Does it really matter how the exhaust duct is installed? YES! It is critical when installing the exhaust duct that special care is taken to use the proper duct material, correct size and length while minimizing the amount of elbows used.
Improper ducting can damage electrodes, clog cooling passages and deteriorate the duct material itself due to excess ozone. Without proper air flow the expected life of the ceramic electrode decreases and can also cause ozone to be present in the work space, affecting the health and well being of personnel.
Exhaust duct connections Do’s and Don’ts
- Use as large a duct diameter as possible (but never smaller then the recommended diameter).
- Use PVC, stainless steel or aluminum.
- Minimize the number of elbows and transitions.
- Keep the duct runs as short as possible.
- Seal all duct joints to reduce pressure loss.
- Check to make sure the blower fan is rotating in the correct direction (as indicated on the blower housing).
- Ensure proper electrical connections, as improper connections can cause the fan to rotate in the wrong direction, greatly decreasing performance.
- Do not use galvanized duct. It will quickly corrode and need to be replaced.
- Do not use flexible duct. It will greatly increase static pressure loss. If flexible duct must be used, select a diameter at least 1.3 times than recommended for smooth duct and keep the length to a minimum.
- Do not have any elbows within three (3) duct diameters of the inlet or exit to the blower. They can create turbulence that will affect blower performance.
Originally appeared in eMaintenance: Surface Treating 4th Quarter 2006.