i would be safe to say that it held a lot more than 600 psi on the line. to help others understand psi. here is a prime example in real every day plumbers terms. when testing a 4 story building. all the first floor waste lines are at the same approximate pressure. roughly 19# of static head pressure. of course with water it is impossible to get an even 5# he is all that is required. it is the 4'' p