ECA新闻20150527：3D/6D规则的真相 （精彩）

ECA新闻20150527：3D/6D规则的真相 （精彩）

2015-05-27 22:53:53

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ECA新闻

GMP News
27/05/2015

The Truth about the 3D/6D Rule

3D/6D规则的真相

The installation of pipework leads to recurrent discussions about how dead legs can be prevented and about the maximum length outgoing pipes/pipe tees may have for the sensor. There is less throughflow in dead legs. Hence, it is harder to clean them and during thermal sanitisation it takes longer until these "branches" have also reached the required temperature. In calls for tender and tests the 3D/6D rule is often used for the specification, but not always in the completely correct way. In order to further explain this, please read 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 mentioned for the first time in the draft of the FDA Guides for Large Volume Parenterals (LVP), 21 CFR 212.49 in 1972. This requirement was taken up in the FDA Guide to Inspections of high purity water systems in 1993 - only now it was called 6D rule. This document is still used by FDA inspectors as guidance for GMP inspections. In 2001 the dead leg rule reappeared in an ISPE guide. The ISPE Baseline Guide Water and Steam now talks about the 3D rule. 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 of Mechanical Engineers for BioProcessing Equipment. This means:

防止死管的规则（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，死管规则在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 systems 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.
• 姆指规则已成为行业标准
  

But how does it work in practice? Is one rule more binding or better than the others?
One has to know that the 3D and the 6D rule cannot be compared directly because they have a different reference point. In the case of the 3D rule the length L of the dead leg is measured from the pipe wall of the main pipe and put in relation to the diameter of the parting pipe. The initial 6D rule measures the length L beginning in the centre of the main pipe.

但在实践中要怎么应用呢？一个规则是否比其它的更具有法规效力呢？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 water systems and is said to be state of the art. But the following is also valid: The higher the risk or the value of the product the shorter. Today 1.5 D is state 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 without posing 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清洁蒸汽系统的一支管道仍可以维持其

6D

长度，但并没有

GMP

风险。

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感谢分享！！！！！！但是如何执行

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