ISO 4195:2026

ISO 4195:2026 is an International Standard from ISO for conveyor belts with heat-resistant rubber covers. It specifies requirements and test methods for judging how rubber belt covers change after heat exposure, using hardness, elongation at break and tensile strength as the key properties.

It is intended for conveyor belts with a carryside (top) rubber cover thickness of at least 4 mm, and it is not suitable for light conveyor belts covered by ISO 21183-1.

What does ISO 4195:2026 specify?

ISO 4195:2026 sets out how to assess the relative heat resistance of rubber covers on conveyor belts. It combines performance limits with a test method so that users can compare belts in a consistent way.

The document is organized into six clauses:

• Clause 1 - Scope
• Clause 2 - Normative references
• Clause 3 - Terms and definitions
• Clause 4 - Performance requirements
• Clause 5 - Test method
• Clause 6 - Test report

This structure matters in practice because it separates where the standard applies, what must be met, how to test, and what to record.

What are the key requirements of ISO 4195:2026?

ISO 4195:2026 requires that heat resistance be judged by the change in hardness, elongation at break and tensile strength after exposure to heat. The measured change must stay within the limits given for the belt class in Table 1.

1. Belt classes are tied to test temperature

ISO 4195:2026 classifies belts as Class 1, 2, 3 or 4, based on test temperatures up to 100 °C, 125 °C, 150 °C or 175 °C. The manufacturer should state the class used for conformity assessment.

In practice, this is the starting point for selecting the right test severity for the belt’s intended use.

2. The performance limits are class-dependent

ISO 4195:2026 uses Table 1 to limit how much hardness, elongation at break and tensile strength may change after heat exposure. The table also gives minimum or maximum end values for these properties.

That means a belt is not judged only by one property. A buyer, tester or supplier needs to check all three, because a belt can pass one measure and fail another.

3. The test compares heated and unheated samples

ISO 4195:2026 measures the properties before heat exposure and again after heat exposure, then compares the results. The standard uses the same belt for both sets of measurements.

This matters because the result is a change value, not just an absolute property reading.

4. Heat exposure can be done by Method A or Method B

ISO 4195:2026 gives two exposure methods. Method A uses an air oven for 7 days at the class temperature, and Method B uses the same oven conditions for 14 days. Unless otherwise specified, Method A is the standard testing method.

For users, that means the test duration must be agreed and stated, because it affects the severity of the ageing exposure.

5. Sample preparation and conditioning are controlled

ISO 4195:2026 requires full-thickness samples cut from the centre of the belt, at least 100 mm from the edges. For hardness, the sample may be the belt itself or split cover material; for elongation at break and tensile strength, the covers are split away and prepared to a defined thickness.

The test pieces are conditioned for 24 h in atmosphere D, with atmosphere E used for tropical conditions. In practice, this keeps the test state consistent before measurement.

6. Measurements use other ISO test standards

ISO 4195:2026 refers to ISO 48-2 for hardness and ISO 37 for elongation at break and tensile strength. The oven used for heat exposure conforms to ISO 188.

This means the document relies on established rubber test methods rather than redefining the measurement techniques itself.

What terms does ISO 4195:2026 use?

• IRHD - International Rubber Hardness Degree, the hardness scale used for the cover hardness limits in Table 1.
• Carryside (top) cover - the rubber cover on the carrying side of the belt; the standard applies only when this cover is at least 4 mm thick.
• Class 1 to Class 4 - the resistance classes defined by the test temperatures up to 100 °C, 125 °C, 150 °C and 175 °C.
• Method A - the 7-day heat exposure procedure, used as the standard testing method unless otherwise specified.
• Method B - the 14-day heat exposure procedure for the same class temperatures.
• Atmosphere D - the conditioning atmosphere used for preparing test pieces under ISO 18573.
• Atmosphere E - the tropical conditioning atmosphere referenced for special conditions.

Who uses ISO 4195:2026?

ISO 4195:2026 is used by conveyor belt manufacturers, rubber test laboratories, quality managers, technical buyers and specifiers. It is also relevant to inspection and conformity assessment teams that need to verify heat resistance claims.

In practice, these users apply it when selecting belt classes, preparing test reports, comparing supplier data, or checking whether a belt cover keeps acceptable properties after heat ageing.

What changed in ISO 4195:2026 from the previous edition?

ISO 4195:2026 is the third edition and cancels and replaces ISO 4195:2012. The changes stated for this edition are:

• inclusion of a Class 4 in Table 1 and Clause 5.2
• inclusion of test method B for all four classes
• replacement of atmosphere B with D in 5.3.2.1 and 5.3.2.2 to align with the latest ISO 18573
• addition of atmosphere E for tropical conditions in 5.3.2.1 and 5.3.2.2
• removal of the second paragraph of 4.3.2.2 from ISO 4195:2012
• addition of the note that Method A is the standard testing method unless otherwise specified

Which standards are used with ISO 4195:2026?

ISO 4195:2026 cites these related standards:

• ISO 37 - used for measuring tensile stress-strain properties, including elongation at break and tensile strength
• ISO 48-2 - used for measuring rubber hardness
• ISO 188 - used for accelerated ageing and heat resistance tests, including the oven exposure
• ISO 18573 - used for conveyor belt test atmospheres and conditioning periods
• ISO 23529 - used for general procedures for preparing and conditioning test pieces
• ISO 21183-1 - identifies the light conveyor belts that are outside the scope of ISO 4195:2026

What does the ISO 4195:2026 document contain?

ISO 4195:2026 contains a performance table, a detailed heat exposure procedure, conditioning instructions, property measurement steps, a results calculation step and a test report list. Table 1 gives the permissible variations by class, and Clause 5.3 sets out sample selection, oven exposure, preparation of test pieces and property determination.

Figure 1 illustrates why two measurements, before and after heat exposure, show only change between two points and not the full time path of property change. Clause 6 lists the information that must be recorded in the test report, including the belt identification, class, test piece used, exposure conditions, conditioning details, results and test date.