In mass housing projects, multiple devices are collected on a common shaft or manifold; positive pressure and wet (P1–W) operation are often the norm. Cascade boiler rooms, LAS/LASS (air+smoke) systems, and renovation lining solutions are typical. Backflow prevention, leak-proof sleeves, drainage, and maintenance access are essential for safe operation. Fireproofing details, acoustic/draft calculations, and shaft layout are all considered together in the project.