IRM 901 vs IRM 902 vs IRM 903: Key Differences in Rubber Testing
IRM 901, IRM 902 and IRM 903 are standardized reference oils used to compare the behavior of rubber and elastomers in oil environments. Although they belong to the same reference-oil family, they differ in solvency, aromatic character and the degree of swelling they tend to produce in elastomer compounds.
Why Are IRM Reference Oils Used?
These fluids are not intended to reproduce every real service oil exactly. Their purpose is to provide repeatable laboratory media for comparing elastomer formulations under controlled conditions. Test results depend on the selected fluid as well as temperature, exposure time, specimen geometry and the applicable test method.
For a broader overview, see our guide Testing Fluids and Chemicals Used in the Rubber Industry.
IRM 901
IRM 901 is generally used as the lower-swelling reference profile within the three-fluid series. Its higher-aniline-point and lower-solvency character tends to produce less volume change in many elastomers than IRM 903.
IRM 902
IRM 902 provides an intermediate reference profile between IRM 901 and IRM 903. It is commonly used to compare elastomer formulations under a medium level of oil interaction and provides an important midpoint in comparative laboratory testing.
IRM 903
IRM 903 represents the higher-solvency, higher-swelling end of the three-fluid reference series. In comparative testing it may produce more pronounced changes in elastomer volume and physical properties, helping differentiate compounds intended for demanding oil-contact environments.
Key Difference Between IRM 901, IRM 902 and IRM 903
IRM 901: lower swelling tendency and lower solvency reference profile
IRM 902: intermediate interaction profile between 901 and 903
IRM 903: higher swelling tendency and higher solvency reference profile
All three are designed to provide standardized and repeatable comparison of elastomer response to liquid exposure
How Are Test Results Evaluated?
Depending on the specification, laboratories may compare volume, mass, hardness, tensile strength, elongation and visual surface condition before and after immersion. Acceptance limits should always come from the applicable standard, customer specification or OEM technical requirement.
Relationship to ASTM D471 and ISO 1817
ASTM D471 and ISO 1817 are widely used methods for evaluating changes in rubber properties after exposure to liquids. IRM reference oils may be used where specified by the applicable procedure or customer requirement. Laboratories should always confirm the current edition of the standard and the exact test medium required.
Typical Elastomer Components
O-rings and gaskets
Oil seals and diaphragms
Hydraulic and pneumatic sealing elements
Fuel, oil and coolant hoses
Automotive and heavy-duty rubber parts
Formulation-development and quality-control specimens
How Should the Correct IRM Fluid Be Selected?
Selection should be based on the purpose of the test and the applicable specification. IRM 901, 902 and 903 should not be chosen only as a simple light-medium-heavy scale; the laboratory should use the exact reference fluid required by the test procedure. Batch traceability and conformity to the reference-fluid specification are also important for comparable results.
GataMerk Technical Support
GataMerk Endüstriyel supports customers with IRM 901, IRM 902, IRM 903 and other reference test fluids used in the rubber industry. Explore the Rubber & Elastomer Testing category or visit our Products page for the broader portfolio.
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