You shouldn't have to worry about Ptychosperma roots damaging your PVC line. Most tropical palms have less dense, rugged roots and don't "dig" to find moisture as there are ample amounts in habitat.

Thanks for the answer. I guess I tend to worry too much about the small details in my garden. I just hate to be like some people who dont plan right and end up having a nightmare years down the road. Like planting a ficus tree right next to their septic tank! I know palms can get large root balls and that made me nervous.