管道死角盲管规则

1、6d、3d、2d、1.5d管道死角/盲管规则，以及零死角阀门介绍6d、3d、2d、1.5d管道死角/盲管规则以及零死角阀门介绍关于管道死角/盲管的定义和要求，不同法规和指南有不同的要求，这些要求如下：1、1976 cfr 212规范为6d，指主管道中心到支管阀门中心的距离应小于支管直径的6倍。2、1993 美国高纯水检查指南为6d，指主管道中心到支管阀门密封点的长度应小于支管直径的6倍。3、2001 ispe水和蒸汽基准指南为3d，指主管外壁到支管阀门密封点的长度应小于支管直径的3倍。4、2009 asme bpe为2d，指主管内壁到阀门密封点的长度应小于支管直径的2倍。5、who 建议为1.

2、5d，应避免大于分支管径1.5倍的盲管。6、2010版中国gmp指南：为了避免将来造成混乱,本指南建议死角长度从管的外壁来考虑。我们建议避免对于最大可允许的死角做硬性规定。最后,在不考虑死角长度的情况下,水质必须满足要求。工程设计规范要求死角长度最小,有很多好的仪表和阀门的设计是尽量减少死角的。我们应该认识到如果不经常冲洗或消毒,任何系统都能会存在死角。各种规定和提法甚至测量的方法不尽相同， 但是目前的所有提法都不是“法规”而是工程的建议和标准。thetruth about the 3d/6d rule3d/6d规则的真相the installation of pipework leads t

3、o recurrent discussions about how deadlegs can be prevented and about the maximum length outgoing pipes/pipe tees mayhave for the sensor. there is less throughflow in dead legs. hence, it isharder to clean them and during thermal sanitisation it takes longer until these"branches" have also

4、 reached the required temperature. in calls fortender and tests the 3d/6d rule is often used for the specification, but notalways in the completely correct way. in order to further explain this, pleaseread following the history of this rule.管道的安装一再引起关于如何防止死管的讨论，以及探头安装位置连出的支管最大长度问题的讨论。在死管中水流较少，因此很难对其

5、进行清洁，并且在高温消毒中会需要很长时间使得这些“支管”也能达到所需的温度。在设计和测试中，3d/6d规则通常用作标准，但并不总是用的完全正确。为了进一步解释这个问题，请阅读以下关于此规则的历史。the rule for the prevention of dead legs (in a wfi system) is mentionedfor the first time in the draft of the fda guides for large volumeparenterals (lvp), 21 cfr 212.49 in 1972. this requirement was ta

6、ken up inthe fda guide to inspections of high purity water systems in 1993 - onlynow it was called 6d rule. this document is still used by fda inspectors asguidance for gmp inspections. in 2001 the dead leg rule reappeared in an ispeguide. the ispe baseline guide water and steam now talks

7、about the 3drule. further statements can be found in who trs 929 (1,5 d), who trs 970 (3d)and in asme bpe-2009 (2d). this is a standard of the american society ofmechanical engineers for bioprocessing equipment. this means:防止盲管的规则（在注射用水系统中）首次是1972年在美国fda大容量注射剂（lvp）指南草案，21 cfr 212.49中提到的。这个要求在1993年被放

8、进了fda高纯水系统检查指南中-现在我们叫它为6d规则。该文件到现在还被fda检查员用作 gmp检查指南。在2001年，盲管规则在ispe指南中出现。ispe基准指南“水和蒸汽”现在讲的是3d规则。在who trs929（1.5d）中、who trs970(3d)和asme bpe-2009(2d)有进一步的说明。这是美国生物工艺设备机械工程协会的标准。它表示： there is a 1.5d, a 2d, a 3d as well as a 6d rule.有1.5d，2d，3d以及6d规则the rule has been described for hot storage water s

9、ystems but it is also used for all cleaning in place systems (cip).规则描述的是热水存贮系统，但也适用于所有在线清洁系统（cip）a rule of thumb became the industry standard.这种经验性的法则已成为行业标准。but how does it work in practice? is one rule more binding or better thanthe others?但在实践中要怎么应用呢？是否有一个规则比其它的更具有法规效力呢？one has to know that the

10、3d and the 6d rule cannot be compared directlybecause they have a different reference point. in the case of the 3d rule thelength l of the dead leg is measured from the pipe wall of the main pipe andput in relation to the diameter of the parting pipe. the initial 6d rulemeasures the length l beginni

11、ng in the centre of the main pipe.我们必须知道3d和6d规则并不能直接进行比较，因为它们有不同的测量点。采用3d规则时，死管的长度是从主管的管壁开始测量的，与支管的直径进行比较；而6d规则是从主管的中心线开始测量的。as a rule the "3d or shorter" has proven itself for watersystems and is said to be state of the art. but the following is also valid:the higher the risk or the value

12、 of the product the shorter. today 1.5 d isstate of the art in the case of biotechnology applications. but this may also mean that a piece of pipe in an older clean steam system may remain 6d withoutposing a gmp risk.作为一个规则，“3d或更短”已经证明了自己对水系统是有用的，并被认为是理想的设计。但以下理论也是有效的：风险越高或产品附加值越高，设计死管更短。今天，1.5d在生物制品应用中已是理想的设计。但这也表示一个旧的洁净蒸汽系统的一支管道仍可以维持其6d长度，而并没有gmp风险。零死角阀门现在，零死角阀门（0d 阀门）已有生产，当然成本会更高一些。各个厂商所设计的零死角阀门可能会有点不一样。下图是一种类型的零死角阀门，红色线为主管流向，粉色线为支管流向，阀门密封点直接在主管管壁上(即l=0d)。这种阀门的内部结构如下