Overview
ISO 15106-6:2015 specifies a laboratory method to determine the water vapour transmission rate (WVTR) of plastic film, plastic sheeting and multi‑layer structures using an atmospheric pressure ionization mass spectrometer (APIMS) as the detection sensor. The method provides rapid measurement across a very wide WVTR range (ppt–ppb moisture levels) and reports results in grams per square metre per 24 hours [g/(m²·24 h)].
Key topics and requirements
- Scope: Measurement of WVTR for films, sheets and multi‑layer plastics with an APIMS sensor.
- Principle: A specimen separates a wet and a dry chamber. Carrier gas (e.g., N2 or Ar) sweeps water vapour that permeates to the dry side into the APIMS where water‑derived ions (e.g., H2O+ at m/z 18, H3O+ at m/z 19, H(H2O)+ at m/z 37) are quantified and converted to moisture concentration using a calibration graph.
- Specimens & conditioning:
- Representative, wrinkle‑ and pinhole‑free samples; area larger than cell transmission area.
- Three specimens tested by default.
- Condition specimens at 23 °C ± 2 °C (period as specified for material).
- Apparatus & performance:
- Transmission area typically 5–200 mm diameter.
- Carrier gas flow controllers capable of 500–1 000 ml/min.
- Getter to reduce background moisture below 1 ppb.
- APIMS sensitivity: at least 0.01 parts per billion by volume for water ion species.
- Temperature control of cell within ±0.5 °C.
- Test conditions: Preferred temperatures/humidities include 25 °C/90% RH, 40 °C/90% RH, 60 °C/90% RH and 85 °C/85% RH (other conditions by agreement).
- Calibration: Low‑level humidity standards prepared per ISO 6145‑8 (diffusion method) or equivalent; two‑stage dilution examples described to reach ppt–ppb ranges.
- Calculation: WVTR computed from carrier gas flow, calibrated moisture concentration difference (before/after humidification), specimen area and water molecular weight. Results averaged and rounded to two significant figures.
- Precision: Not yet established - interlaboratory data are pending.
Applications and users
- Who uses it: Packaging engineers, materials scientists, quality control and R&D laboratories, barrier film manufacturers, and test houses evaluating moisture barrier performance.
- Practical uses:
- Comparing barrier performance of films and laminates for food, medical and electronic packaging.
- Rapid, ultra‑sensitive WVTR screening during material development or production control.
- Verifying compliance with product specifications where very low moisture transmission must be quantified.
Related standards
- ISO 15106 (other parts): Part 1 (humidity sensor), Part 2 (infrared), Part 3 (electrolytic), Part 4 (gas‑chromatographic), Part 5 (pressure sensor), Part 7 (calcium corrosion).
- ISO 6145‑8: Preparation of low‑level calibration gas mixtures (diffusion method).
- ISO 4593: Thickness measurement for films and sheeting.
Keywords: ISO 15106-6:2015, WVTR, water vapour transmission rate, atmospheric pressure ionization mass spectrometer, APIMS, plastic film, barrier testing, moisture permeation, packaging materials.
Open preview (PDF)Plastics — Film and sheeting — Determination of water vapour transmission rate — Part 6: Atmospheric pressure ionization mass spectrometer method