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Experimental study on air pressure variation in a horizontal pipe of single-stack drainage system
Tingchao Yu1, Qiang Ding2, Luwen Wang1
1Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China
Summary
This study investigated air pressure variations in single-stack drainage horizontal pipes. Higher water flow rates increased pressure fluctuations, while sealed vents and submerged outlets caused significant pressure changes, impacting trap seal integrity.
Area of Science:
- Building Services Engineering
- Fluid Dynamics
- Plumbing Systems
Background:
- The water trap seal in sanitary appliances is crucial for preventing foul gas ingress.
- Limited research exists on air pressure variations within horizontal pipes of single-stack drainage systems.
Purpose of the Study:
- To investigate air pressure variations in horizontal pipes of single-stack drainage systems.
- To identify key parameters influencing pressure fluctuations.
Main Methods:
- A physical model study was conducted.
- Investigated the effects of water flow rate (Q_w), inlet height, ventilation condition, and outlet condition on pressure variation.
Main Results:
- Pressure fluctuations increased with Q_w but decreased along the horizontal pipe.
- Sealed ventilation led to choking flow and decreased horizontal pipe pressure.
- Fully submerged outlets significantly increased horizontal pipe pressure.
Conclusions:
- Water flow rate and outlet conditions are critical factors affecting pressure variations in horizontal drainage pipes.
- Sealed vents and submerged outlets can compromise trap seal integrity and should be avoided in system design.
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