In an earlier video (found here:    • Replace backflow preventer - the smar...  ) I showed how to improve your sprinkler system setup with the use of PVC unions. In the comments it was suggested that these wouldn't hold up during winterization, which is the process of flushing out sprinkler lines with compressed air. I decided to test this by building a small scale PVC device and adding compressed air up to the normal winterization specifications of 40-80psi. When the system held at that pressure, I maxed out my air compressor to see what would happen!