TAB Update #2

Last week, one of our clients requested that we test 3 paddle fans in one of their warehouses. By paddle fans, we are talking about the type of fan that mount to the ceiling in mga bahay. In this particular case, the fans were used to prevent air stratification during cold ambient temperatures. The 5 foot diameter fans were installed 18 ft. above the finished floor. Velocity measurements were taken approximately 1 foot below the fan discharge. Five readings were taken and averaged at the 3, 6, 9 & 12 o'clock positions. The fan speed was 210 RPM. The area used for the air flow calculation was the 5 foot diameter of the fan. With the average measured velocity of 540 ft/min, the fans were moving approximately 10,000 CFM.
Next, a vertical velocity profile was taken at 1 foot increments starting at 17.5 ft. above the finished floor.

Location (ft. AFF) --------------Velocity (FPM)
--------17.5 -------------------------------538
--------15.5 -------------------------------537
--------13.5 -------------------------------522
--------11.5 -------------------------------450
--------9.5 --------------------------------439
--------7.5 --------------------------------416
--------5.5 --------------------------------353
--------3.5 --------------------------------272
--------1.5 --------------------------------156

Lastly, a temperature profile was taken halfway between two of the fans at one foot increment starting at 21 ft. above the finished floor. The measurements indicated that there was 1 deg F temperature difference from top to bottom. The outside temperature at the time of the testing was 12.8 deg F. Heat for the warehouse was provided by 12 ceiling mounted electric heaters.