Quantifying Water Vapor Diffusion across Elastomer Pressure Sensor Seals
Water vapor diffusion across elastomer seals causes reference cavity pressurization and dielectric drift, requiring coulometric ISO 15105-2 verification.
ISO 15105-2
Permeation Standard
International testing standards specify instrumental methods for determining the gas transmission rate of plastic film and sheeting using dynamic chromatography. Calibration technicians use iso 15105-2 to measure carrier gas transport across flexible barrier materials. Test procedures quantify barrier effectiveness in high-grade packaging materials under controlled thermal conditions.
Applicability of this standard extends to single-layer or multi-layer polymeric sheet materials under steady-state conditions.
Carrier Gas Method
Gas chromatography detectors measure trace permeant concentrations swept from the lower chamber by continuous carrier gas flow. Conformance with iso 15105-2 requires zero-gas calibration to eliminate baseline signal drift. Test gas flows into the upper chamber while carrier gas sweeps the lower chamber to create a constant partial pressure gradient.
Mass flow controllers regulate carrier gas velocity to maintain repeatable concentration calculations at the detector output. Permeation rates derive from peak area integration compared against calibrated standard gas mixtures. System stabilization requires purging atmospheric gases from chamber cavities prior to starting test gas flow.
Environmental Control
Cell temperature control must maintain stability within zero point one degree Celsius throughout the test cycle. Precise thermal regulation under iso 15105-2 prevents false permeability variations driven by ambient temperature changes. Humidity sensors monitor carrier gas moisture levels to prevent measurement interference.
Leakage Boundary
Seal integrity at specimen chamber joints prevents ambient oxygen ingress during low-rate permeation runs. Measurements under iso 15105-2 fail when seal leakage exceeds detector background resolution limits.