Selecting the appropriate gasket materials is extremely important. Gaskets serve as mechanical seals in equipment and fluid processing systems to keep contaminants out of sensitive areas and prevent fluids from leaking.
The importance of choosing the right gasket materials can’t be overemphasized. Gaskets are mechanical seals used in handling equipment and fluid processing in order to prevent contaminants from entering sensitive areas and fluids from escaping.
The material used in making the gasket is one of the most crucial factors you should consider. Using the wrong material can cause gasket failure, resulting in production delays, severe damage to equipment, shorter product life, or injury. Therefore, material selection begins with assessing the application in which the gasket will be employed in order to ensure it meets specific requirements.
This article covers the essential factors to consider when selecting gasket materials. But first, let’s start by highlighting the roles of gaskets and the types of gasket materials you should know:
The Role of Gaskets in the Piping/Gas Industry
Gaskets are compressible components used in making seals and covering the intersection that connects two surfaces. They are used extensively in the piping/gas industry as seals between pipe flanges.
Gaskets are utilized for stopping leakage between 2 surfaces while compressed. This is because, over time, the joints will corrode and break if gaskets are absent.
Gaskets can function exceptionally well when appropriately compressed in order to create a pressure-tight seal. However, they must be manufactured with the right materials in order to deliver their assignment.
The materials used in making gaskets must be easily molded and possess the right physical, chemical, and temperature capabilities.
Types of Gasket Materials
There are several types of gasket materials available. Each of these materials offers unique characteristics that make it highly suitable for specific applications.
Some of the well-known gasket materials you should know include:
Compressed Non-Asbestos
These materials generally contain non-asbestos fibers – e.g., aramid fibers or fiberglass – combined with rubber. This formulation leads to better pressure performance and temperature.
Some examples of compressed non-asbestos materials include:
- Durlon ®
- Thermoseal ®
- Teadit ®, etc.
Rubber
Rubber is available, but in several grades and formulations that make the ideal for a wide variety of applications with varying operating and environmental conditions. In addition, it can be processed using more than a few manufacturing processes, depending significantly on the production and component specifications.
The following are some rubber materials you should know:
- Butyl
- Conductive silicone
- Latex
- Flourosilicone
- Natural (Gum) Rubber
- Cloth-Inserted (CI)
- Silicone
- Nitrile (Buna-N)
- Urethane
- Thermoplastic Rubber (TPR)
- Polyurethane
- Urethane
- SBR (Red Rubber), etc.
Rubber Molding Compounds
These compounds are employed in the following molding operations to create application-specific gaskets in a wide variety of sizes and shapes:
- Injection molding
- Compression molding
- Transfer molding
Some rubber molding compounds materials include:
- Silicone (MCQ)
- Nitrile, Buna-N (NBR)
- Butyl (IIR)
- Hydrogenated Acrylonitrile (HNBR)
- Fluorosilicone (FVMQ, FMQ)
- Epichlorohydrin (EPI)
- Natural Rubber
- Custom compounds and colors, etc.
Open-Cell Sponge Rubber
These feature interconnected cells that allow liquids, gases, as well as other media to permeate the material. It comes in these densities:
- Soft
- Medium
- Medium-firm
- Firm
- Extra firm
Some open-cell sponge materials include:
- Natural Open Cell Storage
- SBR Open Cell Sponge
- Neoprene Open Cell Sponge
Closed-Cell Sponge Rubber
These feature fully-separated cells from surrounding cells in order to prevent fluid infusions. Closed-cell sponge rubber is available in medium, soft, and hard densities.
Some closed-cell sponge rubber materials include:
- Neoprene Sponge
- EPDM Sponge
- Silicone Sponge
- PVC-Nitrile Sponge, etc.
Factors to Consider When Selecting Gasket Materials
Here are the key considerations to bear in mind for selecting suitable gasket materials:
Temperature
The #1 consideration when selecting gasket materials is temperature. Temperature can change the characteristics of almost any material. Extreme heat, frigid conditions, and widely fluctuating temperatures can significantly affect material sealing properties, overall performance, and maximum allowable stress.
Material options for gaskets become limited as the application temperature rises. Moreover, the time a specific gasket material is exposed to maximum temperatures should help guide your selection.
Industry/Product Standards
Every industry – and product – comes with standards that must be adhered to, depending significantly on your location, industry, and product. Some broad certifications that may be applicable include:
- UL – International Safety
- ASTM – American Society for Testing and Materials
- ANSI – American National Standards Institute, etc.
The Environment
Some environmental factors can significantly impact the lifespan of a gasket. Asides from temperature, the following factors can have a profound impact on the success or failure of your gasket:
- Exposure to ultra-violet rays: – Exposure to ultra-violet rays can cause gasket degradation
- Resistance to chemicals: – Corrosive, acidic, abrasive, or toxic chemicals can impact the overall integrity of the gasket.
- Resistance to moisture: – Absorbent materials may deteriorate when exposed to moisture for a long time, resulting in gasket failure
Durometer
A durometer is a standardized or evaluated way of measuring the hardness of a material or the firmness of a foam. Durometer testers come with measurement scales ranging from 0 to 100, indicating the force required to achieve a particular level of indentation.
Lower numbers indicate flexible and soft materials, while higher numbers indicate firm or harder materials. The following material classification selects testers:
- Shore 00: – Extremely soft materials such as cellular sponge and foam
- Shore A: – Firmer rubber materials used for rubber sheeting and O-ring
- Shore D: – Hard plastics as well as very hard rubber compound
The durometer is an essential factor in sealing performance. Gasket materials must be soft enough to fill the gap between 2 surfaces without extruding annoyingly from the joint. Yet, it must be hard enough to capably withstand the impact or pressure it will eventually encounter.
Compression Set
The compression set of a material refers to the amount of permanent deformation that a gasket sustains when under extreme force or intense pressure. As a result, gasket performance eventually diminishes over time. This is why it is crucial to note that material recovery abilities matter much more with constant vs. periodic compression.
Standards for measuring the compression set of a material vary. So, working with a trusted partner is essential when selecting the best material for gaskets.
Conclusion
The importance of choosing the most suitable material for your gasket cannot be overstated. Using the wrong material type to make gaskets will result in flooding or the escape of fluid from sensitive areas or contaminants entering those areas without hindrance.
Therefore, it is crucial to know the right type of materials to use for making gaskets suitable for your application. You may need to talk to your supplier if unsure of the perfect material type for your gasket.