As long as the humidity is good, you can wait for 24 hours. Give the little one some time, it may be absorbing the yolk sac.
Chicks are actually still growing ad coming to the end of their "gestation period" even when they have piped.
As long as you can see the beak and the inner membrane is broken for the chick to breath your OK.
The problem becomes when the membrane starts to dry on the chick and they can not move to "zip" the egg.
This is the time it takes a bit of experience to known when to help the chick out.
If you do decide to help, be sure to take ONLY the part of the shell that had the air sac. Wait another 12 hours and if you see the chick is having a time of it carefully start to break the shell down and if you see blood STOP !
Here is a pic for you that may help:
We get to the point and stop and wait. Just make sure you have good humidity and temperature
These two are running the property and perfectly healthy. They were BIG cochins.
It should be noted that if you are using the "egg carton" method for hatching to take the chicks out of the carton and lay them down as shown in the pic.