A stack pipe is a vertical drainage pipe that gathers wastewater from branches on more than one floor and conveys it to the underground drain. Stacks are common in flats, mansion blocks and multi-storey commercial buildings across London. They may be dedicated to soil flows, waste flows or both, depending on system design. Internal stacks are usually housed within service ducts to control noise and provide future access through removable panels. UK Building Regulations Part H requires stacks to be ventilated, of adequate diameter for the connected discharge units and fitted with rodding access at the base. Cast iron with bolted joints was the historical standard, but modern installations favour push-fit PVC-U or HDPE with acoustic insulation to reduce noise transfer between flats.
Stack pipe
Vertical drainage pipe collecting flows from multiple floors and discharging into the drain.
