GUANYu-xi,YANXin,FANGZheng,et al.Constant Flow Rate Test for Drainage Capacity of Non-extended Top Ventilation Double Stack Drainage System[J].China Water & Wastewater,2025,41(21):149-154.
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Constant Flow Rate Test for Drainage Capacity of Non-extended Top Ventilation Double Stack Drainage System

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第41卷 Number: 第21期 Page: 149-154 Column: Date of publication: 2025-11-01
Author(s):
GUAN　Yu-xi1; 2;  YAN　Xin2; 3;  FANG　Zheng2;  REN　Shao-long4
（1. Shenzhen Water and Environment Group Co. Ltd.， Shenzhen 518031， China； 2. School of Civil Engineering， Wuhan University， Wuhan 430072， China； 3. School of Environmental and Municipal Engineering， North China University of Water Resources and Electric Power， Zhengzhou 450000， China； 4. National Building Drainage System Technology Center Laboratory， Shanxi Xuanshi Industrial Group Co. Ltd.， Jincheng 048400， China）
Keywords:
non-extended ventilation double stack drainage system;  loop ventilation;  combined ventilation;  pressure limit;  water seal loss
Abstract:
In high-rise and super high-rise buildings, the drainage system may not extend through the top for ventilation purpose due to architectural aesthetic considerations or other performance requirements. A comparative experiment was conducted to evaluate the drainage capacity of three non-extended top ventilation drainage systems relative to the traditional extended ventilation drainage system, using a 60-meter-high tower in Shanxi Province as the test site. The reduction in hydraulic performance of the traditional extended top ventilation drainage system caused by the non-extended top ventilation form was assessed using the constant flow rate method. The impact of non-extended top ventilation form on the drainage capacity of various drainage systems varied significantly. The combined ventilation drainage system was the most adversely affected, experiencing an 81.25% reduction in drainage capacity. In contrast, the loop ventilation drainage system equipped with a secondary vent stack demonstrated greater resilience to non-extended top ventilation form, maintaining a post-modification flow rate of 7.0 L/s. The non-extended top ventilation form induced significant negative pressure in the upper floors of the drainage system, potentially compromising the integrity of water seal loss in sanitary appliances within upper floors. However, given the relatively low drainage flow rate, the associated water seal loss remained minimal.
Last Update: 2025-11-01