Mecadi laboratory service
Determining the gas permeability of plastics is a decisive factor in the selection and development of materials. We offer you various methods for determining permeation – including measurement using the so-called carrier gas method (also known as the “purge gas method”).
This procedure is based on the test standards DIN 53380-3 or DIN 53380-S or ISO 2872:1977. In addition to the standard conditions, we offer a wide pressure and temperature range for individual testing.
The test cell consists of two chambers that are separated by the material to be tested (e.g. film/plate) (see schematic diagram below). One chamber is filled with the test gas, e.g. hydrogen (so-called feed side), while a carrier gas, usually air, flows through the opposite chamber. The permeation of the gas through the material leads to an enrichment of the pentrant in the carrier gas flow. By quantitatively analyzing the penetrant in the carrier gas flow, the permeation rate of the material can be calculated if the carrier gas flow rate is known.
Schematic representation of the measurement set-up for determining permeation using the carrier gas method.
The advantages of our service
- Precise measurement results: We offer you accurate measurements of permeation rate/coefficient and diffusion coefficient based on recognized standards such as ISO 15105 or CSA/ANSI CHMC 2:19.
- Flexibility in test conditions: We offer a wide range of test conditions, including variable temperatures (-50 °C to +150 °C) and pressures (up to 1000 bar) to meet the specific requirements of your project.
- Advanced tests: In addition to the standard measurement of permeability, we also offer more advanced tests, such as the determination of diffusion coefficients, gas solubilities (sorption and desorption).
- Individual advice: Our team is on hand to advise you on the best test methods for your specific materials and requirements.
Detection limits and recommendations
The carrier gas-based permeation measurement offers high sensitivity and enables the determination of permeation rates for films / sheets from approx. 3.0E-04 to 3.0 E-03 cm 3 day -1 bar -1 (0.1 to 1 cm3 m-2 day-1 bar-1). The specified rates refer to a partial pressure difference of 100 bar or 10 bar. The specified detection limits may deviate for components / hollow bodies / pipes.
Requirements for your samples
- For a precise measurement, we need your samples in a format that meets the standard requirements (circular cut-outs with a diameter of at least 100 mm, or DIN A4 sheets). For standard measurement, we require samples with a diameter / edge length of at least 90 mm.
- It is important that the sample is representative of the material and has no faults or defects.
- Thickness variation < 5%, roughness r(a) < 20 μm.
- We are happy to determine the thickness of the sample for you in accordance with ISO 4593.
- We offer sample cutting from larger containers by cutting, punching, laser cutting, water jet cutting (external).
- For tissue-containing samples, we offer additional cut-edge masking to prevent false-to-low false results.
- We recommend sending at least three independent samples per test. We usually measure samples with a thickness of 20 µm to 3 mm. Other thicknesses are also possible on request.
Test media
We offer a wide range of different test gases and liquids in order to be able to react flexibly to your request. These include, for example
Standard: Hydrogen,CO2 etc.
Specialties: NH3, H2S, NO, NO2, short-chain alkanes, etc.
Result units
- Permeability per unit area (permeation rate): cm3 m-2 day-1 bar-1
- Additional standardization to sample thickness (permeation coefficient: cm3 mm m-2 day-1 bar-1
- Length-related permeability for pipes: cm3 lfm-1 day-1 bar-1
- Specification cm3 in standard state according to DIN 1343: Gas volume at 273.15 K (0 °C) and 1.01325 bar (1 atm).
Get in touch with us!
Would you like to find out more about our carrier gas-based permeation measurement or request a measurement for your materials? Our team will be happy to discuss all the details and help you with customized solutions. Contact us today to find out more about our services and discuss your specific requirements.
(Related) standards
- DIN 53380-1,
- DIN 53380-2,
- DIN 53380-4: Method for the determination of gas permeability,
- ISO 1399:1983: Elastomers, determination of gas permeability, constant volume test,
- ISO 2872:1977: Elastomers, determination of gas permeability, constant pressure test.
By the way: You can find a complete list of our test methods and services here: https://www.mecadi.com/de/permeationsmessungen/ (more on request)
