor the surface of the PVC pipe. UV rays will not affect the structural integrity of our domes.
Also, our patented hub design does not rely on plumbing joints or bent pipe to work. When we hear that "UV will degrade a PVC structure", the reality is that the long-term design of a PVC structure is flawed, not that the PVC structure fails from UV rays.
Plumbing joints, plumbing elbows, plumbing tees, etc. are meant for plumbing, and not for building PVC structures. As the structure is moved or stressed by wind load, these plumbing joints crack, or the plumbing glue fails, as they are not designed for this purpose.
Hoop houses have a similar problem, in that the PVC pipe is bent into a 180 degree angle to make the hoop. This puts the PVC pipe in a highly stressed condition, with no release of tension, until extreme cold temperature can invite cracking. No house is ever plumbed with PVC pipe bent in a 180 degree angle, because the PVC plumbing will crack and fail, just like a PVC hoop house can crack and fail. The failure of a PVC Pipe Hoop House is not due to UV degradation, but in using PVC pipe in an impractical design.
If you look at the way our hubs and struts are constructed, we do not use plumbing joints, or glue, or bend PVC in 180 degree angles. Our domes are built with a patented hub design that holds the PVC pipe so that they are naturally straight and unstressed. Only when the pressure is applied to the dome is PVC stressed, with the geodesic shape distributing the stress to all components. When the pressure is released, the PVC will flex back into a natural unstressed state.
Our patented hub design is meant for permanent construction - specifically intended for building a geodesic dome - and is superior to plumbing joints and other construction methods.
