Quality Assurance

Two-Way Air Vents: Proven Effective

By: Evan Kennard, Product Testing/Code Specialist

Perhaps one of the most recognizable elements of a Duro-Last® Roofing System is the Two-Way Air Vent. Designed for use on mechanically fastened applications, they help eliminate negative air pressure and promote airflow throughout the roofing system. While the effectiveness of the Two-Way Air Vent has been objectively proven through decades of real-world applications and analysis, we now have scientific data to support this evidence. 

The Engineering Services team recently performed tests on our Two-Way Air Vents in a Florida lab, finding that they released 42% of the pressure from mechanically fastened Duro-Last Roofing Systems. The results of our testing actually prompted a specification change to the installation location of two-way air vents, requiring placement in the high-pressure zones of the roof (Zone 2 & Zone 3). See the new vent layout sample drawings below, highlighting examples of vent placement for different size roofs. Additionally, be sure to review the Duro-Last Technical Bulletin #19-04, which outlines the revisions to Two-Way Air Vent requirements. And as always, don’t hesitate to contact the Engineering Services team at 800-248-0280 if you have any questions.