风速指导值：0.36-0.54 相关说明

渐雨听风

看见另外一个帖子在说这个，然后分享一下之前找到的一个资料。
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渐雨听风

CLEANROOM AIRFLOW VELOCITIES
Air is of fundamental importance to cleanrooms, either as a contamination source (microorganisms carried in the air-stream) or as a control measure to minimize contamination (through the supply of clean air and controlling the direction of air movement). Therefore, controlling a cleanroom requires careful attention to the factors of air filtration, air velocity and air flow. While cleanrooms are typically designed to achieve turbulent airflow, with clean air devices, and EU / WHO GMP Grade A / ISO 14644 class 5 areas, the air is designed to be unidirectional whereby the air direction and air velocity are designed to remove any contamination deposited into the air-stream away from the critical area. These devices contain HEPA filters, which control the air-speed and direction.
空气对洁净室至关重要，无论是作为污染源（气流中携带的微生物）还是作为控制措施（通过供应洁净空气和控制空气运动方向）来减少污染。因此，控制洁净室需要仔细注意空气过滤、空气速度和空气流量等因素。虽然洁净室通常设计为实现湍流气流，洁净空气装置和EU / WHO GMP等级A / ISO 14644 5级区域，空气被设计为单向的，其中空气方向和空气速度被设计为去除任何污染沉积到远离关键区域的气流中。这些设备包含高效微粒空气过滤器，控制空气的速度和方向。

Unidirectional flow and be defined as an airflow moving in a single direction, in a robust and uniform manner, and at sufficient speed to sweep particles away from the critical processing or testing area with regularity. Hence the object of the unidirectional airflow is to push outward any contamination which might be deposited into the air-stream and to avoid the potential for contamination dropping out of the air, either though gravity or by striking a object, and falling onto a critical surface.
单向流的定义是沿单一方向，以强劲和均匀的方式，以足够的速度有规律地将颗粒从关键加工或测试区域扫走的气流。因此，单向气流的目的是将任何可能沉积在气流中的污染物向外推，并避免污染物通过重力或撞击物体而从空气中脱落并落在临界表面上的可能性。

Part of the control of air rests with air direction and this is a factor of airflow velocity. Poor airflow uniformity leads to turbulent airflow and vortex formation. In terms of the velocity of the air, this is described in some regulatory documents: 0,.45 meters per second within arrange of 20%. Whether achieving good airflow (and thereby avoiding poor airflow) needs to conform to the range specified in regulatory guidance documents has been a long-standing issue, particularly given the non-scientific origins of the regulatory guidance values. This article considers regulatory guidance on airflow velocities and the way that these are verified, and whether satisfactory airflow can be achieved outside of these guidance values. The discussion extends to consideration of the verification of these parameters at working height, especially in light of if this the most appropriate location by which to measure air velocities.
空气的控制部分取决于空气的方向，这是气流速度的一个因素。气流均匀性差导致气流紊流，形成涡旋。就空气的速度而言，在一些规范性文件中有描述：0，。45米每秒在20%的范围内。实现良好气流（从而避免不良气流）是否需要符合监管指导文件中规定的范围一直是一个长期存在的问题，特别是考虑到监管指导值的非科学来源。本文考虑了对气流速度的调节指导及其验证方式，以及在这些指导值之外是否可以获得满意的气流。讨论扩展到考虑在工作高度验证这些参数，特别是考虑到这是否是测量空气速度的最适当位置。
Unidirectional Airflow and a Short History of Air Velocities

Unidirectional airflow is obtained through High Efficiency Particulate Air (HEPA) filters. HEPA filters function through a combination of three important aspects. With this, there are one or more outer filters that work like sieves to stop the larger particles of dirt, dust, and hair. Inside those filters, there is a concertina - a mat of very dense fibres - which traps smaller particles. The inner part of the HEPA filter catch particles as they pass through in the moving air stream. There are different grades of HEPA filters based on their ‘efficiency ratings (1).
单向气流通过高效微粒空气（HEPA）过滤器获得。HEPA过滤器通过三个重要方面的组合发挥作用。有了这个，有一个或多个外部过滤器，像筛子一样工作，以阻止较大的污垢，灰尘和头发颗粒。在这些过滤器内部，有一个手风琴——一层非常致密的纤维——可以捕获更小的颗粒。高效微粒微粒过滤器的内部部分，当他们通过移动的气流捕获颗粒。HEPA过滤器根据其效率等级(1)有不同的等级。

The concept of laminar airflow (what is now described today as ‘unidirectional airflow’) was introduced with the first industrial cleanrooms and clean spaces of the 1960s. It was noted that when air is introduced into the cleanroom at a high velocity which causes the air to travel along a unidirectional path over a required distance. In doing so, contamination is swept away from the critical area unlike the more random distribution and transition of contaminants in turbulent flow cleanrooms (2).
层流气流的概念（现在被描述为“单向气流”）是在20世纪60年代第一个工业洁净室和洁净空间中引入的。值得注意的是，当空气以高速进入洁净室时，会使空气沿单向路径行进所需的距离。在这样做的过程中，污染物被从临界区域冲走，而不像湍流洁净室中污染物的随机分布和转移(2)。

The development of laminar flow technology was completed in 1961 by a team led by Willis Whitfield at the Sandia Corporation (later the Sandia National Laboratories) based at Albuquerque, New Mexico, USA, in partnership with the U.S. Atomic Energy Commission (3). This concept of laminar airflow led to the development of specialised airflow cabinets whereby greater levels of cleanliness could be achieved through air passing at a sufficient velocity. It was this work that showed that an airflow velocity of 90 feet per minute was adequate to achieve the necessary levels of particle cleanliness (avoiding settling particles of a diameter of 5.0 µm and greater) whilst maintaining unidirectional flow. This velocity also fitted with the capabilities of the fans in use at the time in relation to noise reduction. While this was effective, a fuller range – such as 25 to 250 feet per minute – was not explored (4). While the range of 90 feet per minute suited the Sandia Corporation conditions, this velocity part of the first U.S. cleanroom standard - Federal Standard 209 in 1963 (a forerunner to the ISO 14644 cleanroom standard). 90 feet per minute ±20 feet per minute (which, when metricised becomes 0.45 metres per second) also became adopted by regulatory authorities, when the FDA adopted the FS 209 document. The velocity also became part of EU GMP. At no stage was this velocity reconsidered to determine what the most applicable range was based on science, or even whether it was necessary to state a range at all.
层流技术的发展于1961年由位于美国新墨西哥州阿尔伯克基的桑迪亚公司（后来的桑迪亚国家实验室）的Willis Whitfield领导的团队与美国原子能委员会合作完成(3)。层流气流的概念导致了专门的气流柜的发展，通过空气以足够的速度通过，可以实现更高水平的清洁度。正是这项工作表明，90英尺/分钟的气流速度足以达到必要的颗粒清洁度水平（避免直径为5.0 &#181；m及更大的颗粒沉降），同时保持单向流动。这个速度也符合当时使用的风扇在减少噪音方面的能力。虽然这是有效的，但更大的范围（如25至250英尺/分钟）没有被探索(4)。虽然90英尺/分钟的范围适合桑迪亚公司的条件，但这个速度是美国第一个洁净室标准的一部分- 1963年的联邦标准209 （ISO 14644洁净室标准的前身）。当FDA采用FS 209文件时，监管机构也采用了90英尺/分钟±20英尺/分钟（当公制化为0.45米/秒时）。流速也成为欧盟GMP的一部分。在任何阶段，都没有重新考虑这个速度，以确定科学上最适用的范围是什么，或者甚至是否有必要陈述一个范围。

The inclusion of 90 feet per minute in the first iteration of FS 209 came with the explanatory text that the velocity was “not mandatory”. With the first revision – FS 290A in 1966 – the text “individual circumstances may dictate other values” was added. The 1973 version changes the range from 90 feet per minute ±20 feet per minute to 90 feet per minute ±20% (72 -108 feet per minute) but continued with explanatory text indicating that other values could be considered. In 1987 the first U.S. FDA guidance for aseptic processing adopted the 90 feet per minute ±20% air velocity requirement, although in the same year the FS 209C standard dropped mention of any specific velocity completely, placing the emphasis upon air visualization (5).
在FS 209的第一次迭代中包含了90英尺/分钟，并附有解释性文字，说明速度“不是强制性的”。第一次修订- 1966年的FS 290A -增加了“个别情况可能决定其他值”的案文。1973年的版本将范围从90英尺/分钟±20英尺/分钟更改为90英尺/分钟±20%（72 -108英尺/分钟），但继续使用解释性文本表明可以考虑其他值。1987年，第一个美国FDA无菌处理指南采用了90英尺/分钟±20%的空气速度要求，尽管同年FS 209C标准完全放弃了任何特定速度的提及，将重点放在空气可视化上(5)。

Current Airflow Velocities Guidance

Regulatory standards for cleanroom unidirectional airflow velocities differ in terms of where measurements are to be taken from and in terms of how much weight should be placed upon specific velocities. In terms of position, the U.S. FDA guidance, the requirement is to measure airflow velocities below the filter face at a distance of 6 inches (6). Similarly, to meet ISO 14644 measurements of the airflow velocity should be at approximately 150 mm to 300 mm from the filter face (7). However, under EU (and WHO) GMP, the requirement is to measure airflows at working height, with working height to be defined by the user. The velocity is assessed using an anemometer, a device for measuring wind speed. There are two common designs – vane and hot wire. The typical testing frequency is six-monthly or following any maintenance work or filter changes (8).
洁净室单向气流速度的监管标准在测量位置和特定速度上应该放置多少重量方面有所不同。在位置方面，美国FDA指南的要求是测量过滤器表面下方距离6英寸的气流速度(6)。同样，为了满足ISO 14644，风速的测量应在距离过滤器表面约150 mm至300 mm处(7)。然而，在EU（和WHO） GMP中，要求是测量工作高度的气流，工作高度由用户定义。风速是用风速计来评估的，这是一种测量风速的装置。有两种常见的设计-叶片式和热丝式。典型的测试频率是六个月或在任何维护工作或过滤器更换之后(8)。

Neither EU GMP or FDA provide any recommendations about the number of readings to take. According ISO 14644-3:2005 the number of measuring points should be sufficient to determine the supply airflow rate in cleanrooms and clean zones. This should be the square root of 10 times of area in square meters. However, not less than 4 readings should be taken. At least one point per filter should be measured.
欧盟GMP或FDA都没有提供任何关于读数数量的建议。根据ISO 14644-3:2005，测量点的数量应足以确定洁净室和洁净区的送风速率。这应该是√10乘以面积，单位是平方米。但是，读数不应少于4次。每个滤波器至少要测量一个点。

In each case, the airflow velocity range is recommended to be in the range 0.45 metres per second, ±20% (that is 0.36 to 0.45 ms-1). EU GMP Annex 1, for example states that “Laminar air flow systems should provide a homogeneous air speed in a range of 0.36 to 0.54 m/s (guidance value) at the working position in open clean room applications” (9). However, more flexibility is provided with the FDA 2004 guidance which states: “at a velocity sufficient to sweep particles away from the filling / closing operation and maintain unidirectional airflow during operation.”
在每种情况下，风速范围建议为0.45 m / s±20%（即0.36 ~ 0.45 ms-1）。例如，EU GMP附录1规定，“层流气流系统应在开放式洁净室应用的工作位置提供0.36至0.54 m/s（指导值）的均匀空气速度”(9)。然而，FDA 2004指南提供了更多的灵活性，该指南规定：“速度足以将颗粒从填充/关闭操作中扫走，并在操作期间保持单向气流。”

The 2004 guidance further states, via a footnote to the main text: “A velocity from 90 feet per minute is generally established, with a range of ±20% around the set point. Higher velocities may be appropriate in operations generating high levels of particulates.”
2004年的指南在正文的脚注中进一步指出：“通常设定的速度为每分钟90英尺，设定值周围的范围为±20%。在产生高水平微粒的作业中，更高的速度可能是合适的。”

The air velocity range quoted in the regulatory documents is stated to be a “guidance value”, inferring that higher or slower air velocities could be used provided there is sufficient justification. In theory, the risk from lower air velocities is from insufficient laminarity and an inability of the air velocity to effectively sweep away any particles in the air-stream. The risk arising from faster airflow velocities is from turbulence, and a tendency for the air to potentially eddy. However, do the standards really seek to imply that, say, going to 0.45 ±30% would present a contamination risk? If they do, then this is not based on sound science.
监管文件中引用的空气速度范围被称为“指导值”，这意味着在有充分理由的情况下，可以使用更高或更慢的空气速度。从理论上讲，较低的空气速度的风险是由于层流不足和空气速度无法有效地扫走气流中的任何颗粒。更快的气流速度带来的风险来自于湍流，以及空气潜在的涡流趋势。然而，标准是否真的试图暗示，比如说，达到0.45±30%就会有污染风险？如果他们这样做，那么这不是基于可靠的科学。

While the air velocities remain guidance, experience suggests that some regulators are more open to considering velocities outside of these ranges than others. Furthermore, it is often the case that lower airflows can provide the same level of particle control and unidirectional pattern; and sometimes faster airflows are required, either as a result of equipment balancing or due to remove particles from certain operations (such as where powder is handled). In such cases satisfactory air patterns can be demonstrated through airflow visualisation. This is why, in this author’s opinion, the airflow velocities should be removed from future updates, and placed with individual user assessments based on air pattern visualisation and particle counting. Consideration of this is discussed next.
虽然空气速度仍然是指导，但经验表明，一些监管机构比其他监管机构更愿意考虑超出这些范围的速度。此外，通常情况下，较低的气流可以提供相同水平的颗粒控制和单向模式；有时，由于设备平衡或由于从某些操作（如处理粉末的地方）去除颗粒，需要更快的气流。在这种情况下，可以通过气流可视化显示令人满意的空气模式。这就是为什么，在笔者看来，气流速度应该从未来的更新中删除，而放在基于空气模式可视化和粒子计数的个人用户评估中。下面将讨论对这一点的考虑。

Why Consider Alternative Airflow Velocities?

As indicated above, an airflow velocity of 0.45 meters/second (90 feet per minute), with a range of plus or minus 20 percent around the setpoint, has been established, albeit open to different degrees of interpretation, since the 1960s and it has formed regulatory guidance since the mid-1980s. There has been regulatory drift towards seeing these airflow velocities are mandatory. This is a mistake, since lower velocities, requiring lower energy use, may achieve the same effect; and higher velocities may be appropriate in operations generating high levels of particulates.
如上所述，自20世纪60年代以来，已经建立了0.45米/秒（90英尺/分钟）的气流速度，在设定值周围的正负20%的范围内，尽管有不同程度的解释，但自20世纪80年代中期以来已经形成了监管指导。监管机构倾向于认为这些气流速度是强制性的。这是一个错误，因为更低的速度，需要更少的能量消耗，可能会达到同样的效果；在产生高水平颗粒物的操作中，更高的速度可能是合适的。

What should be stipulated instead is where air velocity becomes related to performance expectations where the air in critical areas is supplied, via point of use as HEPA- filters, in a unidirectional manner and at a velocity sufficient to sweep particles away from the critical area during operations, irrespective of the velocity setting. This means setting air velocity parameters for each processing line or item of equipment and ensuring these are justified and appropriate to maintain air quality under dynamic conditions within a defined space.
应该规定的是,空气速度与性能预期有关,在关键区域内,空气在关键区域内,通过作为HEPA -过滤器的程度,以一种单向的方式,在速度上,足以将粒子从临界区域中清除,而不考虑速度设置。这意味着为每一个加工线或设备的物品设定空气速度参数,确保这些是正当的,并适当地在一个明确的空间内保持空气质量。



Literature also supports this position. Work by Whyte, which looked at airflow velocities covering the range of 0.1 m/s to 0.6 m/s showed that airflow velocities below 0.3 m/s were insufficient to provide stable unidirectional airflow and for achieving the required low levels of particle and bacterial concentrations. Increasing the airflow velocity up to 0.6 m/s gave low airborne counter, although this was on the basis of a ‘law of diminished returns’ in that the amount of additional energy expended did not alter the particle levels significantly. The assessment suggested that an airflow velocity of 0.3 m/s was optimal (10).
文献也支持这一观点。怀特研究了0.1米/秒到0.6米/秒的气流速度，结果表明，低于0.3米/秒的气流速度不足以提供稳定的单向气流，也不足以达到所需的低颗粒和细菌浓度水平。将气流速度提高到0.6 m/s会产生较低的空气阻力，尽管这是基于“收益递减定律”，即额外消耗的能量并没有显著改变颗粒水平。评估表明，0.3 m/s的气流速度是最佳的（10）。

Where alternate airflow velocities are proposed, these can be assessed through the recording of particle counts and by airflow visualisation studies. The revised text to EU GMP Annex 1 (not in force at the time of writing but profiled in a recent edition of the Journal of GxP Compliance) (11) puts greater emphasis upon airflow movement than with air velocity:
当提出交替气流速度时，可以通过记录颗粒计数和气流可视化研究来评估这些速度。EU GMP附录1的修订文本（在撰写本文时尚未生效，但在GxP合规期刊的最新版本中进行了介绍）（11）更加强调气流运动而不是空气速度：

“Grade A: The local zone for high risk operations, e.g. filling zone, stopper bowls, open ampoules and vials, making aseptic connections. Normally, such conditions are provided by a localised air flow protection, such as laminar air flow work stations or isolators.”
“A级：高风险操作的局部区域，例如灌装区，塞碗，打开安瓿和小瓶，进行无菌连接。通常，这种情况由局部气流保护装置提供，例如层流气流工作站或隔离器。”

The reference to ‘laminar airflow’ is confusing and outdated. Moreover, the inference that isolators require the same air velocities as to other Grade A devices is out of step with most studies (such as Peters et al (12) and Midcalf et al (13)). The draft goes on to read:
“层流”的说法既令人困惑又过时。此外，隔离器需要与其他A级装置相同的空气速度的推断与大多数研究（如Peters等人（12）和Midcalf等人（13））不一致。草案接着写道：

“Unidirectional air flow systems should provide a homogeneous air speed in a range of 0.36 - 0.54 m/s (guidance value), the point at which the air speed measurement is taken should be clearly justified in the protocol. During initial qualification and requalification air speeds may be measured either close to the terminal air filter face or at the working height, Where ever the measurement is taken it is important to note that the key objective is to ensure that air visualization studies should correlate with the airspeed measurement to demonstrate air movement that supports protection of the product and open components with unidirectional air at the working height, where high risk operations and product and components are exposed. The maintenance of unidirectional airflow should be demonstrated and validated across the whole of the grade A area. Entry into the grade A area by operators should be minimized by facility, process and procedural design.”
“单向气流系统应在0.36 - 0.54 m/s（指导值）范围内提供均匀的空气速度，空气速度测量的点应在协议中明确说明。在初始鉴定和再鉴定过程中，可以在靠近终端空气过滤器表面或工作高度处测量空气速度，无论在何处进行测量，都必须注意，关键目标是确保空气可视化研究应与空速测量相关联，以证明空气运动支持保护产品和工作高度的单向空气打开组件。高风险操作、产品和部件暴露的地方。维持单向气流应在整个A级区域进行演示和验证。应通过设施、工艺和程序设计尽量减少操作人员进入A级区域。”

Despite this the draft guidance does not go as far to remove the ‘guidance’ airflow velocity values of 0.45 meters per second ±20%.  However, it is suggested in this paper that airflow visualisation studies can provide the means to consider alternate airflow velocities. This approach recognises actual performance, in the operational state with equipment running and person el carrying out the necessary activities, ahead of velocity.
尽管如此，草案指导并没有走得太远，以消除“指导”气流速度值0.45米每秒±20%。然而，本文建议气流可视化研究可以提供考虑交替气流速度的手段。这种方法在设备运行和人员执行必要活动的操作状态下，提前识别实际性能。

Airflow Visualisation Studies

The purpose of flow visualization is to confirm the smoothness, flow patterns and other spatial and temporal characteristics of airflow in an installation. For this, the airflow is examined through airflow visualisation mapping whereby smoke is generated, and the behaviour of the smoke is studied and then captured by a video camera. Air-flow studies can demonstrate a significant amount of information. This can relate to contamination control in assessing whether air-flows are drawing potentially contaminated air towards a critical zone of whether certain objects in the air-stream cause contamination by forcing the air to change direction (14).
流动可视化的目的是确认装置中气流的平滑度、流动模式和其他时空特征。为此，通过气流可视化映射来检查气流，从而产生烟雾，并研究烟雾的行为，然后由摄像机捕获。气流研究可以证明大量的信息。这可以与污染控制有关，评估气流是否将潜在污染的空气吸引到一个关键区域，以及气流中的某些物体是否通过迫使空气改变方向而导致污染（14）。

To measure the aerodynamic performance of the unidirectional airflow unit, smoke should be introduced at the filter face so that the distribution of the smoke downwards and away from the critical zone can be seen. Smoke should also be introduced at the working height, immediately above the area where product or product components are exposed. The assessment should note the impact of the machine upon the airflow. Does the smoke, for example, entrails inwards when the air impacts upon the filling machine guarding? What is the effect of disturbances caused by the motion of machine operations? The biggest risk will be when potential airborne particles accumulate in vortex regions.  When a unidirectional air flow strikes and object, an obstacle will create a 'wake region'.  Such regions should be studied for vortices and potential particle accumulation (15).
为了测量单向气流单元的气动性能，应该在过滤器表面引入烟雾，这样可以看到烟雾向下和远离临界区域的分布。也应在工作高度，即产品或产品部件暴露区域的正上方引入烟雾。评估时应注意机器对气流的影响。例如，当空气冲击灌装机防护装置时，烟雾是否向内扩散？由机器操作引起的扰动的影响是什么？最大的风险将是潜在的空气颗粒在涡旋区域积聚。当单向气流撞击物体时，障碍物会形成一个“尾流区”。应该研究这些区域的涡旋和潜在的颗粒积聚（15）。

Any regions of stagnation should be detected.  When unidirectional air flow meets an object, wakes and vortex streets can be formed.  This causes turbulence.  This can lead to pockets of stagnation in front of machinery and work surfaces that are perpendicular to the main direction of the air flow.  Such pockets can be unpredictable in speed and direction and require mapping. Another potential risk from large surfaces is that wake regions can entrain ambient air into clean zones. A consideration of the impact of Grade B areas upon Grade A zones should be considered in such circumstances. Ideally, the pattern should show that the air is characterized by a smooth flow, free of any disturbances (such as small and temporary vortices or eddies) and unimpeded.
应该检测到任何停滞的区域。当单向气流遇到物体时，会形成尾迹和涡街。这就造成了湍流。这可能导致机械和工作表面前面的口袋停滞，垂直于气流的主要方向。这样的口袋可能在速度和方向上不可预测，需要绘制地图。大表面的另一个潜在风险是尾流区域会将周围空气带入清洁区域。在这种情况下，应考虑B级地区对A级地区的影响。理想情况下，这种模式应该显示出空气的特点是平滑流动，没有任何干扰（如小的和暂时的漩涡或涡流）和畅通无阻。

From the above, the importance of airflow patterns is demonstrated and it is arguably more important to ensure that an appropriate airflow pattern is in place than with seeking to achieve an airflow within a particular range. However, even where a case can be made to vary the airflow velocity it remains important to measure airflow velocities at commissioning, periods of requalification and at the start and end of each test session to ensure consistency and to verify that airflows remain within validated parameters. Where airflows are found outside of range it is important that an airflow velocity study be conducted in the ‘as found’ state to assess whether the air pattern have changed to the extent that they pose a contamination concern. This leaves one question to consider: where, in terms of position, should airflow velocities be assessed?
综上所述，气流模式的重要性得到了证明，确保适当的气流模式比寻求在特定范围内实现气流更重要。然而，即使在可以改变气流速度的情况下，在调试、重新确认期间以及每次测试的开始和结束时测量气流速度仍然很重要，以确保一致性，并验证气流保持在验证参数范围内。如发现气流超出测量范围，必须在“已发现”状态下进行气流速度研究，以评估空气型态是否已改变到可能造成污染的程度。这就留下了一个需要考虑的问题：就位置而言，应该在哪里评估气流速度？

Airflow Velocity Measurements: Working Height or Filter Face

European regulatory guidance indicates that airflow velocities should be measured at working height. This leads to two considerations. First, what is working height? And second, is working height the correct location to select, especially as a determinant of airflow patterns as described above.
欧洲监管指南指出，风速应在工作高度测量。这导致了两个考虑。一、什么是工作高度？第二，工作高度是选择的正确位置吗，尤其是作为上述气流模式的决定因素。

Assuming first that working height needs to be measured, this is something to be determined by the user. For aseptic filling, for example, an appropriate definition of working height would be a point just above the vial neck opening, to ensure that any particles that might enter the air-stream are directed away from the open neck position. The complexity that emerges from this is that there will be various ‘working heights’ should vials of different sizes be used on a given line.
假设首先需要测量工作高度，这是由用户决定的。例如，对于无菌灌装，工作高度的适当定义是刚好高于瓶颈开口的一点，以确保任何可能进入气流的颗粒都被引导远离打开的颈位置。由此产生的复杂性是，如果在给定的生产线上使用不同尺寸的小瓶，就会有不同的“工作高度”。

However, is working height the right location to measure airflow velocities? With airflow velocity studies, the measurement of the velocity at the working position can be highly variable due to the equipment size and configuration within the unidirectional airflow device and it can be argued that proper airflow pattern at the working position is more important than achieving the specified airflow velocity at the working position. In a sense, the velocity measurement at the working position is more for information purposes in terms of helping to understand the observed airflow pattern. This means that the FDA guidance in relation to ensuring consistent measurements below the filter face is more accurate predictor of airflow patterns than the European position of measuring airflow velocity at working height.
然而，工作高度是测量气流速度的正确位置吗？在气流速度研究中，由于单向气流装置内的设备尺寸和配置的不同，工作位置的速度测量可能会有很大的变化，可以说，在工作位置适当的气流形式比在工作位置达到规定的气流速度更重要。从某种意义上说，在工作位置的速度测量更多的是为了帮助理解观察到的气流型。这意味着FDA关于确保过滤器表面以下一致测量的指导比欧洲在工作高度测量气流速度的位置更准确地预测气流模式。

A final point to make is that if there are areas of concern arising from airflow visualization studies then these are be partly verified through environmental monitoring (16). This is notwithstanding some of the inherent weaknesses associated with environmental monitoring. However, trend data can be particularly useful for assessing clean air device performance particularly if a problem is detected at a later stage such as an airflow velocity reading out of range or damage to HEPA filter media. Satisfactory environmental monitoring data, provided the monitoring locations are representative of contamination concerns, can be a useful risk mitigation factor.
最后要指出的一点是，如果气流可视化研究中出现了一些值得关注的领域，那么这些领域可以通过环境监测得到部分验证（16）。尽管在环境监测方面存在一些固有的弱点。然而，趋势数据对于评估清洁空气设备的性能特别有用，特别是如果在后期检测到问题，例如气流速度读数超出范围或HEPA过滤介质损坏。令人满意的环境监测数据，如果监测地点是污染问题的代表，可以是一个有用的风险缓解因素。


Summary

In summary, the consensus of the regulations, especially as enshrined in European GMP, is for airflow velocities of 0.45 ms-1 (90 feet per minute) +/‐20%. However, these values are arbitrary and their origin lying in the early days of cleanrooms. Hence other velocities maybe more suitable for achieving contamination control. The way this can be achieved is through focusing on airflow visualization. If a company intends to do this, it will be important to ensure the rationale and justification are sound. The rationale will need to include:
总而言之，法规的共识，特别是在欧洲GMP中，是0.45 ms-1（90英尺/分钟）+/‐20%的气流速度。然而，这些值是任意的，它们起源于洁净室的早期。因此，其他速度可能更适合实现污染控制。实现这一目标的方法是通过关注气流可视化。如果一家公司打算这样做，重要的是要确保理由和理由是合理的。理由将需要包括：

The “operational” airflow visualization under the actual ranges.For the height at which the velocity is measured (either the working position or, more appropriately, below the filter face) is recorded and justified.
In addition, it is good practice that where airflow velocities need to be adjusted, that airflow visualization patterns are always repeated before any processing recommences. Here airflows are a critical factor affecting the distribution of particles within a clean space (17). Moreover, it is similar best practice for environmental monitoring locations to be selected in relation to airflow visualization patterns.
实际范围下的“可操作”气流可视化。对于测量速度的高度（工作位置，或者更恰当地说，在过滤器表面以下）进行记录和证明。
此外，在需要调整气流速度的地方，在任何处理重新开始之前总是重复气流可视化模式，这是一个很好的做法。这里气流是影响洁净空间内颗粒分布的关键因素（17）。此外，选择与气流可视化模式相关的环境监测位置也是类似的最佳实践。

lzq050628

收集很全面，点击认可了

yhgz

多谢分享！

鬼使神差

就是远古时候的一个过时的数值，还要硬保留，怕打脸又放在这打脸

渐雨听风

鬼使神差 发表于 2025-4-18 21:15
就是远古时候的一个过时的数值，还要硬保留，怕打脸又放在这打脸

哈哈哈哈，确实。
一句话，你要啥在50年前搞研究，研究出来啥数据，你都是权威