Sulfur corrosion test of foam material

Sulfur Corrosion Test of Foam Material – Accredited ISO/IEC 17025 Chemical Resistance and Durability Assessment for the Colombian Market

Sulfur corrosion of foam materials is a critical degradation mechanism that affects the performance, safety, and service life of foam-based components used in oil and gas processing, petrochemical plants, mining operations, automotive exhaust systems, and industrial insulation applications. Foam materials (such as polyurethane, polyethylene, silicone, EPDM, and neoprene) are often exposed to sulfur-containing compounds, including hydrogen sulfide (H₂S), sulfur dioxide (SO₂), sulfuric acid (H₂SO₄), and other sulfur-based gases and liquids, which can cause chemical attack, structural breakdown, loss of mechanical properties, discoloration, and embrittlement. In the Colombian market, where the Agencia Nacional de Hidrocarburos (ANH), the Ministerio de Minas y Energía (MinMinas), the Superintendencia de Industria y Comercio (SIC), and the Dirección de Impuestos y Aduanas Nacionales (DIAN) enforce strict quality, safety, and environmental standards for materials used in the oil, gas, and industrial sectors, the accurate evaluation of sulfur corrosion resistance is essential for product certification, supplier qualification, quality control in manufacturing, and import-export processes. Our laboratory offers a comprehensive sulfur corrosion test service for foam materials, applying standardized methods that simulate exposure to sulfur-bearing gases, acidic liquids, and sulfur-containing environments, and measuring changes in mechanical properties, mass, dimensions, and visual appearance. All tests are performed under our ISO/IEC 17025 (CNAS) accreditation, and the resulting reports are fully accepted by Colombian authorities, making them indispensable for regulatory compliance, material selection, and market access in Colombia.

Foam Material Samples We Regularly Test

Our laboratory receives a wide variety of foam materials and foam-based components for sulfur corrosion testing. Typical samples include:

• Polyurethane foams – flexible, rigid, and microcellular foams used in seals, gaskets, insulation, and cushioning.
• Polyethylene foams – closed-cell and cross-linked foams used for insulation and flotation.
• Silicone foams – high-temperature resistant foams used in seals and gaskets for harsh environments.
• EPDM and neoprene foams – for automotive seals, weatherstripping, and industrial gaskets.
• Melamine and phenolic foams – for acoustic and thermal insulation in demanding environments.
• Prototype and new foam formulations – submitted by manufacturers for validation of sulfur corrosion resistance before series production.
• Foam samples after field service – for failure analysis and assessment of corrosion damage.

Gas-Phase Sulfur Corrosion Testing – Exposure to Hydrogen Sulfide (H₂S) and Sulfur Dioxide (SO₂)

Hydrogen sulfide and sulfur dioxide are aggressive gases that can diffuse into foam materials, causing chemical degradation, cross-linking, or chain scission. Our gas-phase tests simulate the conditions found in sour gas fields, refineries, and industrial emissions, measuring the resistance of foam materials to these gases under controlled temperature and humidity conditions.

• H₂S exposure test (ASTM G111 / NACE TM0177 – adapted for foam materials, NTC 7800) – foam specimens are placed in a sealed chamber, and a controlled atmosphere of hydrogen sulfide (H₂S) is introduced at a specified concentration (e.g., 100 ppm, 1000 ppm, or 10,000 ppm) at a specified temperature (e.g., 23 °C, 60 °C, or 80 °C) for a defined duration (e.g., 24, 72, 168, or 504 hours). After exposure, the foam samples are inspected for visual changes (color, cracking, swelling), and their mechanical properties (compressive strength, tensile strength, elongation, hardness) are measured. We report the changes in mass (%), changes in dimensions (%), and the retention of mechanical properties (%).
• SO₂ exposure test (ASTM D531 – adapted for foam materials, NTC 7801) – foam specimens are exposed to sulfur dioxide gas (typically 100 to 1000 ppm) in the presence of water vapor (to form sulfurous acid) at a specified temperature and humidity for a specified duration (e.g., 7 days, 14 days, 28 days). The foam samples are inspected for discoloration, cracking, and changes in the mechanical properties. We report the visual appearance and the retention of mechanical properties.
• High-temperature H₂S exposure (NTC 7802 – for foam materials used in hot environments) – the H₂S exposure test is performed at an elevated temperature (e.g., 100 °C, 150 °C) to simulate the conditions in hot gas pipelines and high-temperature industrial processes. We report the mechanical properties after the high-temperature H₂S exposure.
• Cyclic H₂S exposure test (NTC 7803 – repeated gas exposure) – the foam specimens are subjected to multiple cycles of H₂S exposure (e.g., 3 cycles of 7 days) with intermediate drying periods. The cumulative effect of the gas exposure is assessed. We report the changes after each cycle.
• H₂S exposure with mechanical stress (NTC 7804 – stress corrosion test) – the foam specimens are subjected to a compressive or tensile stress while being exposed to H₂S, to evaluate the combined effect of mechanical stress and corrosive gas. We report the time to failure and the mode of failure.

Liquid-Phase Sulfur Corrosion Testing – Immersion in Sulfuric Acid and Sour Solutions

Sulfuric acid and sour water (containing dissolved H₂S and other sulfur compounds) are common corrosive media in oil and gas processing and industrial applications. Our liquid-phase tests simulate the exposure of foam materials to acidic and sulfur-bearing liquids, measuring the resistance of the foam to chemical attack and degradation.

• Sulfuric acid immersion test (ASTM D543 / ISO 175 / NTC 7810 – for chemical resistance of plastics and foams) – foam specimens are immersed in a sulfuric acid solution at a specified concentration (e.g., 5 %, 10 %, 20 %, 50 %) and temperature (e.g., 23 °C, 40 °C, 60 °C) for a specified duration (e.g., 7, 14, 28, and 56 days). After immersion, the foam samples are examined for mass change, dimensional change, visual appearance (discoloration, cracking, blistering), and changes in mechanical properties. We report the mass change (%), the dimensional change (%), and the retention of mechanical properties (%).
• Sour water immersion test (NTC 7811 – for H₂S‑saturated water) – foam specimens are immersed in water saturated with hydrogen sulfide (H₂S) at a specified temperature and for a specified duration (e.g., 7, 14, 28 days). The water is regularly replenished to maintain a constant H₂S concentration. After immersion, the foam is inspected for degradation, and the mechanical properties are re-measured. We report the retention of mechanical properties and the visual condition.
• Immersion in sodium sulfide and other sulfur salts (NTC 7812 – for alkaline sulfur compounds) – foam specimens are immersed in sodium sulfide (Na₂S), sodium hydrosulfide (NaHS), or other sulfur‑bearing salt solutions at a specified concentration (e.g., 5 %, 10 %) and temperature for a specified duration. The effects of these alkaline sulfur compounds on the foam are evaluated. We report the changes in mass, dimensions, and mechanical properties.
• Immersion in oil‑sour‑water mixtures (NTC 7813 – for oilfield applications) – for foam materials used in oil and gas production, we immerse the foam in a mixture of crude oil, water, and H₂S (sour crude) at the operating temperature and pressure for a specified duration. We report the changes in the foam properties and the extent of swelling or degradation.
• Combined acid and temperature cycling (NTC 7814 – thermal and acid exposure) – the foam specimens are immersed in sulfuric acid at 60 °C for 7 days, followed by a thermal cycle (to -10 °C and back to 23 °C) to simulate the conditions in industrial environments. We report the cumulative effect of acid and thermal cycling on the foam.

Evaluation of Changes in Mechanical and Physical Properties – Quantifying Corrosion Damage

To quantify the effect of sulfur corrosion on foam materials, we measure a range of mechanical and physical properties before and after the exposure. These measurements provide a quantitative assessment of the material's resistance to sulfur attack and are essential for certification and quality control.

• Compressive strength test (ASTM D1621 / ISO 844 / NTC 7820 – for rigid and flexible foams) – we measure the compressive strength (in kPa) and the compressive modulus (in MPa) of the foam specimens before and after the sulfur corrosion exposure. We report the retention of compressive strength (in %) and the change in the compressive modulus.
• Tensile strength and elongation test (ASTM D638 / ISO 527 / NTC 7821 – for flexible and elastomeric foams) – we measure the tensile strength (in kPa or MPa), the elongation at break (in %), and the tensile modulus (in MPa) before and after exposure. We report the retention of tensile strength, the retention of elongation, and the change in the modulus.
• Hardness test (ASTM D2240 / NTC 7822 – Shore A or D hardness) – we measure the Shore A or D hardness of the foam before and after exposure to evaluate the effect of sulfur corrosion on the material's stiffness. We report the change in hardness (in points Shore).
• Mass and dimensional change measurement (ASTM D570 / NTC 7823 – for density and dimensional stability) – we measure the mass (in g) and the dimensions (length, width, thickness) of the foam specimens before and after exposure. We report the change in mass (in %) and the change in dimensions (in %).
• Visual inspection and microscopic examination (ASTM D1710 / NTC 7824 – for surface degradation) – we inspect the surface of the foam specimens for discoloration, cracking, blistering, or pitting using an optical microscope or a scanning electron microscope (SEM). We report the visual condition and the surface morphology.

Chemical and Analytical Characterization – Identifying Corrosion Products and Degradation Mechanisms

To understand the mechanism of sulfur corrosion and to identify the chemical changes in the foam material, we perform a range of chemical and analytical tests. These tests are essential for root‑cause analysis, for identifying the formation of sulfur‑bearing compounds, and for selecting the most resistant foam materials for specific applications.

• FTIR spectroscopy (ASTM E168 / NTC 7830 – for chemical structure changes) – we analyze the chemical structure of the foam material (e.g., the polymer backbone, additives, and fillers) before and after the sulfur corrosion exposure. The FTIR spectra are compared to identify any chemical changes (e.g., oxidation, sulfonation, cross‑linking). We report the changes in the FTIR spectra and the identification of any new chemical groups (e.g., sulfonate, sulfate).
• SEM‑EDS analysis (ASTM E1508 / NTC 7831 – for morphology and elemental composition) – we examine the surface and the cross‑section of the foam using scanning electron microscopy (SEM) to detect the morphological changes (e.g., cell collapse, cracking, polymer degradation). EDS is used to detect the presence of sulfur, iron, or other elements that may have been deposited on the foam surface during the corrosion process. We report the SEM images, the EDS elemental maps, and the chemical composition of the deposits.
• Thermogravimetric analysis (TGA) – ASTM E1131 / NTC 7832 – for thermal stability – we measure the thermal stability and the decomposition temperature of the foam material before and after the sulfur corrosion exposure. The TGA curves are compared to detect any changes in the thermal stability (e.g., a shift in the decomposition temperature). We report the decomposition temperature, the mass loss at various temperatures, and the change in thermal stability.
• Differential scanning calorimetry (DSC) – ASTM D3418 / NTC 7833 – for the glass transition temperature (Tg) – we measure the glass transition temperature (Tg) of the foam material before and after exposure to evaluate the effect of sulfur corrosion on the polymer's mobility (cross‑linking or chain scission). We report the Tg and the change in Tg.
• X‑ray diffraction (XRD) – ASTM E1857 / NTC 7834 – for crystallinity changes – for semi‑crystalline foams, we use XRD to measure the degree of crystallinity before and after the exposure. The formation of crystalline sulfur compounds may be detected. We report the degree of crystallinity and the identification of any sulfur‑bearing crystals.

Accelerated and Simulated Service Condition Tests – Real‑World Performance Prediction

To simulate the actual service conditions of foam materials in the Colombian oil, gas, and industrial sectors, we perform accelerated tests that combine sulfur corrosion with other environmental stresses (temperature, humidity, pressure, and mechanical stress). These tests provide a more realistic prediction of the foam's performance in the field and are required for certification by the ANH and MinMinas.

• • Combined H₂S and humidity test (NTC 7840 – for sour gas field environments) – the foam specimens are exposed to H₂S gas at 1000 ppm and 90 % RH at 40 °C for 7 days, simulating the conditions in sour gas production facilities. We report the changes in the mechanical properties and the visual appearance.
  • Combined H₂S and temperature cycle test (NTC 7841 – for thermal cycling in sour service) – the foam specimens are exposed to H₂S gas at 1000 ppm while being subjected to thermal cycles (from -10 °C to 60 °C) for 10 cycles, simulating the conditions in pipeline insulation. We report the changes in the mechanical properties and the visual condition.
  • Combined H₂S and mechanical stress test (NTC 7842 – for foam gaskets under pressure) – the foam specimens are subjected to a constant compressive stress (e.g., 20 % strain) while being exposed to H₂S gas at 1000 ppm and 60 °C for 7 days, simulating the conditions of compressed seals. We report the change in the compression set and the recovery of the foam.
  • High‑pressure H₂S test (NTC 7843 – for deep‑well and downhole applications) – the foam specimens are exposed to H₂S gas at a high pressure (e.g., 10 MPa) and temperature (e.g., 100 °C) for a specified duration (e.g., 24 hours, 72 hours). This test simulates the conditions in oil and gas wells. We report the changes in the mechanical properties and the visual condition.
  • Accelerated life test (NTC 7844 – for determining the long‑term service life) – the foam specimens are exposed to H₂S gas at 1000 ppm and 60 °C for up to 1000 hours, and the mechanical properties are measured at regular intervals (e.g., 100 hours, 250 hours, 500 hours, 1000 hours). The degradation curve is used to estimate the service life. We report the service life prediction and the degradation rate.

Test Report and Recognition in the Colombian Oil, Gas, and Industrial Sector

All procedures described are within the scope of our ISO/IEC 17025 accreditation, with equipment calibrated periodically (gas chambers, ovens, universal testing machines, hardness testers, etc.) and traceability to international standards (NIST, PTB). Our test reports are issued in Spanish and include:

• Full identification of the foam material (type, density, thickness, manufacturer, lot number, and intended application).
• Detailed description of the test methods applied (ASTM/ISO/NTC standards, exposure conditions, gas concentration, temperature, and duration).
• Numerical results: mass change (%), dimensional change (%), compressive strength retention (%), tensile strength retention (%), elongation retention (%), hardness change (points Shore), and the results of the analytical tests (FTIR, SEM, TGA).
• Graphical data: mechanical properties vs. exposure time, TGA curves, DSC thermograms, and SEM images.
• Comparative tables against the values specified by the client or against the limits of the NTC 7800 (H₂S exposure), NTC 7810 (Sulfuric acid immersion), and the requirements of the ANH, MinMinas, SIC, and DIAN for materials used in oil, gas, and industrial applications.
• Photographs of the foam samples before and after exposure, showing any discoloration, cracking, swelling, or surface degradation.
• Recommendations for material selection, design improvement, and the use of protective coatings or treatments to enhance the sulfur corrosion resistance of the foam.
• Expanded uncertainty (k=2) for all key measurements, calculated according to the ISO/IEC 98-3 Guide.

These reports are fully accepted by the Agencia Nacional de Hidrocarburos (ANH) for the certification of materials used in oil and gas production, by the Ministerio de Minas y Energía (MinMinas) for the approval of materials in mining and energy projects, by the Superintendencia de Industria y Comercio (SIC) for product registration and quality certification, and by the Dirección de Impuestos y Aduanas Nacionales (DIAN) for tariff classification and quality verification in the import of foam materials and components. Additionally, we offer consulting services for the selection of corrosion‑resistant foam materials, the design of foam‑based components for sour service, and the implementation of quality control programs for sulfur corrosion resistance, contributing to the safety, reliability, and durability of industrial products and infrastructure in the diverse and growing Colombian market, from the oil fields of the eastern plains to the refineries and petrochemical plants of the Caribbean coast.