The selection of instructions·General situation selection instructions1. Plastic drainage inspection well design, construction, inspection and maintenance in the new, expansion and renovation of urban and rural areas of municipal, residential area, public construction area of underground drainage pipeline project, the inspection well diameter is less than or equal to 1000 mm, the buried depth is less than or equal to 6 m.2. Can human operation check Ii (pipe wall) well diameter should be greater than or equal to 700mm.3. The water outlet of the road should be used in the inspection well s...