Rigid Vent other than Simpson 0ura-Vent, 3 screws must be used to secure rigid pipe to adaptor. Vent Guard (Part #946-506/ The FPI AstroCapw and FPI Riser Vent terminal are certified for installations using FPI venting systems as well as Simpson Dura-Vent• Direct Vent. American Metal Products Ameri Vent Dir