7 Factors to Consider When Selecting Gaskets for Pharmaceutical Processing Equipment
Gaskets used in pharmaceutical processing equipment have to do more than create a reliable seal. Depending on the application, they may be exposed to aggressive process media, repeated cleaning and sterilization cycles, elevated temperatures, pressure changes, and strict contamination-control requirements.
This combination makes gasket selection particularly important. A material may offer excellent chemical resistance but perform poorly under repeated steam sterilization. Another may withstand the operating temperature but be unsuitable for product contact or the cleaning chemicals used between batches.
Selecting the right gasket requires looking at the complete operating environment rather than any single material property. Understanding the factors that influence gasket performance can help pharmaceutical manufacturers reduce premature failures, maintain reliable seals, and select materials better suited to their equipment and processes.
In this article:
- Regulatory and material requirements
- Chemical compatibility
- Operating temperature and pressure
- CIP and SIP exposure
- Hygiene and contamination control
- Compression and long-term sealing performance
- Equipment and application requirements
- Choosing the right gasket for the application
- Conclusion
1. Regulatory and Material Requirements
For pharmaceutical manufacturers operating in Canada, Health Canada’s Good Manufacturing Practices (GMP) requirements form part of the regulatory framework governing drug manufacturing and quality. Manufacturers supplying equipment or products for the U.S. market may also need to consider applicable FDA current Good Manufacturing Practice requirements, including requirements for product-contact equipment surfaces.
Depending on the application, specifications may also reference United States Pharmacopeia (USP) biological reactivity testing, including USP Class VI where required, industry standards such as ASME Bioprocessing Equipment (BPE), or customer-specific material and documentation requirements.
These requirements are not interchangeable. Terms such as FDA compliant, USP Class VI, sanitary, hygienic, and pharmaceutical grade do not all mean the same thing, and meeting one requirement does not automatically make a gasket suitable for every pharmaceutical application.
Documentation should therefore be reviewed for the specific gasket material or compound being supplied, with consideration given to the equipment, process, product contact, cleaning procedures, and destination market.
2. Chemical Compatibility
A gasket must be compatible with everything it encounters during operation, not simply the primary product being processed.
Pharmaceutical equipment may be exposed to active ingredients, solvents, acids, bases, purified water, oils, and other process media. The same gasket may also encounter aggressive cleaning and sanitizing chemicals between production cycles.
Exposure to incompatible chemicals can cause a gasket to swell, soften, harden, crack, or lose its sealing properties. Even relatively small changes in the material can affect gasket dimensions and the integrity of the seal.
PTFE, for example, offers broad chemical resistance and low reactivity, making it useful in many aggressive chemical applications. EPDM performs well with hot water, steam, and many aqueous solutions, while Viton™ (FKM) may be considered where resistance to certain chemicals, oils, solvents, and elevated temperatures is required.
The general material family is only the starting point. Specific compounds and formulations can perform differently, so compatibility should be confirmed for the actual process media, concentrations, temperatures, and exposure times involved.
3. Operating Temperature and Pressure
Temperature and pressure directly affect how a gasket behaves once equipment is operating.
Elevated temperatures can soften, harden, or accelerate the ageing of some gasket materials. They can also increase creep, compression set, and other forms of permanent deformation that reduce sealing performance over time.
Pressure places additional demands on the gasket and joint. The gasket must maintain sufficient sealing force to contain the process without excessive deformation, extrusion, or loss of compression.
These conditions should be considered together rather than independently. A material capable of handling a particular temperature under one set of conditions may behave differently when exposed to that temperature while also subjected to pressure, chemicals, and repeated cycling.
The highest temperature or pressure rating on a material data sheet therefore should not be the only basis for selection. The complete service environment determines whether the material is appropriate.
4. CIP and SIP Exposure
Cleaning-in-place (CIP) and sterilization-in-place (SIP) procedures create an additional operating environment that the gasket must survive.
During CIP, sealing materials may repeatedly encounter hot water, caustic solutions, acids, sanitizing agents, or other cleaning chemicals. SIP processes can subject the same gasket to repeated cycles of high-temperature steam.
A gasket that is compatible with the pharmaceutical product may therefore still fail prematurely if its response to cleaning and sterilization has not been considered.
Repeated CIP and SIP cycles can contribute to:
- Swelling or shrinkage
- Hardening or softening
- Loss of elasticity
- Compression set
- Chemical degradation
- Thermal ageing
- Reduced sealing performance
When selecting a gasket for equipment undergoing CIP or SIP, manufacturers should consider the cleaning chemicals, concentrations, temperatures, cycle duration, frequency, and steam exposure expected throughout the gasket's service life.
In other words, the cleaning process is part of the application and should be considered during material selection.
5. Hygiene and Contamination Control
In pharmaceutical processing, preventing a leak may be only one requirement of a successful gasket. Gaskets installed in product-contact or hygienic areas should support the intended equipment design without creating unnecessary spaces where residue or contaminants can accumulate.
Material deterioration can also become a concern. A gasket that swells, cracks, extrudes, or begins to break down may affect both sealing performance and the cleanliness of the process.
Correct gasket dimensions are particularly important in hygienic connections. A gasket that is too large, too small, or improperly compressed can alter the geometry of the joint and create areas that are more difficult to clean effectively.
For this reason, contamination control depends not only on selecting a suitable material but also on proper gasket design, fabrication, installation, and maintenance.
6. Compression and Long-Term Sealing Performance
A gasket's performance on the day it is installed does not necessarily indicate how it will perform after months of service.
Over time, gasket materials can experience creep, stress relaxation, compression set, or other permanent changes while subjected to sustained load, temperature, and repeated operating cycles. As the gasket changes, the sealing force within the joint can decrease.
Different materials respond differently to these conditions. Virgin PTFE, for example, offers excellent chemical resistance but is more susceptible to creep under sustained compression. Filled or modified PTFE formulations may provide improved dimensional stability where greater creep resistance is required.
Elastomeric materials such as EPDM, silicone, and Viton™ (FKM) have their own compression-set characteristics that vary according to compound, temperature, and exposure.
Long-term performance should therefore be considered alongside initial sealing ability. If a gasket repeatedly begins leaking, loses elasticity, or permanently deforms after a predictable period of service, the material or operating conditions may need to be reassessed.
7. Equipment and Application Requirements
Even a gasket material that meets the chemical, temperature, and regulatory requirements of an application still needs to work within the equipment itself.
Flange or connection design, gasket dimensions, available compression, surface condition, fastening method, equipment movement, and maintenance practices can all influence sealing performance.
The expected service interval should also be considered. A gasket used in equipment that is routinely disassembled may have different requirements from one expected to remain in service through thousands of operating and cleaning cycles.
This is why there is no universal best gasket for pharmaceutical processing. The right solution depends on the combination of material requirements and the mechanical conditions of the specific equipment.
Understanding the complete application before specifying the gasket can help prevent a technically suitable material from becoming an unsuitable sealing solution.
Choosing the Right Gasket for the Application
Selecting a gasket for pharmaceutical processing requires balancing chemical compatibility, temperature and pressure resistance, cleaning and sterilization exposure, hygienic requirements, mechanical performance, documentation, and expected service life.
The specific material and compound matter, but so do the equipment and conditions in which the gasket will operate. A material that performs exceptionally well in one pharmaceutical application may not provide the same results in another.
When application requirements are not straightforward, working with an experienced gasket manufacturer or material specialist can help identify a sealing solution that meets both the processing requirements and the mechanical demands of the equipment.
Conclusion
Gasket selection for pharmaceutical processing equipment should never be based on a single material property. A gasket must continue to provide a reliable seal while being exposed to the complete combination of process media, temperature, pressure, cleaning and sterilization procedures, compression, and any applicable material or hygienic requirements.
Evaluating these seven factors before selecting a gasket can help reduce premature failures, improve equipment reliability, and support consistent processing and cleaning performance.
Ultimately, the right gasket is not simply the material with the highest temperature rating, broadest chemical resistance, or longest list of certifications. It is the gasket whose material properties, documentation, and mechanical performance are suited to the specific application.
Need Help Selecting Gaskets for Pharmaceutical Processing?
Specialty Gaskets Inc. manufactures and supplies gasket materials and custom sealing solutions for a wide range of industrial applications. Whether you're evaluating materials for pharmaceutical processing equipment, replacing an existing gasket, or developing a new component, our team can help identify sealing materials suited to your application's operating requirements.
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