ISO 15106: Plastics - Film and sheeting - Determination of water vapour transmission rate
1. Principles and scope
1.1 Fundamental principles
ISO 15106 is an international standard defining methods for determining the water vapour transmission rate (WVTR) through plastic films and sheets. This multi-part standard covers several technological approaches for measuring water vapour flux. WVTR is a critical parameter for evaluating the performance of packaging materials, particularly in the pharmaceutical, food and electronic sectors where protection against moisture is essential. The standard harmonises international test methods to ensure reproducibility and comparability of results.
1.2 Comparison with other standards
| Standard | Scope | Key characteristics |
|---|---|---|
| ISO 15106 | WVTR measurement (Parts 1-4) | Four methods, varied sensor detection |
| ISO 2528 | Classical gravimetric method | Historical reference, manual weighing |
| ASTM F1249 | Modulated infrared (US) | Equivalent to ISO 15106 Parts 2/4 |
| ASTM E96 | Gravimetric method (US) | Comparable to ISO 2528 |
| ASTM F3299 | Optical method | Alternative detection approach |
2. Role and significance
2.1 Importance for product protection
The water vapour transmission rate is a fundamental parameter for evaluating the capacity of plastic films to protect products sensitive to moisture. ISO 15106 enables packaging material manufacturers to quantify this protection and certify that their products meet customer requirements. Critical WVTR values vary according to application: pharmaceutical blisters require very low transmission, while food packaging allows higher values.
2.2 Impact on quality control
ISO 15106 methods enable regular monitoring of the quality of packaging films in production. Quality laboratories use these methods to validate batch conformity and detect process deviations. International standardisation ensures that results from different laboratories can be compared and recognised by control authorities.
2.3 Value for material end users
WVTR data measured according to ISO 15106 provides end customers and prescribers with reliable technical documentation for selecting appropriate packaging materials. This quantified information enables certification of the stability of the packaged product throughout its shelf life.
3. Test procedures and requirements
3.1 Part 1: Humidity detection sensor
This method uses a capacitive humidity sensor to measure water vapour transmission. The film sample is placed between two chambers at controlled relative humidity, and the sensor measures the change in relative humidity on one side of the film. The method is rapid but requires precise sensor calibration.
3.2 Part 2: Infrared detection sensor
Infrared detection uses an IR sensor to measure energy absorption related to the presence of water vapour. This approach allows continuous and precise measurement, particularly suitable for materials with very low transmission rates. It is a fast and reliable method for pharmaceutical applications.
3.3 Part 3: Electrolytic detection method
This classical method uses an electrolytic sensor (P2O5) that absorbs water vapour and changes electrical conductivity. The increase in electrical current is proportional to water vapour flux. This is a highly sensitive technique, appropriate for very low transmissions.
3.4 Part 4: Modulated infrared sensor
The modulated infrared sensor combines the advantages of IR detection with signal modulation to improve accuracy. This modern approach offers high sensitivity and excellent reproducibility, particularly for films with low transmission.
3.5 Synthetic methods table
| Part | Sensor | Typical range | Test duration |
|---|---|---|---|
| 1 | Capacitive humidity | Medium to high | 12-24 hours |
| 2 | Infrared detection | Low to very low | 8-16 hours |
| 3 | Electrolytic (P2O5) | Very low | 6-24 hours |
| 4 | Modulated infrared | Low to very low | 4-12 hours |
4. Regulatory framework
4.1 Regulatory references
ISO 15106 is published by the ISO (International Organization for Standardization) and recognised internationally as the reference standard for WVTR measurement. In Europe, it is transposed by the CEN (European Committee for Standardisation) and mandatory for declarations of conformity to sectoral directives.
4.2 Regulatory application sectors
Pharmaceutical sector
Blisters and primary packaging for medicines must be tested according to ISO 15106 to guarantee the stability of the pharmaceutical product. WVTR data is mandatory in market authorisation application files.
Food and agro-industry sectors
Packaging films for moisture-sensitive foods (dried fruits, chocolate products, dehydrated products) must provide ISO 15106 data for quality and conformity certifications.
Electronics and sensitive components sector
Packaging for electronic components, semiconductors and electrical devices requires WVTR documentation according to ISO 15106 to ensure reliability of stored products.
Medical devices sector
Sterile packaging and medical devices must comply with WVTR specifications documented according to ISO 15106 to maintain sterility and product integrity.
5. Best practices
5.1 For film and packaging material manufacturers
- Select the appropriate ISO 15106 method according to the expected transmission range of the product
- Use an ISO/IEC 17025 accredited laboratory that regularly practises ISO 15106
- Maintain standardised storage conditions for samples before testing
- Regularly evaluate the reproducibility of results between successive batches
- Validate WVTR data under real conditions of product use
5.2 For packaging material end users
- Require ISO 15106 certifications from film suppliers
- Compare WVTR data from different suppliers to select the best cost/performance ratio
- Validate that certified WVTR values meet the protection needs of the finished product
- Document required WVTR specifications in procurement specifications
- Participate in laboratory audits to verify measurement conformity