What would the average life of pvc piping would be if it carries high free chlorine gas mixed with water?
Piping is 3" diameter and the chlorine is as high as 4 ppm free. The temperature can be as low as 3C for prolonged
periods.
4ppm in temperature below 20-25 is very safe.
Lifetime will depend from PVC quality (uniformity of polymer), but so low concentration shall not affect in general.