Single riser drainage pipe network system: one of the pipe network fittings of sewage drainage system in building area, which is a new technology and is replacing the original double riser drainage pipe network system. It is realized by a pipe, and the vertical pipe and the horizontal branch pipe are connected by ordinary pipe fittings, which is suitable for buildings within 9 floors. Double-riser drainage pipe network system: it is realized by two pipes, one for drainage and one for exhaust, which is suitable for buildings with floors above 10. Three-riser drainage pipe network system: it is realized by three pipes, two drainage risers and one exhaust riser.