Most home inspectors in the united states when citing regulations pertaining to dryer venting refer to the international residential code.
Dryer vent booster fan code.
Dryer vent systems shall be independent of all other systems and shall convey the moisture to the outdoors.
When your dryer duct extends past this limit it decreases airflow pressure at the termination point and over time lent will easily clog the vent and completely.
There are absolutely no dryer booster fans that are listed or approved by 3rd party electrical mechanical or building testing laboratories anywhere in the us or canada.
Federal building codes for dryer vents and ducts.
According to some dryer installation instructions and local building codes booster fans should be added in the dryer duct run when the length of duct exceeds 25 feet with no bends 20 feet with one bend or 15 feet with 2 bends.
The dryer exhaust duct power ventilator shall be installed in accordance with the manufacturer s instructions.
Booster fans for dryers vents are prohibited under all building mechanical and electrical codes everywhere in the us.
A 15 foot long vent with two 90 degree bends 25 feet according to fl building code 504 6.
They are usually found in homes or buildings where the dryer vent run is exceptionally long and the dryer itself is simply not going to be able to get the job done.
Where a clothes dryer booster fan is installed and not readily accessible from the room in which the dryer is located a permanent identifying label shall be placed adjacent to where the exhaust duct enters the wall.
The dryer vent system is too long international residential code limits the length of a dryer venting system to 35 feet not including the flexible transition hose behind your dryer.
Domestic dryer exhaust duct power ventilators shall conform to ul 705 for use in dryer exhaust duct systems.
Fantech tjernlund and s p all have dryer booster fans that do just what the name implies.
Each fan has a built in controller which senses that the dryer is on and allows the dryer booster fan to run.
The fans are typically mounted in line in the existing duct preferably 15 feet or more from the dryer more on that later.
Terminations shall be a minimum of three feet from property line and 12 above the ground and not exhibit any type of screen.
The label shall bear the words this dryer exhaust system is equipped with a remotely located booster fan 2.
A summary of the typical codes relating the dryer venting is as follows.
