BMW GS 93011 Elastomers

Developed by BMW, a multinational vehicle manufacturer, the “BMW GS 93011 Elastomers” standard consists of the following sub-sections published under the same title:

• The standard “BMW GS 93011-1 Determination of Ignition Residue of Halogen-Free Elastomers (950 degrees)” describes a test method for determining the ignition residue (ignition burn residue or ash content) remaining after high-temperature combustion of halogen-free elastomers. The test is typically performed at 950 degrees. The purpose of this test is material identification and quality control. It helps verify the inorganic filler content or ash residue remaining after the combustion of organic components. Halogen-free elastomers are becoming increasingly important in automotive applications due to environmental regulations, fire safety standards, and recycling requirements. Low residue levels generally indicate purer materials containing fewer inorganic additives, which can affect performance, durability, and compatibility.
• The standard “BMW GS 93011-2 Identification, determination of ignition residue of elastomers containing chlorine, bromine or iodine (950 degrees)” describes a method for determining ignition residue (ash content, combustion residue or ignition residue) in elastomers containing halogens such as chlorine, bromine or iodine. This standard is part of the broader GS 93011 series of standards that provide methods for identifying and characterizing elastomers through thermal decomposition and residue analysis.

This standard targets halogen-containing elastomers (such as chloroprene rubber, chlorinated polyethylene, bromobutyl rubber, or halogenated fluorinated elastomers). Halogens can affect combustion behavior, residue formation, and the potential formation of halogen compounds during combustion. This test helps to:

• To determine the presence and type of halogenated elastomers.
• Measuring the non-volatile inorganic residue (ash) remaining after combustion at high temperatures.
• To support material approval, quality control, and compliance with BMW specifications for parts in vehicles such as gaskets, hoses, seals, vibration isolators, or other rubber components.

Halogenated elastomers are used when oil resistance, flame retardancy, or certain chemical resistance is required, but their use is regulated due to environmental and health concerns (e.g., restrictions on certain halogen compounds).

• The standard “BMW GS 93011-3 Identification, determination of extractable components by extraction method using cyclohexane/acetone” focuses on the determination of extractable components (soluble matter) via solvent extraction. This standard provides a method for determining the amount of elastomer that can be extracted using specific solvents and helps in:
• Determining the type of elastomer or rubber compound.
• To evaluate the content of low molecular weight substances, plasticizers, processing aids, uncured components, or other soluble additives.
• To assess material purity, formulation consistency, and potential migration risks (e.g., substances that may leach over time and affect performance, contact with liquids, or emissions).
• To support supplier qualification, part approval, and quality assurance for rubber parts (e.g., gaskets, O-rings, hoses, bushings, vibration dampers, seals, or air seal strips) in BMW vehicles.

Extractable material testing is crucial in automotive applications where elastomers come into contact with fuels, oils, coolants, or brake fluids, or where long-term stability and low extractable material content are required to prevent swelling, degradation, or contamination.

• The standard “BMW GS 93011-4 Identification, determination of thermal degradation behavior using thermogravimetry (TG)” describes the thermogravimetric analysis (TGA) method used to determine the thermal degradation behavior of elastomers. This standard uses thermogravimetric analysis to monitor mass changes in an elastomer sample heated under controlled conditions. This analysis reveals the following:
• Decomposition temperatures and thermal decay stages.
• Content of volatile components (e.g., moisture, residual solvents, low molecular weight additives).
• Polymer degradation behavior.
• The amount of inorganic fillers, carbon black, or ash residue remaining after decomposition.
• Overall thermal stability and composition profile.

This data helps in the following ways:

• To determine the type or family of elastomer.
• To identify formulation inconsistencies or impurities.
• To verify compliance with BMW specifications in terms of durability, heat resistance and performance in vehicle applications (e.g. engine mounting components, gaskets, hoses, belts, vibration dampers or heat-exposed seals).
• Supporting fault analysis, reverse engineering, or supplier qualification.

TGA is particularly valuable because it provides a fingerprint of the material's thermal behavior and complements residue and extraction tests for more accurate material classification.

• The standard “BMW GS 93011-5 Identification, determination of low temperature guide value by differential scanning calorimetry (DSC)” uses DSC to measure thermal transitions in elastomers, particularly the glass transition temperature (Tg) or other low-temperature phase changes. The cold guide value obtained from this test is used for the following purposes:
• A basic identifier for a type or family of elastomer.
• An indicator of low-temperature flexibility and performance (critical for parts that need to remain functional in cold climates or sub-zero conditions).
• A quality control parameter used to verify formulation consistency, identify unsuitable composition, or confirm suitability for specific vehicle applications.

Elastomers used in the automotive industry (e.g., gaskets, O-rings, hoses, bushings, fasteners, seals, air seal strips, or vibration dampers) are often exposed to extreme cold. In such cases, brittleness or loss of elasticity can lead to leaks, noise, vibration, or failure. The DSC-based cold guidance value helps materials meet BMW's low-temperature requirements.

• The “BMW GS 93011-6 Identification, infrared spectroscopic analysis (IR), pyrolysis IR” standard focuses on infrared spectroscopic analysis (IR) using pyrolysis-IR (pyrolysis infrared spectroscopy). Pyrolysis-IR combines thermal decomposition (pyrolysis) with Fourier transform infrared spectroscopy (FTIR) to analyze the volatile decomposition products (pyrrolysates) released by elastomers when heated in an inert atmosphere. This creates a characteristic IR spectrum (fingerprint) of the gaseous decomposition products, enabling:
• Precise identification of the elastomer type or family.
• Identification of specific polymers, copolymers, or additives that produce unique absorption bands.
• Differentiating between similar materials when other methods (e.g., TGA or ash residue) yield overlapping results.
• Verification of material consistency, detection of contaminants, or verification against reference spectra for quality assurance.

This method is particularly effective for complex or filled elastomers, as pyrolysis evaporates the organic polymer matrix while leaving behind inorganic fillers, and IR captures the molecular structure of the decomposing organics.

• The standard “BMW GS 93011-8 Determination of properties, determination of resistance to stress cracking in plastics on contact with elastomers” describes a method for determining the resistance of plastics to stress cracking (stress crack resistance or environmental stress crack resistance) resulting from contact with elastomers. Many automotive parts combine elastomers (e.g., gaskets, seals, washers, hoses, bushings) with plastic housings, coatings, connectors, or structural elements (e.g., polyamide, polypropylene). Substances migrating from the elastomer (e.g., plasticizers, processing oils, antioxidants, or swelling agents) can act as agents causing stress cracking in the plastic under mechanical stress, heat, or environmental exposure. This leads to:
• Crack formation.
• Brittle cracking.
• Premature failure (e.g., leaks in fuel systems, electrical short circuits, or structural weakness).

This standard ensures the compatibility of elastomer-plastic pairs by measuring the potential for elastomers to cause stress cracking in plastics. It is critical for safety-critical or long-lasting components in engine compartments, interiors and exteriors, or under-hood areas.

• The “BMW GS 93011-9 Specification of properties, effects of temperature, flexural stress under cold conditions” standard specifically addresses the specification of properties under the influence of temperature and focuses on flexural stress under cold conditions (low temperature bending test, cold bending stress or cold bending/flexibility assessment).

While the GS 93011-5 standard determines the intrinsic glass transition temperature (Tg) or cold guide value using DSC, the GS 93011-9 standard evaluates the practical mechanical behavior of the elastomer under cold bending stress. It addresses the following:

• Flexibility when bent at low temperatures and resistance to cracking or brittleness.
• Whether the material remains elastic and functional in cold environments (no fracture, excessive stiffness, or surface damage).
• Suitable for applications where elastomers experience bending or stretching in sub-zero conditions (e.g., door seals, air seal strips, sleeves, hoses, bellows, vibration isolators, or suspension bushings in vehicles operating in winter climates).

This test links thermal characterization (from DSC) to real-world low-temperature performance, ensuring elastomers do not become brittle, crack, or lose sealing effectiveness in cold weather. This is critical for NVH (noise, vibration, harshness), durability, and leak prevention.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its customers, 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 to businesses in accordance with the "BMW GS 93011 Elastomers" standard.