I can't really tell you what the rules are,

usually, we do 1.5X max working pressure for 5-10-20 minutes and the surveyor is happy, he says "Nothing exploded, very good" and then we can continue to vacuum the system.

What is the point of keeping the pressure for 24 hours? if it wasn't leaking in 5 minutes, it's not going to leak after 10 hours.

And then there is the other surveyor who wants 1.5X pressure for 24 hours.
I will put the pressure up, with an external manometer for the surveyor to monitor.
Then I will give him my small note book and say "if you want the pressure to hold for 24 hours, here is a note book, please note any decrease in the pressure every 30 minutes, I am going home now"