Reasons for not using perforated impingement plate - API 660

API-660, clause states that ‘perforated impingement plate baffles shall not be used’. Can anyone throw some light on the logic behind this prohibition? Any input would be appreciated.


The perforations slow the velocities coming off the plate. It is not desirable to slow this velocity going toward the tubesheet. Slowing this velocity can create a “stagnant area” where there can be corrosion and fouling.

The “stagnant area” is the area from the forward front of the impingement plate and the tubesheet. I call it an “area” but it is actually more of a “volume”…

Above is a snippet.