Aeration and gutter water levels in siphonic roof drainage systems

An investigation is presented into how negative system pressures, the degree of aeration, and gutter water levels are affected by the number of outlets in a siphonic roof drainage system. The experimental results show that system pressures decrease if outlets are blocked. It is also shown that the depth of water above an outlet is strongly influenced by the negative pressure acting at the outlet. As the suction effect at the outlet increases, due to lower system pressures, more water and air will be drawn into the outlets and this will result in a corresponding increase in overall gutter water depth. The results also show that there is often built-in redundancy in multiple outlet siphonic systems experiencing lower-intensity rainfall events, and if one or two outlets were blocked, the system would still operate satisfactorily. A new outlet suppressor was trialled and this was shown to reduce gutter water levels by up to 58% at some positions in the gutter.

Il est présenté une enquête sur la manière dont les pressions négatives dans le système concerné, le degré d'aération et les niveaux d'eau dans les chéneaux sont affectés par le nombre d'orifices de sortie dans un système d'écoulement des eaux de toit par siphonnage. Les résultats expérimentaux montrent que les pressions dans le système diminuent si des orifices de sortie sont obturés. Il est également montré que la profondeur de l'eau au-dessus d'un orifice de sortie est fortement influencée par la pression négative s'exerçant à l'orifice de sortie. Plus l'effet de succion à l'orifice de sortie augmente, en raison des pressions plus faibles dans le système, et plus les quantités d'air et d'eau entraînées dans les orifices de sortie seront importantes, et cela aura pour résultat une augmentation correspondante de la profondeur générale de l'eau dans les chéneaux. Les résultats montrent également qu'il existe souvent une redondance intégrée dans les systèmes à siphons comportant des orifices de sortie multiples et soumis à des épisodes pluvieux de faible intensité, et que si un ou deux orifices de sortie sont obturés, le système fonctionne encore de manière satisfaisante. Un nouvel obturateur d'orifice de sortie a été essayé, ce qui a permis de montrer que celui-ci réduit dans une proportion allant jusqu'à 58 % en certains points les niveaux d'eau dans les chéneaux.

Mots clés: aération, niveaux d'eau dans les chéneaux, pressions négatives, écoulement des eaux de toit par siphonnage     

Numerical simulation of the dynamic operation of multi-outlet siphonic roof drainage systems

Although siphonic roof drainage systems have been installed in Europe since the 1970s, the design of such infrastructure is still based on steady state theory. Such approaches are only truly applicable at the design condition, under specific rainfall conditions, and cannot be used to assess the response of siphonic systems to alternative rainfall conditions and/or operational scenarios. Previous research at Heriot-Watt University led to the development of a numerical model capable of accurately simulating the performance of single outlet systems under a range of different conditions. The work reported herein details the logical extension to this work; i.e., the development of a numerical model to simulate the performance of multi-outlet siphonic roof drainage systems. The experimental work undertaken to assist in the development of the new model boundary conditions is briefly described, and relevant results are illustrated. The development of the numerical model is then detailed, and model output is presented. Finally, conclusions are drawn regarding the developed model, and plans for future work are outlined.     

虹吸式屋面雨水排水系统的应用

介绍了虹吸式屋面雨水排水系统的产生及适用范围,比较了传统的屋面雨水排水系统和虹吸式屋面雨水排水系统,研究了虹吸式排水的三个阶段,得出了虹吸式排水系统更经济的结论,以推广虹吸式屋面雨水排水系统。     

屋面虹吸雨水排水系统设计与施工

介绍了虹吸式屋面雨水排水系统的设计及施工要点,包括设计的基本规定、雨水斗流量计算办法、屋面天沟技术要求、屋面溢流系统技术要求、雨水斗的安装工艺、管道及悬吊系统的安装工艺、系统的施工验收要求等。     

屋面虹吸式雨水排水系统

为了满足大型单体建筑物屋面雨水能够及时、迅速排放,目前国际上采用虹吸式雨水排放技术,就屋面虹吸式雨水排放系统的工作情况、系统组成等方面进行了介绍,经济效益分析结果表明,虹吸式雨水排水系统具有较强的先进性、合理性。     

沈阳恒隆广场虹吸式屋面雨水排水系统深化设计

本文介绍了虹吸式屋面雨水排水系统深化设计流程、要点,虹吸效应形成的工作流程以及系统施工工艺流程,指出在不同结构屋面施工时的注意事项,并对公共建筑此类项目的设计进行了总结、提出了建议。     

Air water flows in building drainage systems

This paper investigates the mechanisms of two-phase flows that occur in commercial and industrial roof drainage systems. Both traditional gravity-fed and siphonic roof drainage systems are examined.

Air entrainment plays a fundamental role in the performance of siphonic roof drainage systems. In particular, air entrainment has a significant effect on:

• maximum system flowrate capacity;

• pipe friction losses;

• operational system pressures;

• operational gutter water depths; and

• ability of the system to prime.

However, experimental results presented here demonstrate that the reduction in system capacity is not directly proportional to the increase in air content. One possible explanation for this is that water and air will be affected differently by sub-atmospheric pressures. The effect air entrainment has on roof drainage performance is investigated. The ways in which air is introduced into the system are identified and the effects of different air/water ratios are quantified. Finally methods for reducing air entrainment are described.     

虹吸式屋面雨水排水系统应用

系统阐述了虹吸武屋面雨水排水系统的工作原理、系统组成、应用范围，通过具体工程实例，介绍了虹吸式屋面排水系统的施工工艺，以推广虹吸式屋面雨水排水系统的应用。     

虹吸式屋面雨水排放系统施工技术

本文通过福建师范大学综合体育馆的工程实践,主要介绍虹吸式屋面雨水排放系统的施工技术     

建筑排水立管排水能力概念辩析

2009年版的《建筑给水排水设计规范》引入"最大设计排水能力"的概念,与近年来进行排水能力测试的"最大排水能力"构成了立管排水能力的两个重要概念,同时衍生出了很多相关的概念。为了便于设计人员了解各种概念的定义,抓住概念本质上区别,更好地指导工程设计,本文就建筑排水立管排水能力的若干概念进行辨析。     

浅谈HDPE管屋面虹吸排水系统施工技术要求

从HDPE管材切割、管材的热熔准则、热熔步骤及安装步骤介绍HDPE管屋面虹吸排水施工技术要求，以完善HDPE管屋面虹吸排水施工工艺，推广HDPE管屋面虹吸排水在工程中的应用。     

不同排水材料对轻型种植屋面土壤热湿环境的影响

构建了由碎石、陶粒、玻璃轻石、HDPE和PVC排水板5种排水材料组成的佛甲草轻型种植屋面模拟试验平台(室内自然状态),测定了各材料处理土壤以及土壤底部空气的温、湿度。结果表明:土壤湿度在少雨季节受到不同排水材料的显著影响,而在雨量充沛的季节差异不显著。在干旱月份,与碎石处理相比,具有蓄水性能的4种排水材料(陶粒、玻璃轻石、HDPE和PVC排水板)有明显的抗旱优势,平均土壤湿度提高了约35%;然而,这4种材料的蓄水量大小对处理之间的土壤湿度没有显著影响;另外,材料的排水性能对土壤湿度有显著影响,通水量大的HDPE排水板在雨后初期土壤湿度显著小于其他材料。土壤(空气)温度没有受到材料蓄水性能的影响。轻型种植屋面土壤热湿环境的变化不完全由材料蓄水性能所决定;同时,其具有明显的保温(冬季夜间)隔热(全年白天)作用,且热工性能存在季节性和日内差异。     

Investigation and numerical modelling of roof drainage systems under extreme events

In April 2003 the UK Engineering and Physical Sciences Research Council (EPSRC) and a diverse group of interested parties began funding a number of major projects looking at the impacts of climate change on the built environment, transport and utilities. One of these projects, entitled AUDACIOUS, is concerned with the impact of climate change on all aspects of urban drainage systems. The main objective of this project is to investigate key aspects of the effects of climate change on existing drainage in urban areas, and hence provide tools for drainage managers and operators to adapt to uncertain future scenarios. A major element of this work is the development of a set of numerical models to simulate the performance of urban drainage systems under the type of extreme rainfall events associated with climate change. Once developed, it is intended to utilise such models in a diagnostic design capacity, to assist in the formulation of strategies to improve the performance of new and existing urban drainage systems under different climate change scenarios. This paper details the work that has been undertaken at Heriot-Watt University as part of the AUDACIOUS project. To date, this has involved the development of a numerical model to simulate the performance of roof drainage systems (both conventional and siphonic) under extreme rainfall events. The necessary experimental work is described, and the development of the model is detailed. Comparisons between model output and laboratory data are illustrated. Finally, conclusions are drawn regarding the progress to date, and plans for the next stage of the project are outlined.     

屋面外排水系统与建筑立面造型融合的探究

通过实例分析,探讨了屋面外排水系统与建筑立面造型的关系,针对屋面外排水系统与建筑有机融合提出了几点设计思路,以期创造完美的建筑整体效果。     

Surface and inner temperature attainment of flat roof systems in hot-dry climate

Near-black or dark brown roofing membranes can develop surface temperatures of over 95°C when applied as a finish over thermally insulated flat roofs, the author reports and recommends that lighter surface colours should be considered.     

大型建筑屋面雨水的排放和收集

结合浦东由由国际广场等多个大型公共建筑,通过比较重力排水系统和虹吸压力流排水系统的各自特点,说明(虹吸)压力流排水系统运用在大型公共建筑中的优势和适用范围。     

蚁群算法在雨水管道系统优化设计中的新尝试

引入一种新的优化设计方法——蚁群算法,并探讨将该法应用于雨水管道系统的优化设计.通过实例说明蚁群算法的过程,并与遗传算法进行比较,表明蚁群算法在给排水管网设计中有较为广阔的应用前景.     

Pressure transient suppression in drainage systems of tall buildings

ABSTRACT

The suppression of pressure transients in building drainage systems is essential for reducing cross-contamination by the spread of pathogens. The topic is now much better understood due to work following the invention of the first drainage-specific positive-pressure transient-attenuation device in the year 2000. The present research addresses the attenuation of much larger problematic air-pressure transients found in tall buildings. The development of a new technique is described for the attenuation of positive air pressure transients of approximately 2000?mm water gauge (wg) (20?kPa) for which there is currently no means to alleviate. The performance of the new technique was validated by numerical simulation and full-scale test-rig experiments. The full-scale test rig represented a 44-storey building with a 150?mm main drainage stack. The pressure wave generator applied a 2000?mm wg pressure transient from a large accumulator compressor delivering 270 litres of air at 10 bar pressure. This resulted in a capacity of 2700 litres of air at atmospheric pressure delivered into the system within 0.2?s. Results show that a prototype device using the new technique is capable of reducing the applied pressure transient by 88%, rendering it harmless and returning the system to normal operation in a matter of seconds.     

System interactions of stormwater management using sustainable urban drainage systems and green infrastructure

This study explores system interactions of stormwater management solutions using Sustainable Urban Drainage System (SuDS) and Green Infrastructure (GI) within the wider urban landscape. A series of interdependencies between urban components relating to stormwater management are identified. These include physical interdependency, geographical interdependency, cyber interdependency and logical interdependency, as defined by Peerenboom (2001). Stormwater management using SuDS/GI are viewed according to their Hydrological, Ecological and the Built Environment functions during events up to the design rain (non-flood condition) and during controlled exceedance and uncontrolled inundation (flood condition). The inclusion of SuDS/GI into the urban fabric is shown to modify urban functional and relational interdependencies under both these conditions. Within the context of the UK, there are fragmented responsibilities across planning scales created by SuDS/GI solutions which have not addressed the relational complexities that exist between agencies and competent authorities. The paper identifies the key barriers towards effective adoption of SuDS/GI within the context of the UK as physical barriers, perception/information barriers and organisational barriers.     

建筑排水系统立管水力特征

为了防止有害有毒气体进入室内,介绍了排水立管的水流特点,分析了立管中的水流状态和影响立管内压力波动的因素,提出了改善压力波动的措施,从而保证室内的空气品质,并对工程实际具有指导意义。