Knowledge | Articles of the competence platform STS

Fundamentals of Hygienic Pressure Measurement

Written by STS | Jun 23, 2025 1:24:10 PM

In sensitive areas such as the food and pharmaceutical industries, pressure measurement must meet the highest hygiene standards. What to consider regarding design, materials, and cleanability – and how modular systems from STS excel in this regard.

Hygiene as the top priority

In the food, pharma, and biotech industries, hygiene plays a central role. Pressure transmitters must not only measure precisely but also be constructed so that they do not form germ nests and are easy to clean. They must also comply with regulations such as EHEDG (Europe) and FDA (USA).

Construction: No corners, no edges

Dead spaces, gaps, and sharp edges provide attack surfaces for germs – therefore, hygienic pressure transmitters are designed to be as smooth as possible and without dead zones. The connection is particularly important: Clamp, milking tube, or DIN-flanges allow for quick and hygienic disassembly. Screw threads, on the other hand, are to be avoided.

Material selection: Smooth, robust, resistant

All media-contacting components – membrane, housing, seals – must be corrosion-resistant and smooth. The lower the surface roughness, the lower the risk of microbial colonization. STS uses, for example, stainless steel 1.4404 (V4A) with a surface roughness of ≤ 0.4 μm.

Seals must also be chemically and thermally resistant. STS uses Viton® – a fluoroelastomer that remains stable even at high temperatures. Furthermore, the transmission fluid used must not pose a danger to the medium – silicone oil is therefore prohibited. Instead, approved media by authorities are used.

Cleaning: CIP and SIP focus

Hygienic pressure transmitters must withstand Cleaning in Place (CIP) and Sterilization in Place (SIP) – cleaning with caustic, acids, disinfectants, and steam at 140 °C, without disassembly.

  • CIP: Multi-stage cleaning with water, alkalis, acids, disinfection, & pure water
  • SIP: Steam sterilization at up to 140 °C to kill all germs

Special requirements and additional functions

Some applications additionally require:

  • ATEX certification for explosion-prone zones
  • Readjustable transmitters, e.g., for regular re-calibration in critical processes
  • Combined pressure & temperature measurement, for example, for packaging machines in sterile production

Conclusion: Flexibility through modularity

Every hygienic process has its own requirements – whether in cleaning, temperature, connection, or materials. That is why STS relies on a modular system: pressure transmitters are configured precisely for the application – quickly, safely, and in compliance with standards.