In process of buying new 1980's built house. Someone at some point, has run a gas pipe under solid floor to feed a flueless gas fire...which is now capped off (as it was condemned - failed co2 test) I want to get rid of old leg of live gas pipe under floor...plumber says that it's ok to leave..provided its been installed properly...thing is, how do we know if it's installed properly? He says he has no way of telling where pipe source comes from....without digging up floor? Am I stressing for nothing? :o I didn't think this would be an impossible job?