ISO 80369-20

Purpose of the tests
Small-bore connectors are used in a wide variety of medical applications to transfer liquids or gases between components. Reliable connection is important both for maintaining the intended fluid path and for preventing unintended separation or leakage.
ISO 80369-20 provides standardized procedures for evaluating these functional characteristics under reproducible laboratory conditions.
The methods are intended as type tests using representative samples of the connector design. They can therefore be used to demonstrate whether a connector, as designed and manufactured, meets the performance requirements specified in the relevant application standard.

Leakage testing
Several test methods are available to evaluate the sealing performance of a connector under different operating conditions.
For positive-pressure testing, the connection can be evaluated either by monitoring the change in air pressure over a defined period or by pressurizing the connection with water and checking for visible liquid leakage.
For applications involving aspiration or negative pressure, the connector can be tested under subatmospheric pressure. The pressure change over time can be measured to identify leakage. An alternative method uses water and visual observation of air bubbles during aspiration.
The relevant application standard defines which leakage method is appropriate as well as the required pressure, test duration and acceptance criterion.

Mechanical connection security
ISO 80369-20 also provides methods for evaluating whether an assembled connector remains securely connected when exposed to mechanical loads.
Depending on the connector design, testing can assess resistance to:

• axial separation
• separation caused by unscrewing
• overriding of the locking mechanism

For axial separation testing, the assembled connector is subjected to a defined tensile load and the sealing interface is checked to confirm that it remains connected.
For locking connectors, rotational tests can be used to determine whether the connection remains secure when an unscrewing torque is applied and whether the locking elements resist overriding.

Stress cracking
The stress cracking test evaluates whether a connector maintains its sealing function after remaining assembled under defined conditions.
The connector is assembled to an appropriate reference connector and kept in the connected condition for a specified period. Its sealing performance is then verified using the leakage test defined by the relevant application standard.
This method is particularly relevant for connector materials and designs where stresses introduced during assembly could affect the long-term integrity of the connection.

Disconnection by unscrewing
Some connectors are intended to be connected and disconnected repeatedly during normal use. ISO 80369-20 therefore includes a method for evaluating whether such connectors can still be intentionally disconnected.
After controlled assembly, an increasing unscrewing torque is applied until the connection begins to loosen and separates. The peak torque is measured and compared with the requirement defined by the relevant application-specific standard.
This test complements the connection-security tests by assessing not only whether a connection remains secure during use, but also whether it can be deliberately disconnected when required.

Test conditions and connector assembly
For the different test methods, the connector under test is generally assembled with an appropriate reference connector specified by the relevant application standard.
The standard defines controlled assembly procedures for both locking and non-locking connectors so that the connection is prepared reproducibly before testing.
For materials whose properties can be influenced by moisture, preconditioning is also specified. Environmental conditions during testing are controlled to support repeatable and comparable results.

Evaluation
The evaluation depends on the individual test method and the requirements of the relevant application-specific standard.
Depending on the test, the result may include pressure change, presence or absence of leakage, separation of the connector, resistance to overriding or the torque required for disconnection.
Many of the standard methods are designed as pass/fail tests. ISO 80369-20 also provides options for modifying selected procedures to generate numerical variable data, for example the actual separation force or pressure change, which can then be used for statistical evaluation.
Together, these test methods provide a standardized framework for evaluating the functional integrity of small-bore connector systems under the conditions relevant to their intended application.