When using PVC make sure it's drinking water grade pipe, it's normally white. Not all PVC is created the same and many will leach chemicals over time, drinking water pipe is not allowed to have harmful chemicals.
PVC is too hard for most chins to bother chewing, they try but give up. It also doesn't come of in chunks, so if chewed they only get tiny bits that pass through without issue. Obviously if you see your chins chewing a lot on the pipe though you will need to remove it. I have a Y shaped one in my guy's cage that has been in there for over 6 years, the most they have done is a few teeth scrap marks. Another thing I use as a hangout tube is an old metal coffee tin, and I've also see other people use metal duct pipe for tubes too.