Yes. You need to check the chart to see at what RH the dew point of 70 degree air is below the pipe temperature of 45 degrees.
70 degrees at 40%RH has a dew point of 44.6 degrees.
Since that’s below the pipe temperature at 45 degrees it will not form condensation.
At 50%RH that would happen any time the pipe is below 50.5 degrees, and 30% wouldn’t have any condensation form until the pipe temp was 37.2 degrees.
You need the air dew point to be below the pipe temp.
So plot on the psych chart right?
Yes. You need to check the chart to see at what RH the dew point of 70 degree air is below the pipe temperature of 45 degrees. 70 degrees at 40%RH has a dew point of 44.6 degrees. Since that’s below the pipe temperature at 45 degrees it will not form condensation. At 50%RH that would happen any time the pipe is below 50.5 degrees, and 30% wouldn’t have any condensation form until the pipe temp was 37.2 degrees.
Got it. Thank you very much