vH2O2 Bio-decontamination questions: monitoring, controlling and more...

Justin Walsh_Vaisala
Justin Walsh
Business Development Engineer
Published: Jun 23, 2021
Life Science
In our webinar "Monitoring & controlling with smart vH2O2 sensor technology" we received many questions we didn't have time to answer. Here are the answers.
Q: Usually decontamination cycles are time controlled. You mentioned that with the HPP270 sensors, cycles can be parameter controlled. Do you know of customers in the pharmaceutical industry who are using parameter-controlled decontamination cycles?
Yes, we currently supply our HPP270 series sensors to a number of customers to control using the vH2O2 ppm and %Relative Saturation levels. Customers include manufacturers of isolator systems, as well as vapor generator manufacturers who package our measurement with their portable systems.

Here are a couple examples:
Q: What is the response time for the Vaisala vaporized hydrogen peroxide sensor?
A: The HPP270 Series probes have a 70-second response time for a T63 confidence. Please find the probe datasheet for your reference also. In bio-decontamination, the vH2O2 concentration level is typically increased in phases of each cycle. Our testing and customer feedback shows that the HPP270 series probes follow that phasic increase quite well.
Q: Is there any restriction for the use of the HPP sensors with nebulized H2O2?
A: The HPP270 series probes will measure H2O2 in the air whether it is vaporized, nebulized, or generated with a fogger.
Q: Does Vaisala provide a mobile version of the HPP270 sensor equipped with a CFR Part11-compliant data logger, without cables, for use during cycle developments?
A: The HPP270 series probes will require a power supply to ensure the sensor heating and purge functions are operational.  While we do offer some wireless CFR Part11 compliant loggers, we do not yet have a universal input version for the HPP270s.
We hope to have this in the near future.
See the HPP270 series datasheet for power supply information.
Q: Our application is PET bottle sterilization. Any suggestion for the issue of vapor condensate on surfaces?
A: Controlling condensation might be helped with a combination of elevated temperatures, and compressed dry air. Starting the process with dry conditions will help maintain a lower saturation level longer. Other variables, such as how the vapor is generated, could contribute also.
Q: Can Vaisala's HPP270 sensor be installed in a supply line to measure ppm of H2O2? (Our application is bottle sterilization.)
The HPP270 series sensors could be installed in the supply line, so long as there is no elevated pressure.  That said, the response time of the sensor and any temperature differences would need to be accounted for, and so it would be more of a qualifying measurement than a specific indicator of what was present in the bottles themselves.
We do not have any process-line connection accessories for the probes at this time because the probes are designed for enclosure and room measurement.
Q: Can the HPP270 be used to decontaminate a purified water system?
Because the vH2O2 bio-decontamination is a surface treatment, it would not be capable of treating a purified water system beyond the system equipment by itself when it was clean and dry. We suggest looking at Vaisala K-Patents refractometers for liquid measurements.
Q: Can you set the relative humidity lower than you want?
During the dehumidification phase, the operator can dehumidify (or not) to any %RH value deemed appropriate. You would achieve this with a dehumidifier, or a temperature increase within safe levels. There is flexibility in the starting %RH level, as the bio-decontamination is a result of the concentration and exposure time to the vH2O2. To avoid condensation, a longer duration at a lower ppm might be needed if the starting %RH is higher.
Q: Examples of Cycle development with Enzyme Indicators (EIs) instead of BIs & CIs?
While biological indicators (Geobacillus stearothermophilus) are the industry standard, enzymatic indicators are an acceptable alternative for some medical and pharmaceutical applications. They are sometimes used alongside biological indicators for cycle development, and used more frequently during requalification efforts. Isolators are a good example.
Q: Is there a Vaisala solution or recommendation for vH2O2 safety-level monitoring?
A: While Vaisala does not currently have a low-level solution, there are some options on the market that can complement the PEROXCAP® measurements when safety level verification is desired. Your local Vaisala sales representative can likely recommend a sensor for low-level measurements.

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