Can it be used in a sewer vent pipe?

According to the manual, using it in a sewer pipe is NOT a recommended application for this fan. SUITABLE FOR: Bathrooms / Kitchen / Apartments / Pools / Stores / Bars / Restaurants / Manufacturing facilities etc. We recommend contacting Vents US directly at: 888-640-0925 to see if they have any options for that application. If you have any further questions, please call us and we will be happy to assist you.