某19层写字楼给排水毕业设计(图和设计说明全套).doc 70页

'某19层写字楼给排水毕业设计摘要本设计的主要任务是苏州市吴越写字楼建筑给水排水工程设计，设计的主要内容包括：建筑给水系统、建筑排水系统、建筑雨水系统、消火栓给水系统和自动喷淋系统的设计。本建筑地下2层，地上19层，建筑物总高度为71.8m。其中一、二层为营业厅；三至十九层为大空间办公。市政给水管网常年提供的资用水头为0.40MPa，经技术经济比较，室内给水系统拟采用分区给水方式。初步拟定该建筑给水系统分二区：一至八层为低区，由市政管网直接供水；九层至设备层为高区，由直联无负压给水设备供水。建筑排水系统采用合流制，所有的污废水经化粪池处理后排入下水道。建筑雨水系统采用内排水的排水方式。消火栓给水系统分为室内消火栓给水系统和室外消火栓给水系统，消火栓的布置范围包括各楼层、消防电梯前室和屋顶检验用。消火栓保护半径为23m。建筑内喷头数量约1865个，设3组湿式报警阀，报警阀后管网为枝状网，每层设水流指示器。关键词：建筑给水系统，排水系统，消火栓系统，自动喷淋系统AbstractThemaintaskofthisdesignisthewatersupplyanddrainagedesignofwuyueofficebuildinginSuZhou.Thecontentofmydesignincludesthedesignofthebuildingwatersupplysystem,thebuildingwaterdrainagesystem,thebuildingstorm-watersystem,thehydrantwatersupplysystemandtheautomaticsprinklersystem.Thebuildinghas2floorsundergroundand24floorsoverground.Theheightofthebuildingis71.8m.Thefirst～thesecondfloorareusedforbusiness.Thethirdfloor～the19thfloorareusedasthebigspaceoffice.70 Themunicipalwatersupplypipingcanprovide0.40Mpahead.Afterthecomparisonoftechnicalityandeconomy,interiorwatersupplysystemintendstoadoptsubareawatersupply.Preliminarystudyoutthatbuildingwatersupplysystemisdividedtwoareas:1～8floorsarelowarea.Thepipenetworksupplieswaterdirectlyfrommunicipalwatersupplypiping;9～equipmentfloorsarehigharea.Watersupplyissuppliedbynonegativepressurewaterequipment.Thebuildingwaterseweragesystemadoptconfluence.Allwastewaterenterdrainviaaseptic-tank.Thebuildingstorm-watersystemadoptsinnerdraining.Hydrantwatersupplysystemincludesinteriorhydrantwatersupplysystemandoutsidehydrantwatersupplysystem.Hydrantarrangingrangeincludeseverystorey,theroominfrontoffireelevatorandroofforcheck.Thehydrantprotectsaradiusof23m.Thenumberofsprinklerheadsinthebuildingisabout1865.Theautomaticsprinklersystemsetup3groupswateryalarmvalve.Behindthealarmvalve,thepipingissetasbranch.Everystoreysetwaterflowindicator.Keywords：thebuildingwatersupplysystem,waterdrainagesystem,hydrantwatersupplysystem,thesprinklersystem70 第一章绪论一、设计题目苏州市吴越写字楼建筑给水排水工程二、设计的目的及意义毕业设计的目的是培养学生综合运用所学的基本理论、基本知识和基本技能，分析解决实际工程问题，培养学生对给排水工程专业及相关知识的综合运用能力和工程实践能力，增强学生的工程意识。通过毕业设计，使学生熟悉掌握给排水工程设计程序、方法和技术规范，提高对给排水工程设计的计算、图表绘制、计算说明书的编写；树立正确的设计思想，培养学生严肃认真的科学态度和严谨求实的科学作风，独立思考问题的能力及与他人合作的团队精神；树立正确的工程观、生产观、经济观和全局观。三、设计任务与内容1、收集相关资料，查阅相关规范，并熟悉规范条文。2、通过技术经济比较，优选设计方案。3、进行整个建筑的给水排水工程设计，要求达到施工图设计要求；具体包括室外总平面布置图，建筑给水（含消防给水、热水给水）设计，建筑排水设计，雨水排水设计，水表、泵和水箱的选型以及设备房的布置。4、撰写设计计算说明书。四、基本要求除了按时独立完成所规定的设计任务与内容外，还必须满足以下几项基本要求：1、毕业设计说明书（或论文）应包括工程设计的主要原始资料、方案确定、给水排水方式选择的分析说明、设计计算与相关简图、主要参考文献资料等。要求内容系统完整，计算正确，论述简洁明了，文理通顺，数据可靠，图表设计合理详实，装订整齐。70 撰写格式应符合学校教务处相关规定。2、毕业设计图纸应能较准确地表达设计意图，图面力求布局合理正确清晰，符合制图标准，专业规范及有关规定，用工程字注文。所有图纸应基本达到施工图要求。3、毕业设计中要学会计算机绘图，熟悉CAD绘图的基本命令和方法，按照制图标准、专业规范及有关规定，设计成果应为计算机绘图并打印输出。五、原始资料（一）建筑概况苏州市一19层写字楼，建筑面积约20000m2，建筑高度为71.8m，地下2层（地下室）、地上19层。负二层内为车库、电梯井、设备房（包括水泵房）和贮水池，负一层内为物业管理办公室和设备房，地上一层为门厅、营业厅，二层为营业厅，三层～十九层为为大空间办公室，屋顶设有电梯机房、水箱间。负二层层高3.90m，负一层层高5.40m，地上一层层高5.40m，二层层高6.00m，三层～十九层层高均为3.20m、电梯机房、水箱间的层高均为6.00m。室内、外地坪高差0.90m。建筑物每层均设有卫生间，卫生间内有蹲便器、小便器、洗手盆，等。（二）室外给、排水管道建筑物西、南侧各有1根DN400的市政给水干管，管顶埋深为1.0m，常年提供的资用水头为0.40MPa。市政给水干管不允许直接抽水。市政排水管位于建筑物的南侧，污水排水管1根，管径为DN500，管顶埋深为1.6m；雨水排水管1根，管径为DN800，管顶埋深为2.1m。（三）建筑条件图楼层平面图、剖面图、立面图。（四）设计内容建筑生活给水系统设计；建筑消防给水系统设计（包括消火栓系统、自动喷水灭火系统）；建筑排水系统设计；建筑雨水系统设计。六、进度安排70 第一周，查阅资料，熟悉规范条文及毕业设计原始资料；翻译一篇相关外文资料。第二周，确定设计方案，绘制方案图；第三至六周，各系统设计计算；第七至十一周，施工图绘制；第十二周，整理、修改毕业设计成果；第十三周，毕业答辩。七、设计成果1、设计说明书和计算书（含中、英文摘要）；2、绘制总平面布置图，各层管道平面布置图，给水与排水系统图，卫生间、管道井管道布置详图，设备房、水箱间布置图；3、一篇外文资料翻译，字数不少于5000字。70 第二章设计计算说明书一、建筑生活给水系统（一）给水方式市政给水管网常年可提供的资用水头为0.4MPa，建筑高度为71.8m，市政水压不能满足建筑内部用水要求，应考虑二次加压。经经济技术比较，室内给水拟采用分区给水方式。（二）给水分区70 图2.1.1给水分区图该建筑共十九层，初步拟定该建筑供水分为两个区：低区为1～8层，由市政管网直接供水；高区为9～19层，由供水，直联无负压给水设备设于负二层水泵房内。（三）给水系统的组成本建筑的给水系统由引入管、水表节点、给水管道、给水附件、直联无负压给水设备等组成。（四）给水管道布置与安装1、各层给水管道采用暗装敷设，管材均采用UPVC管，采用承插式接口，用弹性密封圈连接。2、管道外壁距墙面不小于150mm，离梁、柱及设备之间的距离为50mm，立管外壁距墙、梁、柱净距为20—25mm。3、给水管与排水管道平行、交叉时，其距离分别大于0.5m和0.15m，交叉给水管在排水管的上面。4、立管通过楼板时应预埋套管，且高出地面15—20mm。5、在立管横支管上设阀门，管径DN>50mm时设闸阀，DN<50mm设截止阀。6、引入管穿地下室外墙设套管。7、在进户管上安装水表，统一计量水量。8、给水横管设0.003的坡度，坡向泄水装置。9、贮水池采用钢筋混凝土，贮水池上部设人孔，基础底部设水泵吸水坑。为保证水质不被污染，水池底板做防水处理。10、所有水泵出水管均设缓闭止回阀，除消防泵外其他水泵均设减震基础，并在吸水管和出水管上设橡胶接头。（五）给水系统的设计计算1、最高日用水量与最高时用水量式中——最高日用水量，L/d；——最高日生活用水定额；70 N——用水单位数。=式中——最高时用水量，L/h；T——用水时间，h；——时变化系数。最高日用水量与最高时用水量的计算结果，见表2.1.1。用水量计算表表2.1.1序号用水类别用水定额用水单位N用水时间T时变化系数最高日用水量(m3/d)最高时用水量(m3/h)1停车库（-2F）3L/（m3·次）1700m28h1.05.100.642营业厅（1-2F）20L/（m3·d）2600m212h252.008.673屋顶花园（3F）2L/（m3·次）850m24h1.01.700.434办公楼（3-8F）50L/（人·d）325人10h1.316.252.105小计75.0511.846办公楼（9-19F）50L/（人·d）535人10h1.326.753.57屋顶花园（设备层）2L/（m3·次）280m24h1.00.560.148合计102.3615.489未预见按合计的20%计24h120.470.8510总计122.8316.332、水力计算（1）管段设计秒流量的计算按下式计算：（该建筑的系数均为1.5）所以：（2）低区给水管道水力计算低区共十层，低区最不利管路可能为供1-8层厕所的给水管道GL1或GL2，比较如下，其水力计算草图见图2.1.2。70 图2.1.2低区最不利管路水力计算草图70 水力计算结果见表2.1.2、表2.1.3，表2.1.4。低区管路水力计算表（JL1-1）表2.1.2管段编号卫生器具名称、当量、数量设计秒流量qgL/s管径DNmm流速Vm/s单阻IkPa/m管段长度Lm沿程水头损失i·LkPa自至洗手盆0.5拖布盆1.0大便器0.6当量总数Ng1210.50.1200.50.2490.820.2042321.00.2200.990.8990.850.7643431.50.3250.790.4045.052.03848312.50.47320.720.2452.950.723893134.30.62320.940.4053.451.3979106268.60.88400.860.2693.200.859101193912.91.08401.060.393.201.24911121241217.21.24500.750.1543.200.49412131551521.51.39500.840.193.200.60713141861825.81.52500.920.2256.001.34914152172130.11.65500.990.2595.401.40015162482434.41.76501.060.2931.800.5281617301030431.97501.180.360259.009沿程水头损失总和Σhy20.621低区管路水力计算表（JL1-2）表2.1.3管段编号卫生器具名称、当量、数量设计秒流量qgL/s管径DNmm流速Vm/s单阻IkPa/m管段长度Lm沿程水头损失i·LkPa自至洗手盆0.5拖布盆1.0大便器0.6当量总数Ng5610.60.12200.60.3491.150.4026721.20.24250.630.2671.150.3077831.80.36250.950.5651.550.876893134.30.62320.940.4053.451.3979106268.60.88400.860.2693.200.859101193912.91.08401.060.3903.201.24911121241217.21.24500.750.1543.200.49412131551521.51.39500.840.1903.200.60713141861825.81.52500.920.2256.001.34914152172130.11.65500.990.2595.401.40015162482434.41.76501.060.2931.800.5281617301030431.97501.180.36025.09.009沿程水头损失总和Σhy18.47770 低区管路水力计算表（JL2）表2.1.4管段编号卫生器具名称、当量、数量设计秒流量qgL/s管径DNmm流速Vm/s单阻IkPa/m管段长度Lm沿程水头损失i·LkPa自至洗手盆0.5大便器0.6小便器0.5当量总数Ng1210.60.12200.60.3491.120.3912321.20.24250.630.2672.850.76134121.70.34250.890.5090.950.48345222.20.44320.670.2131.050.224562223.20.54320.810.3093.351.034674446.40.76321.150.5853.201.873786669.60.93400.910.2973.200.9528988812.81.07401.050.3873.201.24091010101016.01.2401.180.4773.201.525101112121219.21.31500.790.1716.000.548111214141422.71.43500.850.1975.401.183121316161625.61.52500.910.2231.801.2051314202020321.70501.020.274339.050沿程水头损失总和Σhy20.469（3）高区给水管道水力计算高区为9-19层，共十一层，采用直联无负压供水设备供水，高区最不利给水管路水力计算草图见图2.1.3。70 图2.1.3高区给水管路水力计算草图70 水力计算结果见表2.1.5。高区最不利管路水力计算表（JL5）表2.1.5管段编号卫生器具名称、当量、数量设计秒流量qgL/s管径DNmm流速Vm/s单阻IkPa/m管段长度Lm沿程水头损失i·LkPa自至洗手盆0.5拖布盆1.0大便器0.6当量总数Ng1210.50.1200.50.2490.820.2042321.00.2200.990.8990.850.7643431.50.3250.790.4045.052.03845312.50.47320.720.2452.950.723563134.30.62320.940.4053.451.397676268.60.88400.860.2693.200.8597893912.91.08401.060.3903.201.249891241217.21.24500.750.1543.200.4949101551521.51.39500.840.1903.200.60710111861825.81.52500.920.2253.200.71911122172130.11.65500.990.2593.200.82912132482434.41.76501.060.2933.200.93913142792738.71.87501.120.3273.201.0461415301030431.97501.180.3603.201.153151633113347.32.06700.780.1273.200.407161736123651.62.16700.820.13857.47.920沿程水头损失总和Σhy21.3483、楼层引入管的计算与选择（1）-2～8层营业厅及办公室-2～8层营业厅及办公室的引入管设计秒流量＝1.97L/s＝7.09m/h。引入管管径为DN50，流速v＝1.18m/s，i＝0.36kPa/m。（2）9～19层办公室9～19层办公室的引入管接至直联无负压给水设备。9～19层办公室的引入管设计秒流量＝2.16L/s＝7.42m/h。引入管管径为DN70，流速0.78m/s，i＝0.127kPa/m。4、室外给水管网、进户水表的计算与选择室外给水管网布置成环状布置，在建筑物南侧布置进户管与市政给水管连接，进户管上安装水表。图2.1.4为室外给水管道水力计算草图。70 （1）室外给水管道室外给水管道设计流量由供给建筑物的生活水量、消防水量二部分组成。1）生活水量，∑=113.0,α=1.5＝11.48/h图2.1.4室外给水管道的水力计算草图2）消防水量市政给水管上的2个室外消火栓能满足本建筑的的室外消防给水水量要求30L/s，则建筑室外给水管主要考虑室内消防用水量要求，按消防贮水池进水量计算。＝48.6/h3）＝+＝11.48/h+48.6/h＝60.08/h室外给水管呈环状布置，双向供水，进户管2根，则管道计算流量按事故用水考虑70 1根进户管停水或双向供水因局部故障变为单向供水），取70％，即42.06/h。室外给水管管径为DN125，流速v＝1.35m/s，i＝0.0326kPa/m（2）进户管上水表进户管上水表选用LXL-80N水平螺翼式水表，过载流量为80/h，常用流量为40/h水表特性系数平时供水时水表水头损失11.48/640＝0.21kPa＜12.8kPa消防供水时水表水头损失63.58/640＝6.32kPa＜29.4kPa5、低区水压校核图2.1.2中的1点为最不利点，其所需的水压为：1）静水压＝27.4+0.8+1.0=29.2m＝292kPa2）室内计算管路水头损失＝（1+30%）∑＝1.3×20.621=26.807kPa（局部水头损失取沿程水头损失的30％）3）室外计算管路水头损失＝（1＋10％）∑＝1.1×0.0326×100＝3.586kPa（局部水头损失取沿程水头损失的10％）4）进户管上水表水头损失=0.21kPa5）1点所需的最低工作压力=50kPa6）＝372.6kPa市政给水管的资用水头=0.40MPa=400kPa>H,满足低区水压要求。6、高区水压校核图2.1.3中的最不利点为1点，其所需的水压为：1）静水压＝67.0+0.8+1.0=68.8m＝688kPa2）室内计算管路水头损失＝（1+30%）∑＝1.3×21.348=27.752kPa（局部水头损失取沿程水头损失的30％）3）室外计算管路水头损失＝（1＋10％）∑＝1.1×0.0326×100＝3.586kPa70 4）进户管上水表水头损失=0.21kPa5）1点所需的最低工作压力=50kPa6）＝769.55kPa选用的直联无负压给水设备的扬程=77m=770kPa>H,满足高区水压要求。7、直联无负压给水设备的选择直联无负压设备用于高区供水。（1）设计流量取高区最高时用水量15.48（2）选用设备设备型号：KDGW（1）24-77（流量24，扬程77m）水泵：CR15-6台数：2台，一用一备功率：5.5KW无负压缓冲罐：SQW800×1950总容积：770L稳压补偿器：BCQ380×450总容积：50L智能控制系统：KDC-WPJ-2-5.5二、建筑消防给水系统本建筑应设有室内、外消防给水系统，即室外消火栓给水系统、室内消火栓给水系统和自动喷水灭火给水系统。（一）、室外消火栓给水系统室外消火栓给水系统的设计流量为30L/S。每个消火栓用水量按10～15L/S计算,采用两个地上式室外消火栓,室外消火栓应沿建筑物均匀布置，距建筑物外墙的距离不宜小于5m，不宜大于40m；距路边的距离不宜大于2m。（二）、室内消火栓给水系统室内消火栓给水系统的设计流量为40L/S，每根消防竖管最小设计流量为15L/S，每支水枪最小设计流量为5L/S。火灾延续时间为3h。70 1、系统组成室内消火栓给水系统不分区，采用消防贮水池、消火栓泵和消防水箱联合供水的临时高压给水系统，由消防贮水池、消火栓泵、消火栓给水管、减压孔板、室内消火栓、水枪、水龙带、消防水箱、消防水箱进水泵、增压设施、水泵结合器等组成。消火栓泵直接从消防贮水池吸水，消防水箱和增压设备保证初期灭火的消防水量、水压要求，消防水箱进水泵由消防贮水池吸水后供消防水箱。消防贮水池贮存室内消火栓给水系统和自动喷水灭火给水系统的消防用水，并提供消防水箱的消防贮水量，贮水容积为455。消火栓泵2台，一用一备，设计流量46.08L/s，扬程1.08Mpa。室内消火栓口径为65mm，单出口，每个消火栓处设直接启动消火栓泵的按钮。屋顶设一个实验消火栓，置于设备房内。水枪喷嘴口径19mm，充实水柱为12m。水龙带为内衬胶，直径65mm，长度25mm.消火栓给水管网采用焊接钢管，焊接连接。消防水箱设于屋顶水箱间内，贮水容积按21计。消防水箱进水泵2台，一用一备，设计流量2.5L/s。消防水箱内安装液位信号仪，自控控制进水泵的启闭（低液位启动，高液位关闭）。增压设施设于屋顶设备房内，主要由增压泵和气压罐组成。增压泵2台，一用一备，设计流量为5L/S。气压罐为隔膜式，调节水容量为300L。SQ150地上式水泵结合器5个，每个结合器的供水流量：10～15L/S。2、消火栓布置消火栓保护半径R=C*Ld＋Ls=0.8*25+3=23m同一层布置的消火栓的最多个数为9个。3、设计计算（1）消火栓栓口径为65cm，水枪口径为19cm，衬胶水龙带长度为25cm，水枪充实水柱长度为12.0m。水枪出口所需水压：=70 =1.2112/（1-0.0971.2112）=16.90m=169.0kPa水枪喷嘴出流量=（）=（1.57716.9）=5.16L/s＞5.0L/s水龙带水头损失==0.0172255.16=1.14m=11.4kPa消火栓栓口所需压力：=++=169.0+11.4+20.0=200.4kP=20.04m（2）消火栓给水系统最不利管路水力计算图2.2.1为消火栓给水系统最不利管路水力计算草图。图中，最不利消防竖管为0-3管段，出水枪数为3，相邻消防竖管为0’-4和，出水枪数分别为3和2，最不利点为0点。70 图2.2.1消火栓给水系统最不利管路水力计算草图表2.2.1为消火栓给水系统最不利管路水力计算表。0点的水枪射流量：＝5.16L/s0点的消火栓栓口压力：0点与1点的消火栓间距：0～1管段的水头损失：1点的水枪射流量：1点的消火栓栓口压力：＝26.09m70 5.96L/s1点与2点的消火栓间距：1～2管段的水头损失：2点的水枪射流量：2点的消火栓栓口压力:=29.40m6.36L/s消火栓给水系统最不利管路水力计算表表2.2.1管段编号设计流量Q（L/s）管径DN(mm)流速V（m/s）单阻ikPa/m管段长度L(m)=ikPa备注自至015.161000.580.0666.00.401、水力计算时，以树状管网进行，0-1管段的水平段视为实现环状供水的保证措施以及增压设备向最不利消火栓供水的水平管线。2、8-7管段为消防水箱进水泵向消防水箱供水的管线，管材为UPVC给水管，设计流量去生活水箱进水泵的设计流量。3、10-11管段为消防水池进水管，管材选用UPVC给水管。125.16+5.96＝11.121001.280.2973.20.952311.12+6.36＝17.481002.020.68770.848.643417.481500.930.10315.01.55452×17.48＝34.961501.850.3715.52.045634.96+11.12＝46.081502.440.61924.915.41最不利管路沿程水头损失总和∑68.99095.01000.950.17740.07.08872.5501.180.69684.558.8110110.950.17725.04.4370 各层消火栓栓口出水压力计算结果表2.2.2楼层号上下层间消防竖管设计流量Q（L/s）上下层间消防竖管单阻i（kPa/m）上下层间消防竖管长度L(m)上下层间消防竖管沿程水损（kPa）楼层消火栓栓口压力（kPa）设备层200.4195.160.08046.00.48200.4+3.20×10+0.48＝232.88＜5001811.120.33123.21.06232.88+3.20×10+1.06＝265.94＜5001717.480.8213.22.63265.94+3.2×10+2.63＝300.57＜5001617.480.8213.22.63300.57+3.2×10+2.63＝335.20＜5001517.480.8213.22.63335.20+3.2×10+2.63＝369.83＜5001417.480.8213.22.63369.83+3.2×10+2.63＝404.46＜5001317.480.8213.22.63304.46+3.2×10+2.63＝439.09＜5001217.480.8213.22.63439.09+3.2×10+2.63＝473.72＜5001117.480.8213.22.63473.72+3.2×10+2.63＝508.35＞5001017.480.8213.22.63508.35+3.2×10+2.63＝542.98＞500917.480.8213.22.63542.98+3.2×10+2.63＝577.61＞500817.480.8213.22.63577.61+3.2×10+2.63＝612.24＞500717.480.8213.22.63612.24+3.2×10+2.63＝646.87＞500617.480.8213.22.63646.87+3.2×10+2.63＝681.50＞500517.480.8213.22.63681.50+3.2×10+2.63＝716.13＞500417.480.8213.22.63716.13+3.2×10+2.63＝750.76＞500317.480.8213.22.63750.76+3.2×10+2.63＝785.39＞500217.480.8216.04.93785.39+6.0×10+4.93＝823.32＞50070 117.480.8215.44.43823.32+5.4×10+4.43＝881.75＞500-117.480.8215.44.43881.75+5.4×10+4.43＝940.18＞500-217.480.8213.93.20940.18+3.9×10+3.20＝982.38＞500（3）消火栓泵的选择1）设计流量＝46.08L/s＝165.89/h2)设计扬程最不利管路水头损失静水压＝80.0m＝800kPa最不利点的消火栓栓口压力200.4kPa＝1081.97kPa＝108.2m选用2台XBD11/45-150DL×5多级立式消防泵，一用一备，水泵性能参数：Q=126～200，H＝108～135m，n＝1450r/min，N＝90KW。（4）减压孔板的选择表2.2.2为各层消火栓栓口压力的计算结果楼层消火栓栓口压力大于0.50MPa时，应设减压装置。减压设施选用减压孔板（不锈钢材质），在消火栓的连接管上设置减压孔板，将表中消火栓栓口压力大于0.50MPa的减至0.40MPa。消火栓连接管管径为DN65，设置减压孔板的楼层及其减压孔板的规格，见表2.2.3减压孔板规格表2.2.3楼层号111098765孔板减压值8.3542.9877.61112.24146.87181.50216.13孔口直径30242624242220孔板数量1121333楼层号4321-1-2孔板减压值250.76285.39323.32381.75440.18482.38孔口直径222220202220孔板数量455677（5）消防水箱、消防水箱进水泵、增压设施的选择70 1）消防水箱以贮存10min的室内消防水量计算时，消防水箱贮水容积10×（46.08＋20.23）×60×＝39.79，容积偏大，故以“一类公共建筑不应小于18”的规范规定取值。由于液位信号仪的液位信号转换为水泵的启、闭有一定的时间差，平时因管路渗漏、消防给水系统测试等因素而导致水箱内液位降低时，为确保平时消防水箱内18的贮水容积不被动用，将消防水箱的贮水容积定为21，即：消防水箱进水泵的低液位启动、高液位关闭的自动运行控制，以最小贮水量为18所对应的液位为低液位，以最大贮水量21所对应的液位为高液位。消防水箱规格：（有效水深为1.75m）消防水箱置于屋顶水箱间内，水箱箱内底标高为72.5m，箱内顶标高为74.6m。水箱间室内地坪标高71.8m，水箱架空高度为0.7m，箱顶上的净空高度大于0.6m。2）消防水箱进水泵消防水箱进水泵的设计流量和扬程为：15.48≥768.221kPa＝77m选用两台50DL×6多级立式泵，一用一备，水泵性能参数：Q＝9.0～16.2，H＝63.6～79.8m，n＝1450r/min，N＝5.5KW。3)增压设施消防水箱内标高为72.5m～74.25m，最不利点消火栓的标高为66.9m，则消防水箱提供给最不利点消火栓的静水压力为5.6～7.35m，即56～73.5kPa，应设增压设施。增压设施的最小工作压力＝200.4＋1.1×7.08+（66.9-72.5）×10＝152.19kPa（相对压力）气压罐的取0.8，则：增压设施的最大工作压力=（＋100）/0.8－100＝215.24kPa（相对压力）增压泵的设计工况电应满足：a、流量为5L/s时，扬程不小于152.19kPa70 b、流量小于5L/s时，扬程能达到215.24kPa增压泵选用两台50DL×2多级立式泵，一用一备，水泵性能参数：Q＝3L/s时，H＝250.0kPa，Q＝5L/s时，H＝180.0kPa，n＝1450r/min，N＝3KW。气压罐为隔膜式，调节水容量300L,容积附加系数1.05，气压罐总容积V为：V＝1.05×300/（1-0.80）＝1575L气压罐规格：Ø1200mm×1500mm(6)消防贮水池消防贮水池进水管选用UPVC给水管，管径DN125,流速取1.0m/s，流量为13.50L/s（48.6/h）消防贮水池贮水容积V包括：1)用于室内消火栓系统和喷淋系统灭火时的消防贮水量（3×46.08+1×20.23-3×13.5）×3600/1000＝424.692）用于提供消防水箱的消防贮水量则：V=424.69＋21＝445.69消防贮水池规格：L×B×H=11000mm×18000mm×2300mm（有效水深为2.0m），贮水容积为455.00。消防贮水池和消防泵房相毗邻。消防贮水池池内底标高：-9.3m，池内顶标高：-7.0m，吸水坑坑内底标高：-9.8m。7）水泵接合器室内消火栓系统的消防设计流量为46.08L/s，选用5个SQ150地上式水泵结合器，每个结合器的流量为10～15L/s。（三）自动喷水灭火给水系统该建筑为一类建筑，火灾危险等级等级为中危险级Ⅰ级，自动喷水灭火给水系统采用湿式自动喷水灭火系统（简称：喷淋系统），设计喷水强度为6L/（min·m2），作用面积160m2，喷头工作压力0.08MPa。火灾延续时间为1h,则自喷系统消防用水量=160×6/60=16L/S。1、系统组成70 喷淋系统有消防贮水池、喷淋泵、湿式报警阀组、喷淋给水管、减压孔板、水流指示器、玻璃球喷头、消防水箱、消防水箱进水泵、增压设备、水泵结合器等组成。喷淋泵直接从消防贮水池吸水，消防水箱和增压设备保证初期灭火的消防水量、水压要求，消防水箱进水泵由消防贮水池吸水后供消防水箱。喷淋系统的消防贮水池、消防水箱进水泵，分别与室内消火栓给水系统的消防贮水池、消防水箱、消防水箱进水泵共用。喷淋泵两台，一用一备，设计流量20.23L/s，扬程1.09MPa。建筑物每层均布置了玻璃球喷头、水流指示器。喷头布置形式以正方形、矩形为主，喷头动作温度为68℃。湿式报警阀组，共3个，设于地下室水泵房内，分别控制-2～1层，2～9层，10～设备层的喷头。每个报警阀组包括报警阀，压力开关，延时器，水力警铃，泄水装置等部件。喷淋给水管采用热浸镀锌钢管。增压设施设于屋顶设备房内，主要由增压泵和气压罐组成。增压泵2台，一用一备，设计流量1L/s。气压罐为隔膜式，调节水容量150L。2、设计计算70 图2.2.2喷淋系统管路水力计算草图（1）作用面积与喷水强度根据19层喷头的平面布置情况，取喷淋系统最不利工作作用面积F＝163.2。作用面积内的喷头，共17只。每个喷头的喷水量70 作用面积内的设计流量理论设计流量1.24，介于1.15～1.30之间，符合要求。作用面积内的计算平均喷水强度：作用面积内最不利点处四个喷头所组成的保护面积的长度为：1.65+3.6+1.8＝7.05m宽度为：0.9+3.0+1.5＝5.4m＝7.05×5.4＝38.07每个喷头的平均保护面积＝38.07/4＝9.5每个喷头的平均喷水强度q＝80/9.5＝8.4＞6（2）水力计算系统有两条最不利管路，一条为喷淋泵以设计流量供水时所形成的，另一条为增压设施以不大于1.0L/s的初期灭火流量供水时所形成的，二种供水不应同时进行。表2.2.4为喷淋系统管路水力计算结果。为喷淋系统管路水力计算结果表2.2.4管段编号设计流量Q(L/s)管径DN(mm)流速系数流速V=（m/s）比阻A管段长度L(m)自至121.19251.8332.441.424.3673.622.32232.38321.0502.795.660.9393.619.13343.57321.0504.1912.740.9391.416.75455.95500.4703.1335.400.1113.011.795611.90700.2833.76141.610.0291.14.526717.85800.2044.07318.620.01211.042.067820.23800.2044.61409.250.0127.235.368920.231000.1152.54409.250.002723.525.9791120.231500.0531.20409.250.000388.010.80喷淋泵供水的最不利管路沿程水头损失总和Σ188.70121.0251.8331.831.04.3673.615.72231.0321.0501.051.00.9393.63.38341.0321.0501.051.00.9391.41.3170 451.0500.4700.471.00.1113.00.33561.0700.2830.281.00.0291.10.03671.0800.2040.201.00.01211.00.13781.0800.2040.201.00.0127.20.09891.01000.1150.121.00.002723.50.069101.01500.0530.051.00.000371.90.0210121.0400.8000.801.00.0445100.04.45增压设施供水的最不利管路沿程水头损失总和Σ25.52（3）喷淋泵的选择1）设计流量＝20.23L/s＝72.832）设计扬程高程差Z＝65.8+（5.4+3.9）＝75.1m最不利管路水头损失∑h＝（1+20%）∑＝1.2×188.70＝226.44kPa（局部水头损失取沿程水头损失的20％）水流指示器的水头损失＝20kPa湿式报警阀的水头损失＝20kPa最不利点处喷头额工作压力＝80kPa∑h+++=1097.4kPa＝109.74m选用两台XBD11/20-100DL×6多级立式消防泵，一用一备，水泵性能参数：Q=72～126，H＝102～130.2m，n＝1450r/min，N＝55KW。（4）增压设施的选择消防水箱最低水位标高为72.5m，最不利点处喷头的标高为65.8m。增压设施的最小工作压力＝80＋1.2×25.52＋20+20+（72.5－65.8）×10＝217.62kPa（相对压力）气压罐的取0.85，则：增压设施的最大工作压力=（＋100）/0.85－100＝273.67kPa（相对压力）增压泵的设计工况电应满足：a、流量为1L/s时，扬程不小于217.62kPab、流量小于1L/s时，扬程能达到273.67kPa增压泵选用两台40DL×2多级立式泵，一用一备，水泵性能参数：Q＝0.5L/s时，70 H＝280.0kPa，Q＝1L/s时，H＝250.0kPa，n＝1450r/min，N＝2.2KW。气压罐为隔膜式，调节水容量150L,容积附加系数1.05，气压罐总容积V为：V＝1.05×150/（1-0.85）＝1050L气压罐规格：Ø1000mm×1500mm（5）水泵接合器喷淋系统的设计流量为20.23L/s。选用2个SQ150地上式水泵接合器，每个接合器的流量为10～15L/s。三、建筑排水系统建筑排水系统分为生活排水系统和屋面雨水排水系统。生活污、废水合流排入市政污水排水管，屋面雨水排入市政雨水排水管。(一)、生活排水系统1、系统的选择由于市政排水集中至城市污水处理厂处理，本建筑的生活排水系统采用合流制，即：生活污、废水不进行局部处理，合流排出室外。地下室集水坑，设潜污泵排水。2、系统的组成生活排水系统由卫生器具、排水管道、检查口、清扫口、室外排水管道、检查井、潜水泵、集水井、化粪池等组成。潜污泵排水管管材为UPVC给水管。3、排水管道及设备安装要求（1）排水管材采用螺旋消音排水塑料管。（2）排水管与室外排水管连接处设置检查井，检查井距离建筑物的距离不小于3m，并与给水管引入管外壁的水平距离不得小于1.0m。（3）当排水管在中间竖向拐弯时，排水支管与排水立管、排水横管相连接时排水支管与横管连接点至立管底部的水平距离不小于1.5m；排水竖支管与立管拐弯处的垂直距离不得小于0.6m。（4）立管宜每2层设1个检查口。在水流转角小于135°的横干管上和连接两个以上大便器或连接三个及三个以上排水器具的支管上应设检查口或清扫口。（5）立管管径大于或等于110mm时，在楼板贯穿部位应设置阻火圈或张度不小于500mm的防火套管。管径大于或等于110mm的横支管与暗设立管相连接时，墙体贯穿部位应设置阻火圈或张度不小于300mm的防火套管，且防火套管的明露部分张度不宜小于200mm；防火套管、防火圈的耐火极限不宜小于贯穿部位的建筑结构的耐火等级。70 4、系统的设计计算（1）排水设计秒流量营业厅、办公室的排水设计秒流量（L/s）（2）排水管的水力计算排水管水力计算草图见图2.3.1。70 图2.3.1排水管水力计算草图70 1）横支管的水力计算：PL1表2.3.1管道编号卫生器具名称数量当量总数设计秒流量（L/s）管径De(mm)坡度i大便器拖布盆洗手盆4.51.00.31-214.51.501100.0262-329.02.401100.0263-8313.52.601100.0267-610.30.10750.0266-520.60.20750.0265-430.90.30750.0264-8131.90.63750.026PL2表2.3.2管道编号卫生器具名称数量当量总数设计秒流量（L/s）管径De(mm)坡度i大便器小便器洗手盆4.50.30.31-214.51.501100.0262-329.02.401100.0264-510.30.10750.0265-620.60.20750.0266-7210.90.30750.0267-3221.20.40750.026PL3表2.3.3管道编号卫生器具名称数量当量总数设计秒流量（L/s）管径De(mm)坡度i大便器洗手盆4.50.31-210.30.10750.0262-320.60.20750.0263-430.90.30750.0264-541.20.40750.0265-651.50.50750.0266-1061.80.60750.0267-814.51.501100.0268-929.02.401100.0269-10313.52.601100.02670 PL4表2.3.4管道编号卫生器具名称数量当量总数设计秒流量（L/s）管径De(mm)坡度i大便器小便器4.50.31-210.30.10750.0262-320.60.20750.0263-430.90.30750.0264-941.20.40750.0265-614.51.501100.0266-729.02.401100.0267-8313.52.601100.0268-9418.02.771100.0262）、立管计算PL1:立管接纳的排水当量总数为＝（13.5＋1.9）19＝292.6立管最下部管段排水设计秒流量6.63L/s查表，选用立管管径de125mm。设专用通气立管。PL2:立管接纳的排水当量总数为＝（9.0＋1.2）19＝193.8立管最下部管段排水设计秒流量5.68L/s查表，选用立管管径de125mm。设专用通气立管。PL3:立管接纳的排水当量总数为＝1.8＋13.5＝15.3立管最下部管段排水设计秒流量2.67L/s因有大便器，立管管径放大一号，选用de110mm，不设专用通气立管。PL4:立管接纳的排水当量总数为＝1.2＋18＝19.2立管最下部管段排水设计秒流量70 2.81L/s因有大便器，立管管径放大一号，选用de110mm，不设专用通气立管。3）、排出管、排水横干管计算图2.3.2排出管水力计算草图70 排出管计算表表2.3.5管道编号卫生器具名称数量当量总数设计秒流量（L/s）管径De(mm)坡度i大便器拖布盆小便器洗手盆4.51.00.30.3a-A4419.22.811250.015b-B3615.32.671250.015c-C383838193.85.681500.010d-D571957292.66.631500.010５、通气管计算TL1、TL2专用通气立管管径与排水立管管径相同，均为125mm。(二)、屋面雨水排水系统1、系统组成屋面雨水排水，采用雨水斗内排水的方式，排水管选用UPVC排水管，雨水斗选用87式，单斗布置。雨水通过雨水斗、雨水斗连接管、悬吊管、立管及埋地横管等，在地下层排出室外，接入市政雨水排水管。2、降雨强度设计重现期P取2年，降雨历时t采用5min，查有关资料，有=99mm/h3、屋面雨水汇水面积F的划分原则（1）屋面汇水面积应按屋面的水平投影面积计算。（2）高出屋面的侧墙的汇水面积计算，按侧墙面以及侧墙之间的平面位置与高度差，作调整系数为50%的汇水面积折算。4、雨水立管的布置（1）三层屋面划分为5个汇水区，布置5个雨水斗，雨水立管分别为YL1-YL5。（2）设备层屋面划分为2个汇水区，布置2个雨水斗，雨水立管分别为YL6、YL7。（3）屋顶划分为2个汇水区，布置2个雨水斗，雨水立管分别为YL8、YL9。5、水力计算（1）雨水量Q=（L/s）其中：屋面的径流系数取0.9，=99mm/h，则：70 （2）水力计算结果见表2.3.6雨水排水系统水力计算结果表2.3.6立管编号汇水面积F()雨水量Q（L/s）雨水斗立管排出管管径DN(mm)最大泄流量（L/s）管径de（mm）最大泄流量（L/s）管径de（mm）YL1370.49.261001611019110YL2360.89.021001611019110YL3652.3616.311503216042160YL4652.2216.311503216042160YL5807.0720.181503216042160YL689.252.231001611019110YL789.252.231001611019110YL889.252.231001611019110YL989.252.231001611019110YL1051.831.301001611019110YL1151.831.301001611019110YL1251.831.301001611019110YL1351.831.30100161101911070 第三章翻译Sealedbuildingdrainageandventsystems—anapplicationofactiveairpressuretransientcontrolandsuppressionAbstractTheintroductionofsealedbuildingdrainageandventsystemsisconsideredaviablepropositionforcomplexbuildingsduetotheuseofactivepressuretransientcontrolandsuppressionintheformofairadmittancevalvesandpositiveairpressureattenuatorscoupledwiththeinterconnectionofthenetwork"sverticalstacks.Thispaperpresentsasimulationbasedonafour-stacknetworkthatillustratesflowmechanismswithinthepipeworkfollowingbothappliancedischargegenerated,andsewerimposed,transients.Thissimulationidentifiestheroleoftheactiveairpressurecontroldevicesinmaintainingsystempressuresatlevelsthatdonotdepletetrapseals.Furthersimulationexerciseswouldbenecessarytoprovideproofofconcept,anditwouldbeadvantageoustoparallelthesewithlaboratory,andpossiblysite,trialsforvalidationpurposes.Despitethiscautiontheinitialresultsarehighlyencouragingandaresufficienttoconfirmthepotentialtoprovidedefinitebenefitsintermsofenhancedsystemsecurityaswellasincreasedreliabilityandreducedinstallationandmaterialcosts.Keywords:Activecontrol;Trapretention;TransientpropagationNomenclatureC+-characteristicequationscwavespeed,m/sDbranchorstackdiameter,mffrictionfactor,UKdefinitionviaDarcyΔh=4fLu2/2Dg70 gaccelerationduetogravity,m/s2KlosscoefficientLpipelength,mpairpressure,N/m2ttime,sumeanairvelocity,m/sxdistance,mγratiospecificheatsΔhheadloss,mΔppressuredifference,N/m2Δttimestep,sΔxinternodallength,mρdensity,kg/m3SuffixAappliancesideoftrapB70 branchlocalconditionsatnodeTtrapatmatmosphericpressureFfrictionRroomSsystemsideoftrapwwaterArticleOutlineNomenclature1.Introduction—airpressuretransientcontrolandsuppression2.Mathematicalbasisforthesimulationoftransientpropagationinmulti-stackbuildingdrainagenetworks3.Roleofdiversityinsystemoperation4.Simulationoftheoperationofamulti-stacksealedbuildingdrainageandventsystem5.Simulationsignconventions6.Waterdischargetothenetwork7.Surchargeatbaseofstack18.Sewerimposedtransients9.Trapsealoscillationandretention10.Conclusion—viabilityofasealedbuildingdrainageandventsystem1.Introduction—airpressuretransientcontrolandsuppression70 Airpressuretransientsgeneratedwithinbuildingdrainageandventsystemsasanaturalconsequenceofsystemoperationmayberesponsiblefortrapsealdepletionandcrosscontaminationofhabitablespace[1].Traditionalmodesoftrapsealprotection,basedontheVictorianengineer"sobsessionwithodourexclusion[2],[3]and[4],dependpredominantlyonpassivesolutionswhererelianceisplacedoncrossconnectionsandverticalstacksventedtoatmosphere[5]and[6].Thisapproach,whilebothprovenandtraditional,hasinherentweaknesses,includingtheremotenessoftheventterminations[7],leadingtodelaysinthearrivalofrelievingreflections,andthemultiplicityofopenrooflevelstackterminationsinherentwithincomplexbuildings.Thecomplexityoftheventsystemrequiredalsohassignificantcostandspaceimplications[8].Thedevelopmentofairadmittancevalves(AAVs)overthepasttwodecadesprovidesthedesignerwithameansofalleviatingnegativetransientsgeneratedasrandomappliancedischargescontributetothetimedependentwater-flowconditionswithinthesystem.AAVsrepresentanactivecontrolsolutionastheyresponddirectlytothelocalpressureconditions,openingaspressurefallstoallowareliefairinflowandhencelimitthepressureexcursionsexperiencedbytheappliancetrapseal[9].However,AAVsdonotaddresstheproblemsofpositiveairpressuretransientpropagationwithinbuildingdrainageandventsystemsasaresultofintermittentclosureofthefreeairpaththroughthenetworkorthearrivalofpositivetransientsgeneratedremotelywithinthesewersystem,possiblybysomesurchargeeventdownstream—includingheavyrainfallincombinedsewerapplications.Thedevelopmentofvariablevolumecontainmentattenuators[10]thataredesignedtoabsorbairflowdrivenbypositiveairpressuretransientscompletesthenecessarydeviceprovisiontoallowactiveairpressuretransientcontrolandsuppressiontobeintroducedintothedesignofbuildingdrainageandventsystems,forboth‘standard’buildingsandthoserequiringparticularattentiontobepaidtothesecurityimplicationsofmultiplerooflevelopenstackterminations.Thepositiveairpressureattenuator(PAPA)consistsofavariablevolumebagthatexpandsundertheinfluenceofapositivetransientandthereforeallowssystemairflowstoattenuategradually,thereforereducingthelevelofpositivetransientsgenerated.70 TogetherwiththeuseofAAVstheintroductionofthePAPAdeviceallowsconsiderationofafullysealedbuildingdrainageandventsystem.Fig.1illustratesbothAAVandPAPAdevices,notethatthewaterlesssheathtrapactsasanAAVundernegativelinepressure.(39K)Fig. 1. Activeairpressuretransientsuppressiondevicestocontrolbothpositiveandnegativesurges.Activeairpressuretransientsuppressionandcontrolthereforeallowsforlocalizedinterventiontoprotecttrapsealsfrombothpositiveandnegativepressureexcursions.Thishasdistinctadvantagesoverthetraditionalpassiveapproach.Thetimedelayinherentinawaitingthereturnofarelievingreflectionfromaventopentoatmosphereisremovedandtheeffectofthetransientonalltheothersystemtrapspassedduringitspropagationisavoided.2.Mathematicalbasisforthesimulationoftransientpropagationinmulti-stackbuildingdrainagenetworksThepropagationofairpressuretransientswithinbuildingdrainageandventsystemsbelongstoawellunderstoodfamilyofunsteadyflowconditionsdefinedbytheStVenantequationsofcontinuityandmomentum,andsolvableviaafinitedifferenceschemeutilizingthemethodofcharacteristicstechnique.Airpressuretransientgenerationandpropagationwithinthesystemasaresultofairentrainmentbythefallingannularwaterinthesystemverticalstacksandthereflectionandtransmissionofthesetransientsatthesystemboundaries,includingopenterminations,connectionstothesewer,appliancetrapsealsandbothAAVandPAPAactivecontroldevices,maybesimulatedwithprovenaccuracy.Thesimulation[11]provideslocalairpressure,velocityandwavespeedinformationthroughoutanetworkattimeanddistanceintervalsasshortas0.001 sand300 mm.Inaddition,thesimulationreplicateslocalappliancetrapsealoscillationsandtheoperationofactivecontroldevices,therebyyieldingdataonnetworkairflowsandidentifyingsystemfailuresandconsequences.Whilethesimulationhasbeenextensivelyvalidated[10],itsusetoindependentlyconfirmthe70 mechanismofSARSvirusspreadwithintheAmoyGardensoutbreakin2003hasprovidedfurtherconfidenceinitspredictions[12].Airpressuretransientpropagationdependsupontherateofchangeofthesystemconditions.Increasingannulardownflowgeneratesanenhancedentrainedairflowandlowersthesystempressure.Retardingtheentrainedairflowgeneratespositivetransients.Externaleventsmayalsopropagatebothpositiveandnegativetransientsintothenetwork.Theannularwaterflowinthe‘wet’stackentrainsanairflowduetotheconditionof‘noslip’establishedbetweentheannularwaterandaircoresurfacesandgeneratestheexpectedpressurevariationdownaverticalstack.Pressurefallsfromatmosphericabovethestackentryduetofrictionandtheeffectsofdrawingairthroughthewatercurtainsformedatdischargingbranchjunctions.Inthelowerwetstackthepressurerecoverstoaboveatmosphericduetothetractionforcesexertedontheairflowpriortofallingacrossthewatercurtainatthestackbase.Theapplicationofthemethodofcharacteristicstothemodellingofunsteadyflowswasfirstrecognizedinthe1960s[13].TherelationshipsdefinedbyJack[14]allowsthesimulationtomodelthetractionforceexertedontheentrainedair.Extensiveexperimentaldataallowedthedefinitionofa‘pseudo-frictionfactor’applicableinthewetstackandoperableacrossthewaterannularflow/entrainedaircoreinterfacetoallowcombineddischargeflowsandtheireffectonairentrainmenttobemodelled.ThepropagationofairpressuretransientsinbuildingdrainageandventsystemsisdefinedbytheStVenantequationsofcontinuityandmomentum[9],(1)(2)Thesequasi-linearhyperbolicpartialdifferentialequationsareamenabletofinitedifferencesolutiononcetransformedviatheMethodofCharacteristicsintofinitedifferencerelationships,Eqs.(3)–(6),thatlinkconditionsatanodeonetimestepinthefuturetocurrentconditionsatadjacentupstreamanddownstreamnodes,Fig.2.70 (18K)Fig. 2. StVenantequationsofcontinuityandmomentumallowairflowvelocityandwavespeedtobepredictedonanx-tgridasshown.Note,.FortheC+characteristic:(3)when(4)andtheC-characteristic:(5)when(6)wherethewavespeedcisgivenbyc=(γp/ρ)0.5.(7)Theseequationsinvolvetheairmeanflowvelocity,u,andthelocalwavespeed,c,duetotheinterdependenceofairpressureanddensity.Localpressureiscalculatedas(8)Suitableequationslinklocalpressuretoairflowortotheinterfaceoscillationoftrapseals,Table1.Table 1.Boundaryconditions70 OpenendexitSetplocal=atmSolvewithavailableC+Eq.(4)DeadendexitSetulocal=0.0SolvewithavailableC+Eq.(4)plocalpopenTreatasadeadendexitAirpathduetotrapdisplacementSetplocal=atmandsolvewithC+DepletedtrapSetplocal=atmandsolvewithC+PAPAexitBagatlinepressureVolume=0.0,p=linepressureBagfilling,p=atmSuminflowtodeterminebagvolumeBagpressurizesUsegasLawEquationwithbagvolumeandsolvewithC+todeterminebagpressureBaseofstack(entry)EmpiricalΔpvs.QwSolveempiricalrelationshipbetweenbackpressure,appliedwaterflowandentrainedairflowwithavailableC-Eq.(6)Sewerpressure(entry)BaseofstackImposesewerpressureandsolvewithC-Eq.(6)WindshearexitTopofstackImposevariableatmosphericpressureandsolvewithC+Eq.(4)Thecaseoftheappliancetrapsealisofparticularimportance.Thetrapsealwatercolumnoscillatesundertheactionoftheappliedpressuredifferentialbetweenthetransientsinthenetworkandtheroomairpressure.TheequationofmotionfortheU-bendtrapsealwatercolumnmaybewrittenatanytimeas(9)Itshouldberecognizedthatwhilethewatercolumnmayriseontheapplianceside,converselyonthesystemsideitcanneverexceedadatumleveldrawnatthebranchconnection.Inpracticaltermstrapsealsaresetat75or50 mmintheUKandotherinternationalstandardsdependentuponappliancetype.Trapsealretentionisthereforedefinedasadepthlessthantheinitialvalue.Manystandards,recognizingthetransientnatureoftrapseal70 depletionandtheopportunitythatexistsforre-chargeonappliancedischargeallow25%depletion.Theboundaryequationmayalsobedeterminedbylocalconditions:theAAVopeningandsubsequentlosscoefficientdependsonthelocallinepressureprediction.EmpiricaldataidentifiestheAAVopeningpressure,itslosscoefficientduringopeningandatthefullyopencondition.Appliancetrapsealoscillationistreatedasaboundaryconditiondependentonlocalpressure.Deflectionofthetrapsealtoallowanairpathto,orfrom,theapplianceordisplacementleadingtooscillationalonemaybothbemodelled.Reductionsintrapsealwatermassduringthetransientinteractionmustalsobeincluded.3.RoleofdiversityinsystemoperationIncomplexbuildingdrainagenetworkstheoperationofthesystemappliancestodischargewatertothenetwork,andhenceprovidetheconditionsnecessaryforairentrainmentandpressuretransientpropagation,isentirelyrandom.Notwosystemswillbeidenticalintermsoftheirusageatanytime.Thisdiversityofoperationimpliesthatinter-stackventingpathswillbeestablishediftheindividualstackswithinacomplexbuildingnetworkarethemselvesinterconnected.Itisproposedthatthisdiversityisutilizedtoprovideventingandtoallowseriousconsiderationtobegiventosealeddrainagesystems.Inordertofullyimplementasealedbuildingdrainageandventsystemitwouldbenecessaryforthenegativetransientstobealleviatedbydrawingairintothenetworkfromasecurespaceandnotfromtheexternalatmosphere.Thismaybeachievedbytheuseofairadmittancevalvesoratapredeterminedlocationwithinthebuilding,forexampleanaccessibleloftspace.Similarly,itwouldbenecessarytoattenuatepositiveairpressuretransientsbymeansofPAPAdevices.InitiallyitmightbeconsideredthatthiswouldbeproblematicaspositivepressurecouldbuildwithinthePAPAinstallationsandthereforenegatetheirabilitytoabsorbtransientairflows.ThismayagainbeavoidedbylinkingtheverticalstacksinacomplexbuildingandutilizingthediversityofuseinherentinbuildingdrainagesystemsasthiswillensurethatPAPApressuresarethemselvesalleviatedbyallowingtrappedairtoventthroughtheinterconnectedstackstothesewernetwork.70 Diversityalsoprotectstheproposedsealedsystemfromsewerdrivenoverpressureandpositivetransients.Acomplexbuildingwillbeinterconnectedtothemainsewernetworkviaanumberofconnectingsmallerboredrains.Adversepressureconditionswillbedistributedandthenetworkinterconnectionwillcontinuetoprovideventingroutes.Theseconceptswillbedemonstratedbyamulti-stacknetwork.4.Simulationoftheoperationofamulti-stacksealedbuildingdrainageandventsystemFig.3illustratesafour-stacknetwork.ThefourstacksarelinkedathighlevelbyamanifoldleadingtoaPAPAandAAVinstallation.WaterdownflowsinanystackgeneratenegativetransientsthatdeflatethePAPAandopentheAAVtoprovideanairflowintothenetworkandouttothesewersystem.PositivepressuregeneratedbyeitherstacksurchargeorsewertransientsareattenuatedbythePAPAandbythediversityofusethatallowsonestack-to-sewerroutetoactasareliefroutefortheotherstacks.(37K)Fig. 3. Fourstackbuildingdrainageandventsystemtodemonstratetheviabilityofasealedbuildingsystem.Thenetworkillustratedhasanoverallheightof12 m.Pressuretransientsgeneratedwithinthenetworkwillpropagateattheacousticvelocityinair.Thisimpliespipeperiods,fromstackbasetoPAPAofapproximately0.08 sandfromstackbasetostackbaseofapproximately0.15 s.Inordertosimplifytheoutputfromthesimulationnolocaltrapsealprotectionisincluded—forexamplethetrapscouldbefittedwitheitherorbothanAAVandPAPAasexamplesofactivecontrol.Traditionalnetworkswouldofcourseincludepassiveventingwhereseparateventstackswouldbeprovidedtoatmosphere,howeverasealedbuildingwoulddispensewiththisventingarrangement.Ideallythefoursewerconnectionsshownshouldbetoseparatecollectiondrainssothatdiversityinthesewernetworkalsoactstoaidsystemselfventing.Inacomplexbuildingthisrequirementwouldnotbearduousandwouldinallprobabilitybethenorm.Itisenvisagedthatthestackconnectionstothesewernetworkwouldbedistributedandwouldbetoabelow70 grounddrainagenetworkthatincreasedindiameterdownstream.Otherconnectionstothenetworkwouldinallprobabilitybefrombuildingsthatincludedthemoretraditionalopenventsystemdesignsothatafurtherlevelofdiversityisaddedtooffsetanydownstreamsewersurchargeeventsoflongduration.Similarconsiderationsledtothecurrentdesignguidancefordwellings.Itisstressedthatthenetworkillustratedisrepresentativeofcomplexbuildingdrainagenetworks.Thesimulationwillallowarangeofappliancedischargeandsewerimposedtransientconditionstobeinvestigated.Thefollowingappliancedischargesandimposedsewertransientsareconsidered:1.w.c.dischargetostacks1–3overaperiod1–6 sandaseparatew.c.dischargetostack4between2and7 s.2.Aminimumwaterflowineachstackcontinuesthroughoutthesimulation,setat0.1 l/s,torepresenttrailingwaterfollowingearliermultipleappliancedischarges.3.A1 sdurationstackbasesurchargeeventisassumedtooccurinstack1at2.5 s.4.Sequentialsewertransientsimposedatthebaseofeachstackinturnfor1.5 sfrom12to18 s.Thesimulationwilldemonstratetheefficacyofboththeconceptofactivesurgecontrolandinter-stackventinginenablingthesystemtobesealed,i.e.tohavenohighlevelroofpenetrationsandnoventstacksopentoatmosphereoutsidethebuildingenvelope.Theimposedwaterflowswithinthenetworkarebasedon‘real’systemvalues,beingrepresentativeofcurrentw.c.dischargecharacteristicsintermsofpeakflow,2 l/s,overallvolume,6 l,andduration,6 s.Thesewertransientsat30 mmwatergaugearerepresentativebutnotexcessive.Table2definesthew.c.dischargeandsewerpressureprofilesassumed.Table 2.w.c.dischargeandimposedsewerpressurecharacteristicsw.c.dischargecharacteristicImposedsewertransientatstackbaseTimeDischargeflowTimePressure70 Secondsl/sSecondsWatergauge(mm)Starttime0.0Starttime0.0+22.0+0.530.0+42.0+0.530.0+60.0+0.50.05.SimulationconventionsItshouldbenotedthatheightsforthesystemstacksaremeasuredpositiveupwardsfromthestackbaseineachcase.Thisimpliesthatentrainedairflowtowardsthestackbaseisnegative.AirflowenteringthenetworkfromanyAAVsinstalledwillthereforebeindicatedasnegative.Airflowexitingthenetworktothesewerconnectionwillbenegative.Airflowenteringthenetworkfromthesewerconnectionorinducedtoflowupanystackwillbepositive.Waterdownflowinaverticalishoweverregardedaspositive.Observingtheseconventionswillallowthefollowingsimulationtobebetterunderstood.6.WaterdischargetothenetworkTable2illustratesthew.c.dischargesdescribedabove,simultaneousfrom1 stostacks1–3andfrom2 stostack4.Abaseofstacksurchargeisassumedinstack1from2.5to3 s.AsaresultitwillbeseenfromFig.4thatentrainedairdownflowsareestablishedinpipes1,6and14asexpected.However,theentrainedairflowinpipe19isintothenetworkfromthesewer.Initially,asthereisonlyatricklewaterflowinpipe19,theentrainedairflowinpipe19duetothew.c.dischargesalreadybeingcarriedbypipes1,6and14,isreversed,i.e.upthestack,andcontributestotheentrainedairflowdemandinpipes1,6and14.TheAAVonpipe12alsocontributesbutinitiallythisisasmallproportionoftherequiredairflowandthe70 AAVfluttersinresponsetolocalpressureconditions.(58K)Fig. 4. Entrainedairflowsduringappliancedischarge.Followingthew.c.dischargetostack4thatestablishesawaterdownflowinpipe19from2 sonwards,thereversedairflowinitiallyestablisheddiminishesduetothetractionappliedbythefallingwaterfilminthatpipe.However,thesuctionpressuresdevelopedintheotherthreestacksstillresultsinacontinuingbutreducedreversedairflowinpipe19.Asthewaterdownflowinpipe19reachesitsmaximumvaluefrom3 sonwards,theAAVonpipe12opensfullyandanincreasedairflowfromthissourcemaybeidentified.Theflutterstageisreplacedbyafullyopenperiodfrom3.5to5.5 s.Fig.5illustratestheairpressureprofilefromthestackbaseinbothstacks1and4at2.5 sintothesimulation.Theairpressureinstack4demonstratesapressuregradientcompatiblewiththereversedairflowmentionedabove.Theairpressureprofileinstack1istypicalforastackcarryinganannularwaterdownflowanddemonstratestheestablishmentofapositivebackpressureduetothewatercurtainatthebaseofthestack.(40K)Fig. 5. Airpressureprofileinstacks1and4illustratingthepressuregradientdrivingthereversedairflowinpipe19.TheinitialcollapsedvolumeofthePAPAinstalledonpipe13was0.4 l,withafullyexpandedvolumeof40 l,howeverduetoitssmallinitialvolumeitmayberegardedascollapsedduringthisphaseofthesimulation.7.Surchargeatbaseofstack1Fig.6indicatesasurchargeatthebaseofstack1,pipe1from2.5to3 s.Theentrainedairflowinpipe1reducestozeroatthestackbaseandapressuretransientisgeneratedwithinthatstack,Fig.6.Theimpactofthistransientwillalsobeseenlaterinadiscussionofthetrap70 sealresponsesforthenetwork.(44K)Fig. 6. Airpressurelevelswithinthenetworkduringthew.c.dischargephaseofthesimulation.Notesurchargeatbasestack1,pipe1at2.5 s.Itwillalsobeseen,Fig.6,thatthepredictedpressureatthebaseofpipes1,6and14,intheabsenceofsurcharge,conformtothatnormallyexpected,namelyasmallpositivebackpressureastheentrainedairisforcedthroughthewatercurtainatthebaseofthestackandintothesewer.Inthecaseofstack4,pipe19,thereversedairflowdrawnintothestackdemonstratesapressuredropasittraversesthewatercurtainpresentatthatstackbase.Thesimulationallowstheairpressureprofilesupstack1tobemodelledduring,andfollowing,thesurchargeillustratedinFig.6.Fig.7(a)and(b)illustratetheairpressureprofilesinthestackfrom2.0to3.0 s,theincreasinganddecreasingphasesofthetransientpropagationbeingpresentedsequentially.ThetracesillustratethepropagationofthepositivetransientupthestackaswellasthepressureoscillationsderivedfromthereflectionofthetransientatthestackterminationattheAAV/PAPAjunctionattheupperendofpipe11.(73K)Fig. 7. (a)Sequentialairpressureprofilesinstack1duringinitialphaseofstackbasesurcharge.(b)Sequentialairpressureprofilesinstack1duringfinalphaseofstackbasesurcharge.8.SewerimposedtransientsTable2illustratestheimpositionofaseriesofsequentialsewertransientsatthebaseofeachstack.Fig.8demonstratesapatternthatindicatestheoperationofboththePAPAinstalledonpipe13andtheself-ventingprovidedbystackinterconnection.(57K)Fig. 8. Entrainedairflowsasaresultofsewerimposedpressuretransients.70 Asthepositivepressureisimposedatthebaseofpipe1at12 s,airflowisdrivenupstack1towardsthePAPAconnection.However,asthebaseoftheotherstackshavenotayethadpositivesewerpressurelevelsimposed,asecondaryairflowpathisestablisheddownwardstothesewerconnectionineachofstacks2–4,asshownbythenegativeairflowsinFig.8.AstheimposedtransientabatessothereversedflowreducesandthePAPAdischargesairtothenetwork,againdemonstratedbythesimulation,Fig.8.Thispatternrepeatsaseachofthestacksissubjectedtoasewertransient.Fig.9illustratestypicalairpressureprofilesinstacks1and2.Thepressuregradientinstack2confirmstheairflowdirectionupthestacktowardstheAAV/PAPAjunction.Itwillbeseenthatpressurecontinuestodecreasedownstack1untilitrecovers,pipes1and3,duetotheeffectofthecontinuingwaterflowinthosepipes.(38K)Fig. 9. Airpressureprofileinstack1and2duringthesewerimposedtransientinstack2,15 sintothesimulation.ThePAPAinstallationreactstothesewertransientsbyabsorbingairflow,Fig.10.ThePAPAwillexpanduntiltheaccumulatedairinflowreachesitsassumed40 lvolume.AtthatpointthePAPAwillpressurizeandwillassisttheairflowoutofthenetworkviathestacksunaffectedbytheimposedpositivesewertransient.Notethatasthesewertransientisappliedsequentiallyfromstacks1–4thispatternisrepeated.ThevolumeofthehighlevelPAPA,togetherwithanyothersintroducedintoamorecomplexnetwork,couldbeadaptedtoensurethatnosystempressurizationoccurred.(54K)Fig. 10. PAPAvolumeandAAVthroughflowduringsimulation.TheeffectofsequentialtransientsateachofthestacksisidentifiableasthePAPAvolumedecreasesbetweentransientsduetotheentrainedairflowmaintainedbytheresidualwaterflowsineachstack.70 9.TrapsealoscillationandretentionTheappliancetrapsconnectedtothenetworkmonitorandrespondtothelocalbranchairpressures.Themodelprovidesasimulationoftrapsealdeflection,aswellasfinalretention.Fig.11(a, b)presentthetrapsealoscillationsforonetraponeachofthestacks1and2,respectively.Astheairpressurefallsinthenetwork,thewatercolumninthetrapisdisplacedsothattheappliancesidewaterlevelfalls.However,thesystemsidelevelisgovernedbythelevelofthebranchentryconnectionsothatwaterislosttothenetwork.ThiseffectisillustratedinbothFig.11(a)and(b).Transientconditionsinthenetworkresultintrapsealoscillation,howeverattheendoftheeventthetrapsealwillhavelostwaterthatcanonlybereplenishedbythenextapplianceusage.Ifthetransienteffectsareseverethanthetrapmaybecometotallydepletedallowingapotentialcrosscontaminationroutefromthenetworktohabitablespace.Fig.11(a)and(b)illustratethetrapsealretentionattheendoftheimposednetworktransients.(114K)Fig. 11. (a)Trapsealoscillation,trap2.(b)Trapsealoscillation,trap7.Fig.11(a),representingthetraponpipe2,illustratestheexpectedinducedsiphonageoftrapsealwaterintothenetworkasthestackpressurefalls.Thesurchargeeventinstack1interruptsthisprocessat2 s.Thetraposcillationsabatefollowingthecessationofwaterdownflowinstack1.Theimpositionofasewertransientisapparentat12 sbythewatersurfacelevelrisingintheappliancesideofthetrap.Amoreseveretransientcouldhaveresultedin‘bubblingthrough’atthisstageifthetrapsystemsidewatersurfacelevelfelltothelowestpointoftheU-bend.Thetrapsealoscillationsfortrapsonpipes7,Fig.11(b)and15,areidenticaltoeachotheruntilthesequentialimpositionofsewertransientsat14and16 s.Notethatthesurchargeinpipe1doesnotaffectthesetrapsastheyareremotefromthebaseofstack1.Thetraponpipe20displaysaninitialreductioninpressureduetothedelayinappliedwaterdownflow.Thesewertransientinpipe19affectsthistrapataround18 s.70 Asaresultofthepressuretransientsarrivingateachtrapduringthesimulationtherewillbealossoftrapsealwater.Thisoveralleffectresultsineachtrapdisplayinganindividualwatersealretentionthatdependsentirelyontheusageofthenetwork.Trap2retains32 mmwatersealwhiletraps7and15retain33 mm.Trap20isreducedto26 mmwaterseal.Notethatthetrapsonpipes7and15wereexposedtothesamelevelsoftransientpressuredespitethetimedifferenceinarrivalofthesewertransients.Fig.11(a)and(b)illustratetheoscillationsofthetrapsealcolumnasaresultofthesolutionofthetrapsealboundarycondition,Eq.(10),withtheappropriateC+characteristic.Thisboundaryconditionsolutioncontinuallymonitorsthewaterlossfromthetrapandattheendoftheeventyieldsatrapsealretentionvalue.Intheexampleillustratedtheinitialtrapsealvaluesweretakenas50 mmofwater,commonforappliancessuchasw.c."sandsinks.10.Conclusion—viabilityofasealedbuildingdrainageandventsystemThesimulationpresentedconfirmsthatasealedbuildingdrainagesystemutilizingactivetransientcontrolwouldbeaviabledesignoption.Asealedbuildingdrainagesystemwouldofferthefollowingadvantages:•Systemsecuritywouldbeimmeasurablyenhancedasallhigh-levelopensystemterminationswouldberedundant.•Systemcomplexitywouldbereducedwhilesystempredictabilitywouldincrease.•Spaceandmaterialsavingswouldbeachievedwithintheconstructionphaseofanyinstallation.ThesebenefitswouldberealizedprovidedthatactivetransientcontrolandsuppressionwasincorporatedintothedesignintheformofbothAAVtosuppressnegativetransientsandvariablevolumecontainmentdevices(PAPA)tocontrolpositivetransients.Thediversityinherentintheoperationofbothbuildingdrainageandventsystemsandthesewersconnectedtothebuildinghavearoleinprovidinginterconnectedreliefpathsaspartofthesystemsolution.Themethodofcharacteristicsbasedfinitedifferencesimulationpresentedhasprovidedoutputconsistentwithexpectationsfortheoperationofthesealedsystemstudied.Theaccuracyofthesimulationinotherrecentapplications,includingtheaccuratecorroborationof70 theSARSspreadmechanismwithintheAmoyGardenscomplexinHongKongin2003,providesaconfidencelevelintheresultspresented.Duetotherandommodeofoperationofbuildingdrainageandventsystemsfurthersimulations,laboratoryandsiteinvestigationswillbeundertakentoensurethattheconceptiswhollyviable.70 密封的建筑排水系统和通气系统———活性气压的瞬变控制和抑制摘要由于通过成对的吸气阀和正压衰减器与管网中的立管互相连接的形式能控制和抑制活性气压瞬变，因此在综合楼中采用密封的建筑排水系统和通气系统被认为是一个可行的提议。文章通过四根立管提出一种模拟实验，说明了瞬时产生和加强的气压在排水管中的流动机制。这种模拟实验在水封不被破坏，系统压力得以维持的条件下，能够辨认活性气压控制设备的作用。系统安全性提高、可靠性增加且设施和材料费减少，可见这种最初结果是令人高度鼓舞的，且足以证实潜在的明确利益，但进一步的模拟实验有必要提供概念上的证明，且它与其他以检验为目的的实验室、可能的地方、试验相比是有利的。关键词：活性气压控制，存水弯保持，瞬变传播。命名原则C+-特征方程c波速,m/sD分支或堆积直径,mf摩擦因子，英国定义通过DarcyΔh=4fLu2/2Dg70 g重力加速度,m/s2K损失系数L管长,mp压力,N/m2t时间,su空气速度,m/sx距离,mγ比热率Δh水头损失,mΔp压力差,N/m2Δt时间间隔,sρ密度,kg/m3词尾A存水弯的应用B分支local70 中心条件T存水弯atm大气压力F摩擦R空间S存水弯系统w水目录命名原则1.介绍――瞬时气压的控制和抑制2.多立管建筑排水管网中的瞬时气压传播模拟实验的教学依据。3.系统运行差异的作用4.一个密封的多立管建筑排水个同时系统的郧西模拟实验5.模拟实验的规定6．排入管网的水7．立管1底部排水8．瞬时气压强加于污水管9．水封的振动和保持10.结论——密封建筑排水和通气系统的可行性1.介绍――瞬时气压的控制和抑制70 作为系统操作的自然结果，建筑排水系统和通气系统内部产生的气压瞬变对于水封破坏和交叉污染的可居住空间来说也是可靠的。[1]水封保护的传统模式，基于维多利亚女王时代的工程师对气味排除的观念[2]、[3]和[4]，通过交叉连接和立管排入大气[5]和[6]，主要取决于信任基础上的消极的解决方法。这种方法尽管既被证明了，也是传统的，但也有其内在弱点，如通气管末端较远[7]，导致了综合楼缓解反应到达较迟和敞开屋面立管末端内在的多样性。复杂的通气系统需要大量费用且于空间有密切联系[8]。在过去20年里，吸气阀（AAVs）的发展给设计师提供了一种缓解瞬时负压的方法，如在随机的洁具排水过程中，吸气阀有助于系统中水力条件的恢复。当吸气阀直接反映本地压力条件时，它们代表了一种控制活性气压的解决方法，它们自动打开，使新鲜空气进入管道系统，从而使系统的压力得到平衡并保护了冰封[9]。然而，吸气阀不能解决建筑排水系统和通气系统中瞬时正压传播的问题，污水管网中自由水流或远处产生的瞬时正压的到达通路间歇的关闭，有可能顺流进入一些其他的水——包括流入污水管的暴雨。正压衰减器[10]被开发用来吸收瞬时正压产生的气流，这种衰减器完成了必要的设备供应，为剧烈的瞬时气压的控制和抑制被采用到建筑排水系统和通气系统中做准备，这些建筑既包括一般性建筑也包括那些需特殊考虑的多种屋面、立管末端未封密的建筑。正压衰减器由大量可变量组成，这些可变量在瞬时正压的影响下不断扩充，从而为气流不断衰减做准备，因此产生的瞬时正压强度降低。吸气阀和正压衰减器设备共同使用被作为一个完全密封的建筑排水系统和通风系统的考虑因素。图1说明了吸气阀和正压衰减器设备，注意在负压条件下无水存水弯充当吸气阀。(39K)图1:剧烈的瞬时气压控制设备控制正压和负压剧烈的瞬时气压的控制和抑制考虑到为保护水封对正压和负压偏移的局部调节。这种方法与传统的消极方法相比有明显的优点。它节约了等待瞬时气压从通气管排入大气使环节反映恢复的时间，避免了在瞬时气压传播过程中对其他系统中水封的瞬时影响。2.多立管建筑排水管网中的瞬时气压传播模拟实验的教学依据。建筑排水和通气系统中瞬时气压的传播是可以理解和解决的问题，它可以通过StVenant70 方程式定义的非稳定流的连续性方程和动力方程来理解，可以通过有限的各种图表、利用特征方程的方法来解决。通气立管系统中下落的环形水和系统范围内的瞬时气压的反射和传播，包括未密封的通气管末端、污水管接头处、水封装置及AAV、PAPA控制装置都能带走空气，基于以上结果，系统中瞬时气压的产生和传播可以被准确模拟。这种模拟实验[11]提供当地的气压、速度和光速数据，贯穿管网中的时间和距离间隔很小，仅为0.001s和300mm。另外，模拟实验模拟当地水封装置的振动和气压控制装置的运用，从而依据管网中气流生成数据并能识别系统的不足及可能导致的后果。当这一模拟实验已经完全生效时，它单独的证实了2003年厦门花园内SARS病毒的传播机理。这更进一步的证实了它的预言[12]。瞬时气压的传播依赖于系统条件的变化速率。大量的环形溢流管导致了排除气流的提高和系统压力的降低。排出气流的延迟导致瞬时正压产生。管网中外部水的进入同样也能传播瞬时正压和瞬时负压。有水立管中的环形水流带走一股气流，这是由于在环形水和空气核心表面之间建立的“无滑”条件和沿立管往下产生的预期的压力变化。由于空气经过排水分支结合点处形成的水幕时产生摩擦和影响，在立管入口上端气压低于大气压。在低湿度立管中，由于优先对气流施加牵引力，气压穿过立管底部的水幕，从而气压高于大气压。模拟非稳定流所采用的特征方法的价值在20世纪60年代第一次被正式承认[13]，杰克[14]这一关系进行定义，采用模拟实验模拟施加于排出气体的牵引力量。大量的实验数据允许对“伪摩擦因素”定义，这些因素适合在湿立管中应用，并能作用于环形水流空气排除核心界面，从而允许进行混合排出流，及其对排除空气影响的模拟。建筑排水系统和通气系统中的瞬时气压的传播是由StVenant的连续性方程和动力方程定义的。(1)(2)有限的解一旦通过特征方程转化为有限的各种关系式、方程式，这些半双曲线性的偏微分方程是经得起检验的。⑶－⑹，未来一个时间段结点处的连接条件至上、下段临近节点的现行条件，图2。(18K)图2：StVenant70 连续性方程和动力方程预计将气流速度和波速用X-T坐标表示出来.注：⊿x<1.0m，⊿t<0.003s当(4)时为C+特征：(3)当(6)时为C-特征：(5)波速C可用公式c=(γp/ρ)0.5.(7)求得。由于气压和密度的相互依赖，这些方程式与空气流速U和本地波速C有直接关系。本地压力可用下式计算(8)合适的方程式将气流或水封振动分界面与本地气压相关，见表1表1限制条件OpenendexitSetplocal=atmSolvewithavailableC+Eq.(4)DeadendexitSetulocal=0.0SolvewithavailableC+Eq.(4)AAVexitplocal>popenTreatasadeadendexitplocal