BS EN 12056 is the UK and European Standard for the design of gravity drainage systems inside buildings, covering soil and waste pipework, ventilation, roof drainage and maintenance access. The standard is widely used in flats, mansion blocks and commercial premises across central London where internal stack design requires careful sizing for multiple discharge units. It is regularly referenced in Building Regulations Part H Approved Documents and in specifier guides for cast iron, PVC-U and HDPE systems. Practical implications for contractors include the need to size soil and vent pipes to the connected discharge unit load, provide trap seals of the correct depth and ensure adequate ventilation through stack vents or air admittance valves. The standard is published in five parts, with BS EN 12056-2:2000 covering sanitary pipework layout and calculation widely used by domestic designers.
BS EN 12056 (gravity drainage inside)
European Standard for the design of gravity drainage systems inside buildings.
