--- title: "Manway Gasket Materials: Silicone vs. EPDM vs. Viton — How to Choose" date: 2026-07-04T01:54:54Z modified: 2026-07-16T03:33:09Z permalink: "https://www.hyflowtech.com/blog/basic/manway-gasket-materials-silicone-vs-epdm-vs-viton/" type: post status: publish excerpt: "" wpid: 1971 categories: - basic featured_image: "https://www.hyflowtech.com/wp-content/uploads/2026/07/image-88.webp" featured_image_alt: Siliconevs.EPDMvs.Viton-How to Choose timestamp: 2026-07-16T03:33:09Z tags: - basic --- Choosing the correct tank seal prevents unscheduled process downtime and product leaks. This technical guide compares silicone, EPDM, and Viton elastomers for sanitary storage vessels. We analyze chemical compatibility, temperature limits, steam resistance, and industry standards to simplify your selection process. ## Why Does Material Selection for a Tank Manway Gasket Matter? A tank manway gasket seals the large access hatch on industrial storage vessels. These gaskets prevent fluid escape and block outside contaminants. They must withstand not only pressure and temperature cycles. They must also manage cleaning chemicals without degrading. Choosing the wrong elastomer leads to premature seal failure. It can also cause chemical compatibility disasters and unplanned shutdowns. Such downtime events can cost thousands of dollars per hour across major industries. The total incident cost is often five to ten times the physical seal price. In one documented case, EPDM seals in a chemical transfer pump failed every two months. Each failure caused hours of downtime. It also cost $15,000 in lost production. After replacing EPDM with Viton, seal life extended to 18 months. It also reduced failure costs. ## Silicone, EPDM, and Viton: What Is the Difference? These elastomers differ in chemical backbones. They also differ in continuous temperature limits and resistance profiles. Engineers must evaluate these properties before specifying a manway gasket. Standard properties like tensile strength vary by grade. ### Silicone: The High-Flexibility Option Silicone has an inorganic backbone. This not only provides excellent low-temperature flexibility. It also creates thermal stability. Food-grade silicone offers a simple extractable profile and deforms easily under light loads. It works best in static applications without abrasive media. However, silicone has significant engineering limitations. It has lower tensile strength than EPDM and Viton. It also has poor resistance to acids and strong alkalis. It also performs poorly with hot steam. Thus, silicone has limited use in clean-in-place cycles. ### EPDM: The Aqueous and Steam Specialist EPDM is a peroxide-cured synthetic rubber. Peroxide curing increases its temperature limit to 300°F. Sulfur curing is also an option. Curing improves tensile strength. EPDM performs well in water and hot steam. It also excels in ozone and dilute acids. This makes it the ideal option for clean-in-place sanitization. However, EPDM degrades rapidly in petroleum products, which cause severe swelling and seal failure. ### Viton: The Inert Elastomer for Aggressive Media Viton is a premium synthetic rubber. Its fluorine-carbon bonds create chemical inertness. This material not only resists fuels and oils. It also resists hydrocarbons. Viton maintains properties where other elastomers lose elasticity. However, standard Viton degrades rapidly in polar solvents. Ketones, low molecular weight esters, and organic acids cause swift failure. Specialized formulations handle these incompatible fluids. ## How Do You Select Gaskets Based on Operating Conditions? Engineers prioritize chemical compatibility first. Afterward, they check operating temperatures. Finally, cost comes third. This approach ensures optimal seal life without unnecessary premiums. Mismatched gaskets always fail rapidly under actual operating conditions. ![Gaskets Based on Operating Conditions](https://www.hyflowtech.com/wp-content/uploads/2026/07/image-89-1200x670.webp) ### Comparing Elastomer Material Properties Engineers must compare specific technical parameters before choosing a tank manway gasket. The table below outlines standard performance metrics for the three main elastomers. | **Property** | **Silicone** | **EPDM (Peroxide-Cured)** | **Viton (Standard FKM)** | | --- | --- | --- | --- | | Temperature Range | -80°F to 350°F | -60°F to 300°F | -20°F to 400°F | | Tensile Strength | Moderate | 1,000 to 3,000 psi | 1,195 to 2,238 psi | | Compression Set | Good | 9% at 212°F | 9% to 10% (Room Temp) | | Steam Resistance | Poor | Excellent | Poor (Standard Grades) | | Chemical Limits | Poor Steam/Acids | Swells in Petroleum | Degrades in Ketones | | Relative Cost | Medium | Low | High (8-10x EPDM) | ### Sizing and Physical Dimensions of Tank Seals Proper sealing requires a precise fit. Standard tank manway gasket dimensions must match the hatch diameter and groove depth to prevent extrusion. Incorrect dimensions cause the elastomer to extrude under high clamping forces. Suppliers offer standard [tank manway gasket](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/post/tank-manway-cover-vs-manhole-cover.md) sizes for circular and oval doors. Nominal diameters are around 300- 600 mm. Engineers must verify dimensional tolerances and profiles before ordering. ## What Are the Real-World Applications for These Gaskets? Process industries have distinct sanitary and regulatory requirements for sealing materials. High-purity sectors must use certified compounds to ensure absolute biological safety. The chosen seal must match process chemistry and cleaning protocols. ### Brewing and Beverage Processing Challenges Brewing relies on biological purity; leaks ruin entire batches. Brewery manway gaskets must withstand harsh steam and caustic cleaners. Gaskets must also not contaminate the beverage. Peroxide-cured EPDM is the standard for brewery gaskets. It resists hot steam and cleaning alkalis. It also prevents flavor taint. EPDM is soft enough to seal doors under low pressure. ### Biopharmaceutical and High-Purity Requirements Biopharms operate with strict biological purity. Thus, components like tank manway gaskets must not leach chemicals into product streams. Peroxide-cured EPDM fits water and steam systems. Silicone suits single-use processes due to low leachability. Materials must also comply with USP Class VI and FDA 21 CFR 177.2600 rules. ### New Energy and Fine Chemical Processing Fine chemical plants process highly corrosive acids. They produce organic solvents and lithium battery slurries. Aggressive media cause conventional elastomers to swell and crack. This can result in rapid failure. Specifying the correct manway seal material prevents hazardous leaks. It also ensures operator safety. Engineers often select fluorocarbon elastomers for these aggressive environments. Viton is one good example. The material provides key performance advantages in high-solid processes. For example, standard Viton seals can resist strong acids. Its low permeability minimizes chemical migration through the material. However, some elastomers have limits. For instance, Viton becomes brittle in low temperatures. Ketones and organic acids degrade the polymer structure quickly. Operators must test seals under actual service conditions before deploying standard grades. ![Brewing & Beverage Biopharma Fine Chemicals](https://www.hyflowtech.com/wp-content/uploads/2026/07/image-90-1200x670.webp)## Why Choose HEYI for Your Sanitary Valve and Gasket Needs? [ ![Wholesale Stainless Steel Sanitary Manway Covers and Valves](https://hyflowtech.b-cdn.net/wp-content/uploads/2026/05/%E5%85%A8%E8%A7%86%E9%95%9C%E4%BA%BA%E5%AD%94sigh-glass-manhole-cover.png) **Sanitary Manway Covers** B2B catalog for global buyers, featuring various stainless steel sanitary manway covers and fluid valves for quick specification and inquiry. Explore Catalog ](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/taxonomy/product_cat/sanitary-manway-covers.md) HEYI is a manufacturer of sanitary valves and fittings in Zhejiang, China. It has supplied these products across 30 countries since 2014. Products meet strict GMP, FDA, and 3-A hygienic standards. The company stocks standard parts and customizes[ sanitary manway covers](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/taxonomy/product_cat/sanitary-manway-covers.md). HEYI’s sealing materials for valves are PTFE, silicone rubber, and fluororubber. Sealing configurations vary to maximize equipment service life. These include: - Silicone sealing rings for stainless hoppers and manholes. - [Sanitary butterfly valves](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/taxonomy/product_cat/sanitary-butterfly-valves.md) with silicone rubber seats. - [Sanitary ball valves](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/taxonomy/product_cat/sanitary-ball-valves.md) with PTFE seals to handle high pressure. Choose HEYI for your sanitary valve and fitting needs today. Request a quote to secure your processing lines. Contact the technical team via email to discuss requirements. [ Contact US ](https://www.hyflowtech.com/wp-content/uploads/wp-mfa-exports/page/contact-us.md)