【Daily Question】Utilities - Water Supply and Drainage - 20200221

Thread Content

Which of the following statements regarding the installation of vent pipes does not conform to the current \"Code for Design of Building Water Supply and Drainage\"? (   )   A. A vent pipe that extends to the top should be installed at the top of the vertical pipes for domestic wastewater drainage. B. When it is not possible for the vent pipe to extend directly outside the roof, a combined vent pipe can be used. C. When it is inconvenient to install a vent pipe inside the building, a suction valve can be used as a substitute. D. The vent pipe must be connected to the air ducts and smoke ducts. Answer: C. Options A and B comply with Articles 4.6.1 and 4.6.6 of the current “Code for Design of Building Water Supply and Drainage Systems”, respectively. Option D complies with the provisions of Article 4.6.7 of the current Code for Design of Building Water Supply and Drainage. The vent pipe is connected to the air duct, and the dirty gases in the vent pipe may contaminate the indoor environment through the air duct ； Connecting the vent pipe to the flue will allow hot smoke to enter the vent pipe, damaging it.   Option C does not comply with the provisions of Article 4.6.8 of the current Code for Design of Building Water Supply and Drainage. A suction valve can only balance negative pressure; it cannot eliminate positive pressure, nor can it release harmful gases from the pipeline into the outdoor atmosphere. Therefore, a suction valve cannot perform the function of a vent pipe. At the same time, since the sealing materials of the intake valve are made of soft plastics and rubber, their failure due to aging goes unnoticed, which can allow harmful gases from the drainage pipes to enter the interior, posing a threat to human safety. Therefore, suction valves must not be installed in buildings to replace air ducts.