映射研究组合：真空烤箱，仓库，LN2储罐和CO2

After our webinar "Continuous Mapping" we received several questions:

Dear Paul,

We have multiple mapping applications. Please allow me to outline some of our approaches to you, so that I can get your feedback to implement potential improvements to our procedures.

方案1：

We have a vacuum oven that has 10 shelves which generate heat. On each shelf there is a tray. Once the tray is too large to manage, we replace it with two smaller trays using the same available area.

An initial mapping is performed using the original large tray. Once that's done, we will replace that tray by two smaller in each shelf with the same material, should I repeat a mapping study with the two smaller trays?

方案2：

我们的仓库只有在夏季执行的图映射的三年常规映射研究数据。由于高温，夏天被认为是最差的案例。但是，对于我们的最初资格，我们进行了冬季和夏季地图。这些原始研究还使我们能够定义监视探针的位置。

这是当前状态：
• Monitoring Probes: one located on the hottest point and another on the coldest point.
•监视探针位置重新评估：每三年一次。

我的问题是：一旦这两个探针连接到监视系统，我们开始收集数据，可以认为这是连续映射吗？

方案3：

Based on your presentation, the three-year routine mapping studies to re-assess monitoring probe placement must consider the winter and summer seasonal period.

如果在极端条件下安装了两个监测探测器，并且夏天被认为是最糟糕的时期，那么在最初的冬季研究后，我们为什么要考虑冬季映射？
预先感谢您的回复！
-L

Paul wrote:

Thank you for joining our webinar and for asking great questions!

方案1：

首先，我要说的是，映射真空烤箱是具有定义的开始和结束的动态过程的验证或资格，以及必须在最后实现的产品标准（例如干燥或重量的变化）。
This is very different type of mapping process than mapping for storage. Just to be clear, the recommendations I gave in the webinar were for storage. Some of the principles cross over, of course, but please understand that the presentation was focused on mapping for storage. Nonetheless, I will try and answer your questions.

In the case of a vacuum oven, I would repeat the mapping. Using a different tray, of a different size, or a different material, will change how heat is transferred from the heated shelf to the tray, and could change the end performance and the amount of heat delivered to each product location.

方案2：

This is not continuous mapping as outlined in the webinar. Yes, it is continuous, but it is not mapping. Mapping cannot be performed with only probe locations. I think you are assuming that the hot and cold spots will remain the same over time. You cannot prove this when you only gather data from two locations. Continuous mapping involves a high density of sensors continuously sampling.

方案3：

冬季/夏季更好地解释为“最具挑战性的季节”或“一年中最热门，最冷的部分”。如果您在您地区的寒冷季节不够寒冷，无法在仓库存储中出现问题，那么冬季可能不需要映射。但是您仍然需要做一些事情，例如提供有记录的理由，为什么您的设施不进行冬季地图。

Overall:
I would question a decision to monitor a warehouse with only two sensors, one each in the identified hot/cold spots. This assumes that the warehouse’s temperature dynamics don’t change, except by season. But we know that warehouse conditions change for many reasons, for example, equipment failure, or personnel changing setpoints without following procedures, or doors accidentally left open.

Probably the most common activity that changes conditions is items being placed in a way that alters air flow and heat distribution. This alone affects where hot and cold spots are located and that can’t be detected by two sensors. Unless your warehouse is quite small (less than 100 cubic meters), I would add some additional monitoring locations. While you are expected to monitor the hot and cold spots, you are misinterpreting the guidance and the practice if you are monitoring ONLY the hot and cold spot.

让我知道任何后续问题！

Dear Paul,

As an industry practice, do we need to perform pre- and post-calibration checks performed before and after mapping studies for the following?
1。Vaisala温度/Humidity Loggersused in mapping environmental chamber
2。Vaisalaco₂探针GMP251andVL-4000-40C模拟记录器for CO₂chambers
3. VaisalaVL-170054TThermocouple Logger for LN2 units

Paul wrote:

Thank you for these wide-ranging questions! I’ve tried my best to answer…

First, you asked about our温度/Humidity data loggersused inmapping environmental chambers。
In general, for any temperature sensor, you would perform a pre- and post-calibration check when mapping. This is not written in stone, but it is the general practice especially when using sensors with that tend drift with use, such as thermocouples.

热电偶在精度上漂移的已知趋势创造了校准前后的实践。我们看到的是，老年检查员和审计师希望看到这一步骤。但是，我们确实有映射服务提供商作为使用我们的登录器的客户，并且没有进行校准前和校准 - 他们只是验证了工厂校准证书。这是基于设备的已知稳定性以及提供商的经验。这些服务提供商在Vaisala产品方面具有足够的经验，他们知道映射数据记录仪的不经常将无法进行校准。

从我们自己的内部研究中，我们可以看到我们的数据记录器失败校准，大约有2％的时间。但是，由于您没有这种经验或数据需要依靠，因此我只会安全地进行播放，并做一个简单的记载前和后车。没有什么想象的，只需将映射记录器（和参考记录仪）放在研究之前和之后的一个小时的空间中的一个小框中，并证明所有值都在参考记录器的0.2°C之内。

您的下一个问题是在CO上₂探针GMP251and VL-4000-40C Analog data logger forco₂chambers。
从技术上讲，您不会使用这些映射。气体往往会如此迅速地扩散，以至于几乎立即达到平衡，尤其是在封闭空间中。如果您同意，那么您可能只是在一个点进行测量。如果是我，我只会验证会议厅的综合公司₂sensor was calibrated.

But if you want to monitor CO₂independently during the mapping, I expect that some sort of calibration verification would be appropriate. Do you have any reason to expect that the CO₂您打算使用的传感器在研究期间会大大漂移吗？如果您没有很多历史数据₂sensors, it’s useful to do a pre-calibration and post-calibration
However, calibration of these devices is not as simple as with a temperature sensor, but there probably is a nice simple point of use check you can do if you have another calibrated instrument to use as reference. We aren’t looking for a full calibration here… just a quick documented check to show why you think the instrument is accurate.

Finally, you mentioned Vaisala VL-170054T Thermocouple Logger used inLN₂units。如果您正在映射，尤其是使用热电偶，我肯定会进行校准和校准后检查。同样，这不一定要复杂，足以记录传感器的准确性。

请注意，在液氮温度下，热电偶有很多错误。根据我的经验，映射LN₂单位很困难。我不得不绘制一些LN₂storage dewars back in the day and we eventually managed to get it done. But we weren’t really able to conclude much, other than radially symmetric spaces are hard to map and the largest contributor to temperature variation were inherent insulation faults due to the method of construction of the vessel.