VOC in the cleanroom

Online VOC measuring device: GO-ATC

Lead Developer Gröger & Obst GmbH Helmut Gröger

Managing Director MCRT GmbH Andreas Machmüller

Airborne chemical contaminants – so-called ACC (Airborne Contamination by Chemicals) – can cause significant problems in cleanrooms across all industries and research fields, and can even lead to product or process destruction, but also have impacts on human health.

These chemical contaminants can be released, for example, by solvent-based adhesives, machine oils, from the process itself, or from reactive floor systems, coatings, paints, varnishes, and many other materials and building supplies. They can also be drawn in from outside or released into the air of the production rooms.

One of the most important roles here is played by airborne organic contaminants, known as VOCs (Volatile Organic Compounds).

Previously used methods for detecting the actual values required cumbersome sampling from carrier materials or bubbling techniques, followed by analysis in the laboratory using expensive and complex procedures. Additionally, the process of inserting and removing samples was complicated. Online methods working with H2 and flame were and are completely unsuitable in cleanrooms.

The newly developed ONLINE device, the GO-ATC, was created by Gröger & Obst and is a device for real-time online measurement of hydrocarbons in gases. In simpler terms, it is a device for detecting VOCs in the air and can be used directly in the room (intake via hose up to 10m) and only requires electricity.

The detection limit achieved with this device is 1 ppb, and its selective measurement makes the GO-ATC a special feature among mobile, non-laboratory measurement devices.

About the measurement method of the GO-ATC:

The ubiquitous, non-harmful methane component in the air, present at concentrations of 1-5 ppm depending on weather conditions, is selectively detected and considered during measurements with the GO-ATC.

The air drawn into the cleanroom is split inside the GO-ATC into the measurement side (left), where all carbon compounds are thermally converted to CO2, and the comparison side (right), where the cleanroom air is only warmed.

Using a highly precise analyzer, it is then determined whether and how much CO2 is present on the left side compared to the right. High or suddenly rising CO2 levels on the measurement side are a clear indication of contaminated cleanroom air.

The GO-ATC detects all carbon compounds and therefore does not have the disadvantage of sensors limited to only a few substances. Because a VOC, regardless of what substance it is, is a carbon compound. It is converted to CO2, detected, and displayed.

The total parameter provided by the GO-ATC minus the also displayed CH4 value thus gives the actual measured VOC value ONLINE.

Together with the cleanroom specialist MCRT GmbH, GRÖGER & OBST Vertriebs- und Service GmbH conducts VOC measurements in various cleanrooms to verify the DIN ISO 14644-8.1 ACC class or to identify sources of emission. Subsequent possibilities for adsorbing contaminants through the installation of various sorbents can then be examined, suggested, and installed by MCRT.