I need to replace a failed electric valve in my drip irrigation manifold. The pipes leading to each valve are 3/4" PVC, but they in turn are enclosed in what looks like black ABS pipe, at least 1/2" wider than the PVC. These pipes are open at the top. What is the purpose of the black pipe? Protecting the PVC somehow? I need to cut some of the black pipe away in order to get to the PVC so I can replace the valves. Any ideas?
It appears the black pipe is there to protect against impact damage. Were it not there the PVC could shatter relatively easy since it degrades in sunlight.