Some of our customers have applications that require measurement transmitters to be installed outside, so the Vaisala Indigo500 and its family of smart probes have been designed to be durable enough for these kinds of rough, tough conditions. For example, when measuring humidity in gas turbine intake air or in combustion air for diesel generator stations you need the measurement devices to be outdoors. There are also applications where it’s not desired, but outdoor measurement will be dictated by practical considerations.

In the majority of outdoor applications, the most important parameters to measure are usually humidity and temperature, but moisture-in-oil measurement for transformer applications is also necessarily an outdoor application. Another common outdoor application is CO₂ measurement for demand control ventilation in buildings – this sort of application really benefits from the Indigo500’s ability to support multiparameter configurations as you can keep the instrument on the roof of your building and use another probe to measure relative humidity, for example.

The three major challenges of outdoor use

Instruments for outdoor use need to be robust enough to stand up to three main challenges: a wide temperature range, the weather, and solar radiation or UV. Temperature is one of the easiest parameters to validate, and the Indigo500 has been tested and validated in a climate chamber to ensure that the device can not only withstand the extremes of outdoor temperatures, they can also endure the rapid changes of dynamic, cycling temperatures.

The main challenge of weather is water ingress into the device, so we validated the Indigo500 using Ingress Protection (IP) testing, which involves exposing the unit to water sprays, ensuring the robustness of the overall mechanical construction. Another way in which water can enter the housing is as a vapor, and this has also been taken into account in the design. A breathing element on the reverse allows water vapor to stabilize between the inside and outside of the transmitter housing, preventing condensation and pressure changes inside the housing arising from the changing temperature. The latter may cause under pressure in the housing when the warm enclosure is exposed to cool water showers, which in turn increases the possibility of water ingress into the housing – a test called “tropical rain” by test engineers.

To protect against solar radiation, we chose aluminum alloy as a construction material because it withstands UV and won’t degrade. A special surface treatment provides protection from oxidation and rust build up. All these factors have been designed into the Indigo500 and validated in environmental tests throughout the R&D process to make sure it can stand up to the demands of all kinds of outdoor applications. Finally, we’ve been testing the Indigo500 outside in the field for the last two winters in southern Finland, with no problems to report despite constant damp and rainy weather.

Accurate measurements inside or out

Connecting the Indigo500 to your current systems and operations is the same process whether your application is indoors or out. Accurate measurement data can be transferred using the same system interfaces and connectivity, including analog outputs, binary contact relays, Ethernet, and local interfaces such as the touch panel display.

Although outdoor applications are not the primary use for the Indigo500, we followed strict design requirements to ensure it meets the same standards as outdoor devices. And of course, if it is tough enough for outdoor applications, it means it is also robust and dependable for indoor applications too. Wherever you use it, the Indigo500 is designed to be relied upon for dependable and accurate measurement data for many years.

Learn more about Indigo500 Series Transmitters >

Or get in touch to find out more >

Dual-probe support refers to the ability of a single transmitter or monitoring device to interface with two independent measurement devices, and then display, record, and transmit their data. It allows multiple parameters, or redundant parameters to be more easily monitored in the same space, or in different locations.

What are the benefits of using two probes measuring two different parameters?

Often an environment or process requires monitoring in multiple locations, and for a number of different parameters. It is common to be monitoring both the inlet and exhaust conditions of a single process to ensure product quality and energy efficiency. When the mounting space is limited, one transmitter with two probes is a useful and practical choice, for example, oil processing facilities with multiple oil dehydrators, or bread-proofing (multiple ovens) where one transmitter could monitor two separate ovens.

The life science industry often monitors multiple parameters in a single space, requiring multiple sensors. Certain applications, such as hydrogen peroxide bio-decontamination, may also require multiple measurement locations in larger spaces, should there be variances of temperature and air flow.

In each of these cases, a single transmitter could be used to simplify communications and provide a cleaner installation. This will reduce installation cost and effort in some cases, and lead to a lower cost of ownership.
 
Overall, the benefit of using two probes to measure two different parameters is to expand your awareness of the conditions in a space or process. If multiple variables affect the product quality or the energy efficiency of the operation, not being limited by one measurement device can offer better insight and information to make control decisions. 

What combinations could I use?

The probe combinations are many, as Vaisala offers smart probes for a variety of measurement parameters: humidity, temperature, dew point, carbon dioxide, moisture-in-oil, and vaporized hydrogen peroxide. There are no probe combination limitations for any of the available smart probes.

Measurement in life science incubators is continuous with many calibration checks. Therefore, an incubator might use a combination of the GMP251 CO₂ probe alongside the HMP9 humidity and temperature probe to ensure the correct Ph and humidity level.

Fluidized bed driers, plastics drying and applying coatings to capsules are applications that might use a combination of a dew point probe at the drier inlet, and a humidity and temperature probe at the outlet. 

High humidity applications that involve significant levels of condensation might use a heated probe for moisture levels, alongside a temperature probe to calculate variables such as relative humidity.

Advanced compressed air driers might use two dew point probes to monitor the drier outlet as well as the purge air to increase energy efficiency.

And oil processing operations might want to monitor both the moisture in the oil they condition, along with the air dew point to ensure the dryness of the vessel being filled with oil.

Which Industries and applications would benefit most?

There are several applications that could benefit from a transmitter with dual probe support. Any application that uses air to feed a process, and then monitors the exhaust to determine the effectiveness of that process can use dual probes for the inlet and outlet. Basically, any process that needs to measure before and after conditions can use a transmitter with dual probe support. Energy resources and process duration are directly affected by these conditions, and real time control decisions can be made to maintain or protect product quality.

Additionally, applications that require similar measurements in different locations can use remote probes tied to a single transmitter. This allows for simplified power delivery and communication support. With the Vaisala Indigo500 Series, the Power over Ethernet option will require only one Ethernet cable to power and communicate with two measurement devices for a wide range of parameters.

Another benefit is be the ability to exchange the measurement probes from the transmitter, without removing the installed transmitter. This will help with calibration efforts, as spare probes can be easily rotated into service. This also provides flexibility should the process conditions change, and different conditions are being measured. For example, if a manufacturer of a dryer or environmental test chamber is supplying instruments for different customer conditions; standardizing on one transmitter type, and then being able to offer probes for different conditions will simplify their offering and provide maximum flexibility to their customers. 

Learn more about the Indigo family or contact us for more information.
 

In our recent webinar, “Achieving Effective H₂O₂ Bio-decontamination in Facilities & Containment Systems” we did not have time to answer all questions, so we answered by email afterward. In this blog, we share the questions and answers in three categories: bio-decontamination process development, low ppm measurement, and condensation.

Bio-decontamination Processes

QUESTION: Are representative locations sufficient to prove bio-decontamination?

ANSWER: I assume that you are asking if vaporized H₂O₂  is measured in representative locations, that this would be sufficient to prove bio-decontamination. The answer is that once a process has gone through a validated cycle development, then proper monitoring will suffice until the next cycle requalification is needed. However, inline monitoring of vaporized H₂O₂ monitoring is not a substitute for validation of the process using chemical, biological, or enzymatic indicators..

QUESTION: How is ppm (in terms of hydrogen peroxide concentration level) connected with effective bio-decontamination?

ANSWER: The combination of temperature, vaporized H₂O₂ ppm levels, and exposure duration are used to estimate the effectiveness of a bio-decontamination process. Other variables, like materials, temperature, relative humidity, relative saturation; all are involved. But it’s most important to understand that they are all connected

QUESTION: Is ppm concentration correlated to effective bio-decontamination? I ask because sometimes, a process at low concentration H₂O₂ ppm cycle will pass, and sometimes a high concentration H₂O₂ ppm cycle will fail…

ANSWER: The vaporized H₂O₂ ppm concentration required for a bio-decontamination process depends on a number of variables, including the type of micro-organisms, the space being bio-decontaminated and challenges associated with the space, such as the objects within it. It is possible that certain areas or processes require a longer duration at lower ppm levels, where others require higher ppm levels for shorter durations. There is no single correct method. The process you are using should be developed under conditions that are representative of a normal cycle.

QUESTION: Does altitude affect humidity and saturation during bio-decontamination?

ANSWER: Yes, altitude does affect the relative humidity and therefore relative saturation. The relative humidity and relative saturation can be expressed in terms of the partial pressures of water and vaporized H₂O₂ relative to the total saturation vapor pressure (the amount of the gas the air can hold at a specific temperature) of each gas. This relationship is linear with pressure changes, so the drop in pressure at altitude needs to be corrected for during measurement.

QUESTION: Why does H₂O₂ concentration vary at the end of a vaporized cycle, during aeration and afterwards, when a 1 ppm concentration is not reached?

ANSWER: Aeration time is going to vary from area to area, with a number of possible variables. The examples provided in the webinar were basic representations. The 1 ppm limit is a safety guideline for exposure over an 8-hour workday and is sometimes a goal in the aeration process. Different factors can affect this target level for aeration, namely material desorption, condensation effects, and chemical compatibility. Sometimes the aeration target is in the ppb levels for vaporized H₂O₂.

QUESTION: Why is vacuum vaporized H₂O₂ used for sterilization applications?

ANSWER: Vacuum conditions are typically related to the vaporized H₂O₂ delivery and aeration of the process. One method uses a deep vacuum to pull liquid hydrogen peroxide from a disposable cartridge through a heated vaporizer and then, following vaporization, into the sterilization chamber. 

In another approach, vaporized H₂O₂ is brought into the sterilization chamber by a carrier gas such as air using a slight negative pressure (vacuum). There may be other benefits and concerns for performing the cycle under vacuum as well. Aeration is typically performed using fairly powerful suction as well.

QUESTION: How long do you have to hold the conditions at 100% saturation to get effective decontamination?

ANSWER: The decontamination phase of the cycle is going to vary in length, depending on a number of variables determined by process development. Factors to consider are; the type and volume of the space being bio-decontaminated, the types of micro-organisms being neutralized, and the contents and the materials present in the space. The typical process times vary widely. For example, room bio-decontamination can range from 4 – 24 hours, whereas isolator bio-decontamination processes may only last 1-4 hours.

QUESTION: Is there a rule of thumb for how much liquid volume of peroxide is consumed per bio-decontamination process? I am thinking of a number in terms of milliliters per cubic foot of meter for 35% or 50% H₂O₂.  Obviously, there are many factors: the shape of the room or item being decontaminated, level of log reduction desired, etc., but if you have a value in mind, I'd be quite interested.

ANSWER: Unfortunately, I do not have a very good answer to your question, as the type of generator we use is customized, and I don’t know if we have tracked the consumption of liquid H₂O₂ use. Also, vapor generators vary in output and flow rate, so it’s difficult to give an answer on this, but I would recommend contacting the vaporizer manufacturer.  They produce and sell vaporized H₂O₂ products and services and will likely have better information for you.

Low ppm Measurement

QUESTION:  Is the 1 ppm for H₂O₂ a European standard?

ANSWER: The European Chemicals Agency ECHA has an evaluation document "Regulation (EU) No 528/2012 concerning the making available on the market and use of biocidal products"

In the US, the ACGIH, OSHA, and the National Institute of Occupational Safety and Health (NIOSH) all have set an average daily occupational exposure limit of 1 ppm.

QUESTION:  How does the Vaisala hydrogen peroxide probe measure low concentration? 

ANSWER: Currently, HPP270 products measure down to 0 ppm with accuracy ± 10 ppm the minimum. Therefore, Vaisala does not offer a measurement solution designed specifically for low level vaporized H₂O₂ measurement. There are a number of solutions on the market, and I would refer you to the reference materials we provided for more insight into low-level measurements.

QUESTION:  If the lowest concentration level measured by the HPP270 is 10 PPM, how do we know when it is safe for operators to re-enter a decontaminated area?

ANSWER: The HPP270 Series probes are designed for in-line, process-level measurements. Those measurements can be used to manage vaporized H₂O₂concentrations during the decontamination phase. The HPP270 probes were not designed for safety level measurements. The duration of aeration (after cycle development and validation) can account for the evacuation time required, and the rate of change from the HPP270 series probes’ real-time measurement can aid in that estimation. There are other low-level measurement options currently available.

Condensation

QUESTION: Which method is more effective in bio-decontamination: Dry or wet (with visible concentration)?

ANSWER: The effectiveness of wet vs dry vaporized H₂O₂ bio-decontamination is a hotly debated topic. This is another item that should be determined by process development. In general, Vaisala sensors are good choice for both cases and provide accurate and stable measurements even during high-condensing processes. Condensation is why the HPP270 probes provide the relative saturation value; this is the only parameter that allows us to estimate when condensation will occur.

QUESTION: Can we achieve micro-condensation with spraying H₂O₂ through atomizer nozzle?

ANSWER: Micro-condensation is a condition created with a careful balancing of the relative humidity, relative saturation and temperature of both the air space and the surfaces in the space. However, Vaisala does not manufacture vaporizer or atomizer products so I cannot comment on the delivery capabilities of an atomizer, as most of our experience is related to hydrogen peroxide vaporization.

QUESTION: Is condensation recommended during a process?

ANSWER: This is debated in the scientific community and there is no clear consensus. In micro-condensing processes, there is actually an invisible condensate formed during the process, but being at sub-micron level, it is invisible to naked eye. This is achieved by maintaining the relative saturation extremely close to 100%. There are scientific papers that suggest that micro-condensation is necessary in hydrogen peroxide bio-decontamination and that micro-condensation can happen in dry processes as well. We recommend a review of the research that focus on processes similar to your own.

The term “machine learning” was coined by Arthur Samuel as long ago as 1959, with research into the topic – closely linked to research into artificial intelligence (AI) – continuing through the decades that followed. But at this point it was ahead of its time – computing power wasn’t yet sufficient to yield the opportunities promised. It is only now that we can start to see the fruits of these early labors, with far greater computing power, increasing amounts of digitized information, and the ability to easily share data via the internet. 

A cloud-based revolution

The next industrial revolution has already begun – there have been major changes and developments with cloud platforms in the last five years, with industries benefiting massively from the availability of increasingly standardized commercial offerings. This has brought opportunities for a large amount of data to be processed and analyzed, as well as making data easier to access. Connected Internet-of-Things (IoT) devices and cloud availability are providing the platform for what will come next – and undoubtedly it will involve AI and machine learning.

For the last few years there have been efforts in many industries to collect data without really fully knowing how to use it. Machine learning and AI are the missing piece of the puzzle – a solution that has been waiting decades for its problem. In 2020 we finally have the computing power to make use of machine learning, with the ecosystem and environment ready and waiting. We can take the data from all these connected devices in the cloud and find new opportunities with AI. No one knows exactly what will happen, but I’m sure there will be value to be realized and valuable new insights to uncover.

Keeping data secure

When talking about risks associated with AI and the cloud, people immediately think of cyber security. Obviously cyber security is of the utmost importance in modern society, but the level of risk assumed is sometimes overstated. The cloud is not inherently insecure – it can in fact be in some ways more secure than having data on your personal computer, or on a server in your basement. Commercial cloud providers have hundreds if not thousands of people working on security; it would be hard for any company to put the same amount of effort into security in a non-cloud environment. We are seeing a turning point in industry where we all realize security is essential, but there is a growing understanding that the cloud might actually be the safest place for our data.

The big risk of bad data

But there is another, less obvious, risk than a cyber-attack. AI might be able to crunch a lot of data and learn a lot of things, but the learning – and consequently the decisions based on it – are only as good as the data you put in. In a nutshell, bad data in means bad decisions out. It’s important to get the facts and the base data right – even all the computing power and data points in the world can’t rescue you from bad data. For measurement applications, it’s essential that the original sensing information is accurate in the feed data; in other applications there are also ethical considerations to be made: data must be accurate but also fair and unbiased. For example, if an AI recruiting system learned what constitutes a good candidate based on a certain dataset of previous hires, no woman would ever be given a job! 

The robots are not coming for our jobs

While it’s hard to foresee all the impacts of machine learning on the different jobs people do, it’s unlikely that large segments of the workforce will be replaced by machines. If we take industrial process measurements for example, we’ve already discussed how essential it is that measurement data is correct, so we’ll still need competent people choosing what parameters to measure, what equipment to use, how to install it to ensure accurate measurements, how to take representative samples, and much more. Without this, AI and machine learning will fail and we will waste the opportunities they present. Man and machine will need to work together in the future, just as we do today. 

Working to provide good data

Vaisala always wants to bring value to customers in the field of industrial measurements by offering the best products on the market. To do this we are constantly innovating and looking for new opportunities. The value of good measurement – measurements that are stable, reliable, and accurate – is becoming more and more important; whether you’re looking to optimize industrial processes, achieve high-quality output, develop a circular economy, or optimize energy usage, you need high-quality measurements. We are also looking at how we can add more value to our products, for example in how our customers can access past and present measurement data or receive alarms and notifications. The industry’s shift towards cloud-based systems is something that every company who wants to be providing added value should be looking into. We want to expand the business of measurement to add new levels of convenience and value, because the importance of accurate, reliable measurement data is only going to grow.

View also our previous posts around this topic: Developing future-proof solutions by Mika Väisänen, our Senior System Architect and also take a look at some of the tangible advantages of cloud-based sensing solutions that our Senior Product Manager Lars Stormbom has presented in his post Reaching for the clouds.

4 Questions your Risk Analysis Needs to Answer

Our Senior Regulatory Expert Paul Daniel is happy to answer your questions by email. This week’s blog is from an email exchange between Paul and a Senior Validation Manager of a biopharmaceutical firm.

C wrote: Good Afternoon Paul,

I’ve been performing validation for approximately 26 years, but I have a couple questions about requalifying equipment and creating policies for that procedure.  Currently, I’m revising our company procedures for Periodic Review and Requalification. I find that there is a lot of literature to review on requalification for temperature-controlled storage units/areas/stability chambers, etc.

At my former company, we performed mapping annually, which as you know, can be costly and time consuming.  I definitely want go to a risk-based approach for our requalification process, but I need some clarity on assessing risk. At first glance, every temperature-controlled unit and area seems critical and therefore in need of annual requalification.   However, in my research on risk-based analyses for mapping, that seems not necessarily the case. 

We have a continuous monitoring system with its devices calibrated annually.  I’m reviewing all of the initial validations to verify all of the proper testing was performed; that’s intuitively a good first step. My question is – what are my next steps in taking a risk-based approach to requalifying?

Specifically, what types of questions do we need to ask in our risk assessments? 

I believe we can look at trend history, alarm excursions/frequency/length from the continuous monitoring system.  I was also thinking review of the preventative maintenance on the units to check for reliability of things such as motors and door gaskets.  I really want a solid Risk Assessment that is defensible under audit and during inspections.

Can you make any recommendations? 

Sincerely,
C

Paul wrote: Dear C,
 
Happy to help.  Risk assessments are an important tool. Even better, they can, in some circumstances, save resources.

In case you haven't seen it, we have a webinar on the topic here: Risk Assessment in GxP Environments

The most important rule for risk assessments is that the scoring rules are transparent and clear.

The goal with an RA is to make it clear enough so that you feel confident that another person performing a later risk assessment on the same application will come to the same conclusions.  Simply having done a thoughtful risk assessment in the first place will look great to an auditor or inspector – because it is important information about your controlled area(s).

A good place to start is to create scoring rules. For example, what is the main function of the environment? Is it used to store expensive product, or replaceable lab reagents?  Another aspect to look at are the specifications of the environment. Does it have tight control specifications (I.E.: stability chambers)? Or is it a single critical parameter environment (I.E.: -80°C ultra-low freezers)?

Three focal points for scoring risk: 
• What is stored?
• What are the specifications?
• What is the area’s mapping history? 

Regarding the mapping history, I would defer back to a body of knowledge on calibration intervals.  In my experience, there is a surprising lack of knowledge about this in the pharmaceutical industry. But, you actually do not have to calibrate something every year just because the manufacturer recommends it.  If the device is functioning well within its accuracy specifications at every calibration, then that alone can be a risk-based argument for extending a calibration interval. 

We can apply the same logic to chambers – if it maps well and passes every time, perhaps the time between requalification can be extended.   The Application note: “Calibration and Adjustment of Humidity Instruments – Pros and Cons of Different Methods” mentions this on page 1, third column, second paragraph.

Categorizing Applications for Risk Assessment

1. What is stored in the chamber? For example, are products expensive or cheap? Or, Does the product carry a high risk to a patient if adulterated, or a low risk?
2. Are the specifications hard to achieve? Like a stability chamber ±2°C and ± 2%RH  or an ultralow freezer at NMT -60°C.
3. Would a deviation in conditions or equipment failure be immediately obvious and detectable? 
4. What is the known, documented history of the area or unit, based on past mapping studies?

 
You mentioned the trend history of the unit from monitoring system records. Much can be learned from trend history – as we see in this story from a customer.  However, that can be similar to a single-point mapping while the unit is being opened and used…  And you have to keep repeating this analysis to justify to map or not to map.  Creating rules is a good idea.
Let me know if you have any follow-up questions!

Best regards,
Paul Daniel

C wrote: Thank you Paul. We have another challenge…

We have figured out a periodic review schedule on our temperature-controlled rooms, but now we are trying to determine whether temperature requalification it should be done for 24 or 72 hours (initial studies were 72 hours).

Further, should we map under static or dynamic conditions?  We are leaning toward a 24-hour static full chamber study because we already have a study on 72 hours of empty chamber and loaded static/dynamic conditions.  What we need is simply a verification that everything is still in a qualified state.  I’ve searched high and low on the Internet and there is a lot of information about initial qualification (in all aspects of qualification/validation), but little about performing requalification/revalidation.  We have looked for guidance from WHO, FDA, EU, etc. but there little to nothing. I appreciate your help and look forward to hearing from you.

Sincerely,
C

Paul wrote: Dear C,

Your research echoes my own.  However, one resource I can recommend is the ISPE’s Good Practice Guide for Mapping of Controlled temperature Chambers. 

To summarize the relevant parts of that guide, we should remap every 1 to 5 years. We decide the interval based on history and criticality of the application.

We document our findings and use that information to create a risk assessment. The guide also recommends proposed approach; map in a loaded condition with the same sensor locations. Requalifying loaded areas can save a lot of time and effort!  Your approach is sound especially if there has been no history of malfunctions or repairs on the unit.