SiHuB Sensor Calibration System

Generate accurate test mixtures of VOCs and humidity for breath sensor calibration

  • Accurate, precise and repeatable calibration gases
  • Traceable to primary standards
  • Concentrations from part per billion to part per million levels
Find out more about breath sensor calibration


A revolutionary setup built on the established GEN-SYS technology

Owlstone SiHub system

As part of efforts to develop breath diagnostics technology at Owlstone, it was necessary to be able to create controllable mixtures of different gases to test our breath sensors. We drew on our existing GEN-SYS range to create a setup capable of generating mixtures of multiple gases, with controllable humidity levels, in order to mimic the conditions in which breath sensors would be deployed. Using permeation tubes to provide the test compounds, SiHuB provides a simple and flexible alternative to using multiple gas cylinders to supply the test gas mixtures. This setup has been used extensively as part of our LuCID project, as well as by breath research groups at institutions including the University of Amsterdam and Universität Ulm.

  • Reliable

    Accuracy and precision even at very low concentrations with superior long term stability and repeatability

  • Economical

    Cost saving by replacing multiple, costly gas cylinders

  • Safe

    Small quantity of target chemicals reduces risk of dangerous exposure

  • Simple to Use

    Fast and easy sample replacement removes dangers associated with high pressure cylinders

  • Space-saving

    Compact footprint for significant laboratory space savings

  • Traceable

    Owlstone permeation tubes are traceable to NIST standards, and are supplied with their own calibration certificates

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How it works

How does sensor development with SiHuB work?

A typical workflow in sensor development for breath diagnostics might look something like this:

  • Stage 1: Can the sensor detect the compound of interest?
  • Stage 2: Can the sensor detect the compound at the required concentration levels?
  • Stage 3: Can the sensor still detect the compound in a background of other compounds typically found in breath?
  • Stage 4: Can the sensor detect the compound if the sample is also at humidity levels representative of breath?
  • Stage 5: Can the compound be detected in a sample of real human breath?

SiHuB allows each of these stages to be performed in turn. In steps 1&2, the output from a single vapor generator provides a controllable concentration of the compound under investigation. In stage 3, combining the outputs of multiple vapor generators allows a matrix of gases approximating the makeup of human breath to be generated. In stage 4, a humidity generator is used to add humidity to the gas mixture. Finally, in stage 5, the sensor is ready for testing with real breath samples, collected by a sampler such as the ReCIVA.

Simulating human breath with SiHUB: Learn more about calibrating gas sensors

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The Owlstone Vapor Generator (OVG-4) is a compact, cost effective calibration gas system, which can generate NIST traceable, precise, repeatable and accurate concentrations of chemicals and calibration gas standards. Designed for calibration of industrial and scientific gas sensors, the OVG-4 incorporates permeation tube technology and can replace multiple gas cylinders.

OVG-4 Specifications


The Owlstone V-OVG is a system for generating precise, repeatable trace concentrations of gases. By using permeation and diffusion tube technology, a range of concentrations from low parts per billion to high parts per million levels can be achieved. The large permeation oven allows the use of up to 6 permeation tubes to create multiple-component mixtures, or a diffusion tube to generate high ppm concentrations.

V-OVG Specifications


The OHG-4 is a versatile humidity generator that is used to produce a range of relative humidity concentrations from 1 to 90%rh (±1%). Designed to be used in conjunction with the OVG-4 and V-OVG to generate a wide range of vapor standards for calibration of sensors.

OHG-4 Specifications

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Research case studies

SiHuB's real-world applications

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