The answer is: It varies. The pressure can be the inlet steam pressure all the way down to vacuum (if no vacuum breaker is installed)depending on the temperature of the secondary fluid and the flow rate. Just to add to TBP's answer...
If you are calculating the size of the steam control valve...
SarahGT
The issue here isn't merely condensate discharging through the orifice. Steam traps don't fail as an open orifice, they also have valve heads and disks that can get in the way periodically. The formula you show is the generally accepted one when the trap is discharging to atmosphere...
Maybe. It is usual practice to provide a dedicated vent for a Relief Valve. You may even tie several together to a common (larger) vent. The sizing is tricky and there isn't much guidance for it. The length of the line needs to be taken into account and the number of turns.
It may be...
