Gasket Material Compatibility Chart for Chemicals

Chemical resistance determines if a gasket maintains its sealing function when exposed to a specific chemical. A gasket that reacts with the media may swell, shrink, soften, harden, crack, or lose mechanical strength, eventually causing leakage or premature failure.

The gasket material compatibility chart is a way to compare different gasket materials on how they perform against different types of chemical elements like acids, bases, oils, fuels, solvents, water, and steam. However, a chart is a starting point rather than a universal approval because compatibility depends on the chemical concentration, temperature, pressure, exposure duration, and other operating conditions.

The following general chart provides a high-level comparison of common gasket materials. Actual chemical resistivity should always be confirmed against the specific chemical and operating conditions with the gasket manufacturer.

Performance will vary widely based on the particular chemical, concentration, temperature, formulation and conditions of exposure.

What Is Gasket Chemical Resistance and Why Does It Matter?

Gasket chemical resistance is the ability of a gasket material to withstand contact with a chemical without experiencing unacceptable physical or chemical degradation. A chemical-resistant gasket should retain the elasticity, compression resistance, dimensional stability, and mechanical strength needed to maintain a reliable seal throughout its intended service conditions.

Chemical-resistant gaskets are important because they are installed between surfaces that contain or transport chemical media. The gasket may shrink, swell, harden, soften, lose strength, or crack if the gasket material is incompatible with the chemical. These changes prevent the gasket from conforming properly to the sealing surfaces and create a path for leakage.

Chemical resistance affects leak prevention, sealing performance, service life, equipment protection, and process reliability. A compatible gasket material is less likely to deteriorate, require premature replacement, or allow chemicals to damage surrounding components through corrosion or contamination. It helps maintain the pressure and containment required by the application. Chemical resistance should be evaluated as a primary part of gasket selection rather than treated as a secondary material characteristic.

How Does Chemical Exposure Affect Gasket Materials?

Chemical exposure alters a gasket’s physical structure and mechanical properties. Depending on the material and chemical, exposure may cause swelling, shrinkage, cracking, softening, hardening, fragility, discoloration, or loss of strength. For example, an incompatible fluid may be absorbed by a rubber gasket, causing it to swell, while another chemical may extract components from the material and cause it to harden or lose elasticity. The ability of a rubber gasket to maintain compression and adapt to the mating surface is reduced, eventually creating a leakage path because of these circumstances.

What Factors Determine a Gasket Material’s Chemical Resistance?

The factors that determine a gasket material’s chemical resistance are listed below.

• Chemical type: Different acids, bases, oils, solvents, oxidizers, and other chemicals react differently with gasket materials.
• Chemical concentration: A material that tolerates a dilute solution may perform differently at higher concentrations.
• Temperature: Elevated temperatures can accelerate chemical reactions and material degradation.
• Exposure time: Continuous exposure generally places greater demands on the material than brief contact.
• Pressure: Pressure can increase mechanical stresses and aggravate deformation or extrusion after chemical exposure.
• Operating conditions: Flow, cycling, compression, thermal changes, and the presence of multiple chemicals can affect performance.
• Material formulation: Two gaskets made from the same base polymer may have different resistance because their formulations and compounds differ.

What Is a Gasket Chemical Compatibility Chart and How Do You Read It?

A gasket chemical compatibility chart compares gasket materials against specific chemicals or chemical groups to indicate whether the material is generally compatible, conditionally suitable, or unsuitable for exposure.

To use a chart, follow these steps below.

1. Identify the chemical being sealed.
2. Find the gasket material in the chart.
3. Check the compatibility rating at the expected concentration and temperature.
4. Review the manufacturer’s notes or limitations.
5. Confirm the rating against the actual application conditions.

A chart may use terms such as “excellent,” “good,” “fair,” “poor,” or “not recommended.” These ratings are comparative rather than universal performance guarantees. The manufacturer’s chemical compatibility data take precedence over a generalized chart for critical applications.

Which Gasket Materials Provide the Best Chemical Resistance?

The best gasket material depends on the chemical and application; no single material resists every chemical. PTFE offers broad resistance to acids, bases, solvents, and aggressive chemicals, while FFKM provides the highest resistance for severe chemical and high-temperature service. FKM is best suited to petroleum oils, fuels, and hydrocarbons but is less suitable for hot water and steam. EPDM performs well with water, steam, acids, alkalis, and aqueous chemicals but poorly with petroleum oils and fuels. NBR/Buna-N is effective with oils, fuels, and petroleum-based fluids. Silicone is useful for water and temperature-sensitive applications but has limited resistance to oils and fuels. Neoprene provides balanced resistance to water, weathering, moderate chemicals, and selected oils. The correct choice must be based on the specific gasket material properties.

How Do PTFE, FKM, EPDM, Buna-N, and Silicone Compare?

The comparison tables for PTFE, FKM, EPDM, Buna-N, and silicone are listed below.

The comparison illustrates why chemical compatibility should be evaluated according to the actual service medium rather than by selecting the material with the broadest-sounding properties. 

When Should You Use FFKM for Highly Aggressive Chemicals?

FFKM is generally required when chemical exposure is severe enough that conventional elastomers may not provide adequate resistance, particularly in high-temperature and demanding industrial applications. It is commonly considered for aggressive chemical processing, semiconductor and high-purity processing, pharmaceutical equipment, specialized industrial systems, and applications involving multiple aggressive chemicals or costly leakage and gasket replacement. FFKM provides a very high level of chemical resistance and can maintain performance under challenging conditions, but it is usually a higher-cost option than conventional elastomers, so its use should be justified by the severity and consequences of the operating environment. 

Which Materials Resist Acids and Bases?

The resistance to a wide range of acids and bases is one of the most important uses for PTFE. FFKM can also be a very good solution in harsh chemical environments. EPDM is especially useful with many aqueous acids and alkalis. A general rating is not enough, though chemical identity and concentration still matter for strong oxidizing acids.

The table illustrates material resistance to acids and bases.

Which Materials Resist Oils, Fuels, and Solvents?

Petroleum oils and fuels, FKM, and NBR are common elastomer choices because their chemical structures provide useful resistance to many hydrocarbon-based fluids.

PTFE provides broader resistance across many solvents and hydrocarbons. FFKM is considered when both solvent resistance and severe operating conditions demand a higher-performance elastomer.

Material selection becomes more complicated when a process contains mixtures of hydrocarbons, aromatic compounds, oxygenated solvents, or other additives.

Which Materials Resist Water, Steam, and Coolants?

EPDM is widely used where resistance to water, hot water, steam, and many aqueous chemicals is required. PTFE also provides broad resistance to water and many chemical solutions.

Silicone can perform well in water-related applications and offers a broad temperature range, but its resistance to oils and fuels is generally weaker than that of FKM or NBR. 

It is better to check the temperature, steam type, pressure, and gasket formulation than rely on the base polymer designation for steam service.

Which Materials Resist Oxidizing Chemicals?

Oxidizing chemicals require particular attention because some elastomers that perform well against acids or bases can deteriorate when exposed to strong oxidizers.

PTFE generally provides strong resistance to many oxidizing chemical environments. FFKM compounds also perform well in highly aggressive chemical applications.

How Do Temperature and Chemical Concentration Affect Gasket Compatibility?

Higher temperatures and chemical concentrations increase the severity of chemical exposure and accelerate material degradation. A gasket that performs well with a dilute chemical at room temperature may not provide the same performance at a higher concentration or operating temperature.

Temperature increases the rate of chemical interaction with the gasket. Concentration changes the chemical environment to which the material is exposed.

How Does Chemical Exposure Time Affect Gasket Performance?

The gasket performance does not place the same demands in short-term contact and continuous chemical exposure.

A gasket material may tolerate brief exposure without noticeable deterioration, while prolonged contact allows the chemical to penetrate, extract components, swell the material, or alter its mechanical properties. Longer exposure accelerates degradation when the material is only marginally compatible with the chemical.

To assess the compatibility for continuous service applications, consider the following.

• Duration of exposure
• Frequency of chemical contact
• Temperature during exposure
• Chemical concentration
• Whether the gasket is continuously compressed
• Expected service life

How Do You Select the Right Gasket Material for a Chemical Application?

To select the right gasket material for a chemical application, follow these steps below.

1. Identify the chemical medium. Determine exactly what fluid, gas, chemical mixture, or process media the gasket will contact.
2. Determine the concentration. Record the chemical concentration rather than relying only on its general chemical category.
3. Determine the operating temperature. Include normal, minimum, maximum, and potential temperature excursions.
4. Determine the pressure and mechanical conditions. Consider pressure, compression, movement, cycling, and potential extrusion.
5. Review compatibility data. Check the manufacturer’s chemical resistance and compatibility information for the specific gasket compound.
6. Compare candidate materials. Eliminate materials with known incompatibilities before considering secondary properties.
7. Evaluate the complete service environment. Consider exposure time, water, steam, cleaning agents, additives, and other chemicals that may contact the gasket.
8. Confirm the selection. For critical applications, obtain manufacturer confirmation or conduct appropriate testing before installation.

Which Gasket Material Is Best for Different Chemical Applications?

The best gasket material depends on the chemical and the operating environment.

No material in the table should be treated as universally suitable. The chemical, concentration, temperature, pressure, and exposure duration must determine the final selection.

Are Chemical Resistance and Chemical Compatibility the Same?

No. Chemical resistance and chemical compatibility are related but not identical.

Chemical resistance describes a material’s ability to withstand exposure to a chemical without unacceptable degradation. Chemical compatibility considers whether that material is suitable for a particular application under its actual operating conditions.

Gasket materials have good resistance to a chemical under room-temperature conditions but become unsuitable when the same chemical is concentrated, heated, pressurized, or continuously present.

Can a Chemically Resistant Gasket Still Fail?

Yes, a chemically resistant gasket can still fail. Chemical resistance only addresses one part of gasket performance. Pressure beyond the material’s mechanical capability, incorrect compression, extrusion, poor flange alignment, installation damage, incompatible mechanical conditions, excessive exposure time, chemical concentrations outside the tested range, or an unsuitable gasket design failure results from excessive temperature. A gasket must be compatible with the complete service environment, not merely the chemical itself. 

How Can You Verify Chemical Compatibility Before Installing a Gasket?

To verify chemical compatibility before installing a gasket, follow the steps below.

1. Identify the exact chemical or chemical mixture.
2. Confirm its concentration.
3. Determine the minimum and maximum operating temperatures.
4. Determine operating pressure and exposure duration.
5. Check the manufacturer’s compatibility chart or technical documentation.
6. Review any limitations or warnings associated with the material.
7. Contact the manufacturer when the application involves unusual chemicals, high temperatures, or critical containment.
8. Use application-specific testing when compatibility cannot be established reliably from available data.

What Are the Common Mistakes When Choosing a Chemical Resistant Gasket?

The common mistakes when choosing chemical-resistant gaskets are listed below.

• Choosing a gasket based only on the chemical name.
• Ignoring chemical concentration.
• Ignoring operating temperature.
• Assuming all grades of the same polymer have identical resistance.
• Selecting an elastomer based on general reputation rather than application data.
• Treating “excellent” compatibility as universal.
• Failing to account for continuous exposure.
• Ignoring pressure and mechanical sealing conditions.
• Assuming water resistance automatically means steam resistance.
• Selecting an oil-resistant material for a chemical that contains solvents or other incompatible components.
• Using a general compatibility chart without checking manufacturer-specific data.

Is PTFE More Chemically Resistant Than Rubber Gaskets?

Yes, PTFE provides broader chemical resistance than most conventional rubber gasket materials.

PTFE gasket is resistant to many acids, bases, solvents, and other aggressive chemicals. Conventional elastomers such as NBR, EPDM, FKM, neoprene, and silicone have more specific chemical strengths and limitations.

However, PTFE is not automatically the best gasket for every application. Mechanical loading, temperature, sealing design, pressure, creep, and installation requirements must also be considered.

Is EPDM Better Than FKM for Chemical Resistance?

No, each is better suited to different chemical environments.

EPDM gaskets generally provide stronger resistance to water, steam, many aqueous chemicals, acids, and alkalis. FKM generally provides stronger resistance to petroleum oils, fuels, and many hydrocarbons.

The choice should be based on the chemical being sealed and its operating conditions rather than on an overall ranking of chemical resistance.

Can One Gasket Material Resist All Chemicals?

No, no gasket material is universally resistant to all chemicals under all operating conditions.

Even materials known for broad chemical resistance have limitations. Chemical concentration, temperature, pressure, exposure duration, and chemical mixtures can change the compatibility result.

The correct approach is to match the gasket material to the specific chemical environment.

Does Higher Chemical Resistance Always Mean Better Gasket Performance?

No, higher chemical resistance does not automatically mean better overall gasket performance.

Gasket materials have excellent chemical resistance but may still be unsuitable because of their mechanical properties, compression behavior, temperature limits, pressure requirements, installation conditions, or cost.

A highly chemically resistant material is unnecessary for a mild application where a lower-cost elastomer provides adequate compatibility and sealing performance in some instances.

The best gasket is not simply the material with the highest chemical resistance. It is the material that provides adequate chemical compatibility, mechanical performance, temperature capability, service life, and sealing reliability for the actual application.