ISO 4080 Rubber and Plastic Hoses and Pipes and Their Fittings - Determination of Gas Permeability

The ISO 4080 “Rubber and plastic hoses and pipes and their fittings – Determination of gas permeability” standard, published by the International Organization for Standardization (ISO), describes three methods for determining gas permeability by measuring the volume of gas emitted from a rubber or plastic hose or pipe section used in gas applications over a specified period of time:

Method 1 is to determine the permeability of the entire wall of the hose or pipe section, excluding end fittings, to the test gas.
Method 2 is to determine the permeability of the hose and fitting interface to the test gas.
Method 3 is for precisely determining the permeability of the entire wall of the hose or pipe section, including the end fittings.

These methods are only valid for gases that are insoluble in water. Although the results for Method 1 and Method 2 are expressed in the same units, the results obtained in the case of unpunctured and punctured hoses designed for the same application will not necessarily be comparable because the specified test times are different and the permeability may therefore vary. Therefore, Method 3 is the preferred method.

For the purposes of this standard, the following definitions apply in addition to the terms and definitions given in ISO 8330:

End fitting: A device attached to the end of a hose or pipe that facilitates connection to equipment forming the hose assembly. If necessary, the end fitting may include a fitted matching piece to facilitate testing.
Permeability: The property of a material to transmit gases and liquids through one surface to another via diffusion and sorption processes. It is unrelated to porosity. Permeability involves the diffusion of molecules called permeants across a membrane or interface. Permeability works through diffusion, where the permeable material moves from a high concentration to a low concentration across the interface. In a pressurized hose, the permeable material can pass from the inside to the outside of the hose, through the hose liner and cap.

The test piece should have the following characteristics:

Method 1: The test piece should be a section of hose or pipe long enough to allow the exposed hose or pipe below the gas collection chute to reach a length of 1 m. The cover of the hose test piece can be punctured.
Method 2: The test piece should be an unpunctured section of hose or pipe with end fittings attached. There should be a free length of 1 m between the fittings. The type of fitting used and the method of securing the fittings to the test piece may affect the results obtained using this method.
Method 3: The test piece should be an unpunctured section of hose with end fittings attached. There should be a free length of 0,5 m between the fittings.

No testing should be performed within 24 hours of production. Prior to testing, test samples must be conditioned for at least 3 hours at the specified temperature and humidity, in accordance with ISO 23529 standard.

Unless otherwise specified in the product standard, the test should be performed at a temperature of 23 degrees plus/minus 2 degrees.

The test gas must be as specified in the product standard.

Unless otherwise specified in the product standard, the test should be performed at a gas pressure of 1 MPa (10 bar).

In short, the ISO 4080 standard provides standardized test methods for measuring how much gas passes through (diffuses) the walls of rubber or plastic hoses, pipes, or complete hose assemblies over a specified period. This is particularly important for hoses used in gas transport applications (e.g., LPG, natural gas, industrial gases, refrigerants, or medical gases) where excessive permeability can lead to safety risks, product loss, environmental problems, or decreased performance.

This standard provides consistent, repeatable testing so that manufacturers, certification bodies, and end-users can reliably compare materials and designs.

This latest update to the standard includes the following amendments:

Complete updating and improvement of gas permeability test procedures.
Changing the header to better reflect the pipes and pipe fittings.
Addition of new terms and definitions

This standard applies to rubber and plastic hoses, pipes, and fittings used in gas applications. It specifies three different test methods for determining the volume of gas passing through the material.

The test typically involves pressurizing the hose/pipe with a test gas (usually air, nitrogen, or a specific gas insoluble in water) and then measuring the volume of gas passing through the wall over time under controlled conditions (such as temperature and pressure).

The main application areas for these tests are as follows:

Automotive fuel and coolant lines
Industrial gas transfer hoses
Welding and cutting equipment
Medical gas delivery systems
LPG/propane distribution hoses
Any application where gas diffusion needs to be restricted to meet safety, efficiency, or legal requirements.

Many national and regional regulations (e.g., for gas appliances, automotive or hazardous materials use) refer to ISO 4080 or equivalent methods when specifying maximum permeability limits. Compliance helps ensure product safety and performance.

The ISO 4080 standard is necessary because gas permeability through rubber or plastic hoses and pipes is a natural physical process that can create serious safety, environmental, economic, and performance issues in many applications. Without a standardized, repeatable method for measuring and comparing permeability, it is impossible to reliably assess whether a hose or fitting is suitable for a specific gas transport task. The main reasons why this standard is necessary are:

Safety risks arising from gas leaks.
Environmental and regulatory compliance.
Product loss and economic impact
Performance and system integrity
The need for fair comparison and quality assurance.

In conclusion, the ISO 4080 standard is important because gas permeability in polymer hoses is not zero; this is a fundamental material property, and uncontrolled or unmeasured permeability can lead to hazardous, costly, or non-compliant situations. This standard is a measurable specification that protects people, equipment, the environment, and budgets.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services compliant with the ISO 4080 standard.