Q&A "From Monitoring to Controlling with Hydrogen Peroxide Sensors"
If you haven't yet seen our latest webinar on monitoring and controlling bio-decontamination processes, you can still watch the recording:
From Monitoring to Controlling with vaporized H2O2 Sensors: Why, How & a Case Study
For this webinar, we welcomed two experts from vapor generator manufacturer Cleamix for a case study on hospital room bio-decontamination.
Because Cleamix integrates Vaisala's HPP270 hydrogen peroxide sensors, the answers below pertain to both Vaisala's sensors and Cleamix vapor generators.
If you have questions - please post below in the comment section and we will get back to you!
What indicators are used in a typical hospital room decontamination process?
At Cleamix we have used 3MTM ComplyTM Hydrogen Peroxide Indicator Tape as chemical indicator for instant information on the exposure to the H2O2 vapor. We also use Biological Apex indicators, inoculated with 106 Geobasillus stearothermophilus spores on stainless steel, used for gaseous hydrogen peroxide; these come from MesaLabs.
What is the duration for an effective bio-decontamination using vaporized hydrogen peroxide?
Bio-decontamination duration depends on the size of the room, the number of items and the types of materials in the room or chamber. Existing humidity and temperature determine the maximum theoretical H2O2 ppm level, but the actual concentration achieved (and therefore the process time ) is always dependent on the environmental factors. Each enclosure should be validated for optimal process parameters.
At what level of hydrogen peroxide ppm is it safe to enter the decontamination area?
The bio-decontaminated area can be taken back to normal use once the H2O2 concentration gets below 1 ppm. Once ppm is 7 ppm or less, the hospital room can be entered for opening windows etc to accelerate the aeration.
How does humidity affect a hospital room decontamination process?
It is easier to generate high concentrations of H2O2 vapor in dry conditions, but high humidity can actually enhance the decontamination especially when low H2O2 concentrations are applied. Humidity can be seen as a good thing as long as a sufficient concentration of H2O2 vapor can be generated within the enclosure without reaching condensation.
What are the benefits of controlling H2O2 vapor injection using the real-time hydrogen peroxide vapor value?
In controlling processes, we would base our bio-decontamination cycles on real-time measurement results rather than the predetermined injection profile of H2O2 liquid. This gives us more flexibility and better information on changes in environmental variables during decontamination cycles. Real-time measurement automatically decreases variability of conditions from batch to batch and leads to more stable ppm levels in our processes. Additionally, real-time measurement reduces our validation efforts. Overall this method of bio-decontamination (monitoring and control) follows the PAT (Process Analytical Technology) ideology. We know exactly what is happening in our processes and we are able to act immediately if something goes wrong.
What are the benefits using inline measurement instead of indicators?
The main benefit is continuous real-time measurement data that allows you to monitor temperature, humidity and H2O2 ppm values. This helps ensure the process is working as planned and can decrease the number of indicators needed because you can rely more on an inline measurement data. Further, this method allows you to include inline measurement values in your validation results for better documentation and reporting during batch manufacturing and validation runs.So long as your instrument has good repeatability, you can control the process with it. For example you could control a vapor generator with on-line measurement values.
In what applications are inline measurements used for controlling the H2O2 vapor?
We see use of Vaisala sensors for controlling room bio-decontamination in hospitals, ambulances, isolators and transfer hatches.