Determination of Cold Resistance According to EN 1109 Standard

Bituminous waterproofing membranes must maintain their durability under various climatic conditions for many years. In cold climates, cracking, breaking, or loss of flexibility during bending can lead to serious waterproofing failures. The membrane flexibility at low temperature test is a standardized method used to determine the flexibility and crack resistance of these materials at low temperatures. This test identifies the minimum temperature at which the product can be safely used without cracking.

EN 1109 / BS EN 1109 / TS EN 1109 Standard

EN 1109, titled “Flexible sheets for waterproofing – Bitumen sheets for roof waterproofing – Determination of flexibility at low temperature,” is the European standard specifying how to evaluate the flexibility of bituminous waterproofing sheets at low temperatures.

  • BS EN 1109: The British version of the European standard.

  • TS EN 1109: The Turkish adaptation, published by the Turkish Standards Institution (TSE).

This standard examines the cracking and breaking behavior of specimens bent at specified low temperatures, providing an objective assessment of the material’s suitability for cold environments.

Test Definition

The membrane flexibility at low temperature test evaluates whether a material maintains flexibility when subjected to low temperatures.
The test principle is summarized as follows:

  1. The sample is cooled to a specified temperature.

  2. It is bent at a constant speed around a mandrel of a defined diameter.

  3. The specimen is visually examined for cracks or fractures.

  4. The lowest temperature at which no cracking occurs is recorded as the minimum bending temperature.

Test Equipment

  • Cooling chamber or cooling bath: To bring the specimen to the required temperature.

  • Bending apparatus: Contains mandrels of different diameters according to the standard.

  • Thermometer: To measure the exact temperature of the specimen.

  • Timer: To ensure the specimen remains at the target temperature for the specified period.

Test Procedure

  1. Sample Preparation
    The bituminous membrane is cut into specific dimensions, either parallel or perpendicular to the production direction.

  2. Cooling
    The specimen is conditioned at the target low temperature for at least one hour.

  3. Bending Operation
    The cooled specimen is bent at a constant speed around a mandrel of defined diameter.

  4. Observation
    The specimen is visually inspected for cracks, breaks, or other defects.

  5. Result Evaluation
    The lowest temperature at which no cracking occurs is reported as the minimum bending temperature.

Evaluation of Results

  • Pass: No cracking or breaking observed.

  • Fail: Cracks or fractures observed on the surface.
    Test reports should include:

  • Sample identification and properties

  • Test temperature

  • Mandrel diameter

  • Observed results

  • Date and laboratory details

Applications and Importance

The membrane flexibility at low temperature test is crucial in the following applications:

  • Roof waterproofing systems

  • Underground waterproofing

  • Bridge and viaduct coatings

  • Pavement materials used in cold climates

The test is particularly important when selecting materials for cold regions. Non-compliant membranes pose a high risk of cracking and structural failure, which can compromise the integrity of the entire waterproofing system.

Advantages and Limitations

Advantages

  • Simulates real environmental conditions.

  • Reliable criterion for quality control and certification.

  • Provides objective data for material comparison.

Limitations

  • Does not represent all long-term aging effects.

  • Should be combined with other mechanical and chemical tests.

  • Reflects short-term performance rather than full life expectancy.

Conclusion

The membrane flexibility at low temperature test is a critical method for assessing the durability and flexibility of bituminous membranes under cold conditions. Conducted according to the EN 1109 standard, it ensures that materials are suitable for their intended climatic applications. Compliance with EN 1109 provides manufacturers and users with confidence in product performance and facilitates international market acceptance. For projects in cold climates, membranes that pass this test offer long-term reliability and durability.

Frequently Asked Questions (FAQ)

1. On which materials is the membrane flexibility at low temperature test performed?
It is generally applied to bituminous waterproofing membranes and roofing sheets.

2. At what temperatures is the EN 1109 test performed?
The test is typically conducted at temperatures between -5°C and -30°C, depending on product requirements.

3. What conditions cause a test to fail?
Any visible cracking, breakage, or deformation during bending indicates test failure.

4. In which industries is this test mandatory?
It is widely required in the construction, roofing, infrastructure, and waterproofing industries.

5. How long does the test take?
Including preparation and cooling, the test generally takes between 1 and 2 hours.