OTR & WVTR Testing for Stand-Up Pouch Packaging
Oxygen Transmission Rate (OTR) and Water Vapor Transmission Rate (WVTR) are important indicators for evaluating the barrier performance of stand-up pouch packaging. These tests help determine how effectively a pouch protects sensitive products from oxygen and moisture during storage and transportation.
What Is OTR?
OTR measures the amount of oxygen that passes through a packaging material over a specified period under defined testing conditions. It is commonly expressed as cm³/m²/day.
A low OTR indicates better resistance to oxygen transmission. This is particularly important for coffee, tea, nuts, snacks, dried foods, and other products susceptible to oxidation, flavor loss, or quality deterioration.
What Is WVTR?
WVTR measures the quantity of water vapor transmitted through a packaging material under controlled temperature and relative humidity conditions. It is generally expressed as g/m²/day.
A low WVTR indicates stronger moisture protection. This property is especially important for powders, dehydrated foods, spices, pharmaceuticals, and moisture-sensitive products, where moisture absorption can cause caking, loss of texture, or reduced shelf life.
Testing Conditions
OTR and WVTR results are strongly affected by temperature, relative humidity, film thickness, material structure, and test method. Therefore, test conditions should always be recorded when comparing different materials or suppliers.
For laminated stand-up pouches, testing the complete finished pouch can provide more practical information than testing individual films alone because seals, folds, zippers, spouts, and other components may influence overall package performance.
Testing Methods
OTR testing is commonly performed according to ASTM D3985, which evaluates oxygen gas transmission through plastic films and sheeting.
WVTR can be evaluated according to ASTM F1249 or ISO 15106, depending on the equipment and application requirements. The selected method should match the material type and required specification.
Quality Control Requirements
Testing should be performed on representative samples from production batches. Results should be compared with the approved material specification and product shelf-life requirements.
If OTR or WVTR values exceed the specified limits, potential causes may include incorrect material selection, insufficient barrier layers, lamination defects, excessive film damage, or process variation.
References
ASTM D3985 – Standard Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting
ASTM F1249 – Standard Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting
ISO 15106 – Plastics — Film and Sheeting — Determination of Water Vapour Transmission Rate
ISO 11607 – Packaging for Terminally Sterilized Medical Devices
ASTM F88 – Standard Test Method for Seal Strength of Flexible Barrier Materials
