Monitoring and Controlling VHP® Sterilization Cycles

Vaporized hydrogen peroxide (VHP®) is a vacuum sterilization process that operates under low-temperature conditions and has traditionally been used for small objects such as reusable medical instruments, pharmaceutical containers, pre-filled syringes, electronic medical devices, and moisture or temperature-sensitive materials. But in an ever-growing market, VHP® sterilization applications can range from:

  • Single-chamber units for small objects
  • Pass-through chambers for transferring objects between areas in the pharmaceutical industry
  • Mobile cart units for decontaminating small to medium-sized spaces or rooms up to complete facilities
  • Complete integrated systems for bio-decontamination of large spaces, or complete facilities.

The fast-paced progression of VHP® is due to its ability to break down hydrogen peroxide (H2O2) into environmentally safe by-products (water H2O, oxygen O2), and the potential health hazards associated with the alternative method of Ethylene Oxide (ETO) gas sterilization.

The VHP® process has three phases: conditioning, sterilization, and aeration/post-conditioning. These phases occur in a single chamber under deep vacuum conditions usually in the range of 1-10 millibar (0.03-0.3 inches Hg), with a typical temperature range of 28-40°C (82-104°F). The total cycle time varies depending on several factors including cycle temperature, the type of object (component, assembly, material, etc.), and the weight of the load.


Application Challenge:

Finding critical components with exceptional accuracy and repeatability for monitoring and controlling the process variables through all phases that occur in VHP® Sterilizers.


Precise, consistent control and monitoring of variables such as temperature, vacuum pressure, RH, and H2O2 (Hydrogen Peroxide) vapor delivery is required for an effective vaporized hydrogen peroxide sterilization process. A simplified graphic example is shown below.

Application Solution:

Gems Sensors & Controls and Setra provide key components across several product lines to ensure long-lasting dependable results in stand-alone VHP® Sterilizers, bio-decontamination equipment, and integrated systems. Accurate, Reliable, Stable, and Repeatable. Gems & Setra offer a robust product portfolio with an excellent price-to-performance ratio.

Setra Model 730 Vacuum Capacitance Manometer

  • High Accuracy: ±0.25% of Reading 
  • Tensioned Diaphragm Provides Superior Performance 
  • Wide Compensated Operating Temperature 
  • Fast Response Time with Low Circuit Noise 
  • Not Sensitive to Environmental Changes 
  • Exceptional Overpressure Design 
  • CE & RoHS Compliant

CAL 3200 Simple PID Temperature Controller

  • 32nd DIN Compact Single Loop controller
  • 1 x 4 digit LED display with 2 output LED
  • Easy-to-use autotuning
  • Simple menu-driven configuration
  • Removable terminal block for easy wiring.
  • IP66 protection
  • Output Functions - Heat, Cool, Alarm
  • Input Type - Thermocouple, RTD, Linear: 0 to 50mV
  • Control Type - PID heat only, PID heat cool , ON/OFF
  • Certifications - CE, UL

KS98-2 Microcontroller

KS98-2 Modular Automation System

  • Multi loop control, Profile control, Sophisticated process control
  • Complete automation of small applications
  • Embedded data logger
  • Operator Interface with Color Display & Touch
  • User defined application screens
  • Alarms and alerts with Icons or clear text
  • Always accessible USB interface on front fascia
  • Expandable with modular inputs and outputs
  • Ethernet and common fieldbuses
  • Simulator to test before installation


Other Gems Product Offerings for Vaporized Hydrogen Peroxide Sterilization:

LS-1755 Single Point Level = Liquid H2O2 supply reservoir (small chamber-type units)

LS-700 Multi-point level = Larger Liquid H2O2 reservoir (large chamber-type units, mobile decontamination units)

LS-800 Multi-point level = Largest Liquid H2O2 reservoir (integrated bio-decontamination system for room or facility)

MaxVU Rail Compact DIN-rail mounted PID Temperature Controller = Basic temperature control behind the cabinet

Gems Solenoid Valves = Liquid H2O2 and vapor injection on/off and directional control


Gems Sensors and Setra’s products have been field-tested around the world. Partner with us for product solutions in your Vaporized Hydrogen Peroxide sterilization application today.