Hi all. I'm new here and have a question. I'm remodeling a duplex. The 3 inch soil stack is straight vertical. It's a two storey. There's a total of 10 dfu on it. From the top down, second floor, lav, then WC. Ground floor lav, kitchen sink on shared trap arm. And last is washer standpipe. All the drain arms are properly sized. The longest trap arm is the upper lav at about 24 inches. Everything else is closer. At thus point there's no issues. Would some type of dry vent be needed from the lower floor, to up past the highest fixture? Or is the 3 inch stack sufficient. I'm re doing drywall and it's exposed. Thanks.