Research methods: Based on taking the drainage system with single horizontal branch pipe to drain water, the top of vertical pipe to lead air and the bottom of the pipe going to inspection shaft through horizontal drainage pipe as lab research model, the analysis was made for the pressure change caused by movements of water flow and airflow within building.
Research results: The complicated movements of water flow and airflow in drainage system for building could make change of pressure in the system and the change of pressure was the key factor for causing air inner spilling in drainage system.
Research conclusions: The movements of water flow and airflow in drainage system for building could make change of pressure in the system and change of pressure was the basic cause for damage of water block and harmful gas going into room. It was an effective way for solving the problem of air inner spilling in drainage system for residential building to equip drainage system with special vertical drainage pipe, rationally lay out drainage pipe, use high quality sanitary appliance and piping materials, ensure the construction quality and rationally use drainage system.
2006, Vol. 23 
