Overview
ISO 15106-7:2015 - "Plastics - Film and sheeting - Determination of water vapour transmission rate - Part 7: Calcium corrosion method" specifies a laboratory method to measure the water vapour transmission rate (WVTR) of plastic film, plastic sheeting and multi‑layer structures by monitoring calcium degradation caused by exposure to water vapour. The standard describes apparatus, conditioning, test conditions and calculation approaches for rapid WVTR measurement across a wide range of permeabilities.
Key topics and requirements
- Principle: WVTR is determined from the reaction between metallic calcium and water vapour; calcium film properties change as corrosion proceeds.
- Measurement routes: Three normative annexes define measurement techniques:
- Annex A - Optical measurement (spectrophotometer detects change in optical transmission)
- Annex B - Electrical measurement (ohmmeter detects change in conductance/resistance)
- Annex C - Corrosion area evaluation (microscope detects colour/area change)
- Apparatus: Typical equipment includes a vacuum evaporator (for Ca deposition), glovebox (≤40 ppm H2O/O2 for handling), environmental chamber (temperature ±0.5 °C, RH ±3 %), spectrophotometer/ohmmeter/microscope as required.
- Test specimens & conditioning:
- Specimens must be representative, free of defects and larger than the cell transmission area.
- Default sample set is three specimens unless otherwise agreed.
- Conditioning in vacuum or inert atmosphere is required; heating may be used for rapid conditioning where applicable.
- Test conditions: Preferred temperature/RH options are given (e.g., 25 °C / 90 % RH; 40 °C / 90 % RH; 60 °C / 90 % RH; 85 °C / 85 % RH). Other conditions may be agreed between parties.
- Results & reporting: Report the arithmetic mean (rounded to two significant figures) and include test conditions, apparatus, specimen ID, WVTR, specimen thickness, area, conditioning and test date. The standard notes precision is not yet established pending interlaboratory data.
Applications and users
ISO 15106-7 is suited to organisations that need accurate, rapid WVTR data for films and laminates:
- Packaging manufacturers evaluating barrier films for food, pharmaceuticals and moisture‑sensitive goods.
- Materials scientists and R&D teams developing multilayer films, coatings or flexible electronics.
- Quality control and test laboratories performing production verification or comparative permeation testing.
- Converters and spec writers requiring standardized WVTR data for materials selection and specifications.
Practical benefits include sensitive detection of permeation through thin films and multilayer structures, and flexible measurement options (optical, electrical, area) to match lab capabilities.
Related standards
ISO 15106 is a multipart standard for WVTR testing. Related parts include:
- Part 1: Humidity detection sensor
- Part 2: Infrared detection sensor
- Part 3: Electrolytic detection sensor
- Part 4: Gas‑chromatographic detection
- Part 5: Pressure sensor
- Part 6: Atmospheric pressure ionization mass spectrometer
Keywords: ISO 15106-7:2015, WVTR, water vapour transmission rate, calcium corrosion method, plastics film, barrier film testing, environmental chamber, vacuum evaporator.