Water Vapour Transmission Rate WVTR - (also known as Moisture Transmission Rate MTR; or Moisture Vapour Transmission Rate MVTR)
Water Vapour transmission rate (WVTR), which is also known as Moisture vapour transmission rate (MVTR) and even MVTR is the rate at which water vapour can flow through a material, barrier or substance. It is a measure of the permeability- which is the same measurement but relates to all gases and r vapours through any material or compound barrier.
The two main techniques used to measure WVTR / MTR are: traditional Gravimetric measurements - which have the disadvantage of taking many days or weeks to make a measurement; and Instrumental techniques which are very much faster, sometimes taking as little as 30 minutes to gain an accurate result). Within instrumental techniques there are numerous methods, often based around different sensors and gases. The technique must be matched to the application or results may not be reliable.
Our WVTR' MTR meter is built with a variety of options to suit the customer and their precise requirement. This is achieved at a cost that is easily competitive with mass-produced instruments.
Although the main role of the WVTR / MVTR meter is testing the water vapour permeability of materials, packaging and finished products, it can be optionally be configured for a range of gases including helium, hydrocarbons, oxygen, hydrocarbons. CO2 (carbon dioxide) and any other non toxic gases and vapours.
WVTR, MTVR and other vapour permeability standards
Water vapour permeability :
ISO 9932 - Methods for determination of water vapour transmission rate (WVTR) of sheet materials (paper and board) by dynamic sweep and static gas methods
BS 7406 method A - Water vapour permeability of sheet materials (Paper and Board) by Dynamic Sweep and Static Gas Methods
/ISO 15106 specifies an instrumental method for determining the water vapour transmission rate of plastic film, plastic sheeting and multi-layer structures including plastics, using a humidity detection sensor
TAPPI T557 and ASTM F1249 both with water vapour transmission rate through plastic films and sheeting using a modulated infrared sensor
DIN 53122 - Determination of water vapour transmission (density of moisture flow rate) of plastic films, elastomer films, paper, board and other sheet materials; electrolysis method)
ASTM E96 - Standard Test Methods for Water Vapour Transmission of Materials
ASTM F1249 - 06(2011) Standard Test Method for Water Vapour Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor
JIS Z 0208 - Testing Methods for Determination of the Water Vapour Transmission Rate (WVTT) of Moisture-Proof Packaging Materials (Dish Method)
ASTM D-3985 - Oxygen permeability through Plastic Film and Sheeting
ASTM F-1927 - Oxygen permeability and Permanence at Controlled Relative Humidity Through Barrier Materials Using a Coulometric detector
ASTM F-1307 - Oxygen permeability through Dry Packages Using a Coulometric Sensor
DIN 53380-3 and JIS K 7126 - for Oxygen permeability testing of plastic films
DIN 53380-1- vapour permeability testing - Manometric method for testing of plastic films
ASTM D1434 - vapour permeability testing for Plastic Film and Sheeting
ASTM F2476 - 05 Test Method for the Determination of Carbon Dioxide Gas (CO2) Transmission Rate Through Barrier Materials Using An Infrared Detector
ASTM D1434 - Differential Pressure
- Standard Test Method for Determining Gas Permeability Characteristics of Plastic Film and Sheeting
ISO 15105 -1 Differential pressure method for determination of gas-transmission rate (permeability) of Plastics. Film and sheeting
ISO 7229:1997 -
Rubber- or plastics-coated fabrics -- Measurement of gas permeability through fabrics coated with plastics or rubber
Additional WVTR standards:
BS 2782:820A - Methods of testing plastics. Other properties. Determination of water vapour transmission rate (dish method) - Gravimetric
BS 3177 - Method for determining the permeability to water vapour of flexible sheet materials used for packaging
USP <671> - a series of test methods specific to the functionality and performance of containers and package systems used for solid and liquid dosage forms
For equipment to measure permeability click here
For background information on permeability click here