Check valves, often called non-return valves, are indispensable in fluid systems because they prevent backflow, protecting upstream equipment like pumps and compressors from damage or contamination How Check Valves Protect Your Piping System. Their simple, automatic function belies the critical role materials play. The body and seal materials determine the valve's ability to withstand pressure, temperature, and corrosive fluids.
1. Ductile Iron: The Heavy-Duty Workhorse
Ductile Iron is a cornerstone for many check valve applications, especially in large-diameter piping for water, wastewater, and general utility services.
Key Strengths:
- Strength and Formability: Contains >3% carbon, allowing flexibility while being stronger than traditional cast iron.
- Impact Resistance: Resists sudden shocks without breaking or bending.
- Applications: Ideal for municipal lines, fire protection, and industrial systems needing robust, flanged valves, like our Ductile Iron Flanged Swing Check Valve.
2. Stainless Steel: The Corrosion Champion
Stainless Steel (304 and 316) is the most popular choice due to its superior corrosion resistance and durability.
Key Strengths:
- Corrosion Resistance: Resists rust in water, steam, and moist air. 316 offers enhanced protection, perfect for chemical, marine, and pharmaceutical industries.
- High Performance: Suitable for high-pressure and high-temperature environments.
- Types: Found in many designs, from Threaded Swing Check Valves to Flanged Lift Check Valves.
3. Brass and Bronze: Versatile and Machinable
Brass and Bronze are copper alloys used in smaller check valves for residential, commercial, and general-purpose water systems.
Key Strengths:
- Machinability: Easier to machine, reducing manufacturing costs compared to stainless steel.
- Corrosion Resistance: Good resistance for plumbing and drinking water systems.
- Price Point: Balance between cost and corrosion protection. See our Brass Threaded Swing Check Valve.
4. Non-Metallic Options: PVC, CPVC, and PP
For highly corrosive fluids or cost-sensitive projects, plastics offer excellent performance.
Key Strengths:
- Corrosion Resistance: Materials like PVC, CPVC, and Polypropylene (PP) are nearly inert to many acids, bases, and solvents.
- Chemical Processing: PP is favored in laboratories and chemical plants due to its superior resistance compared to PVC/CPVC.
- Lightweight & Cost-Effective: Plastic check valves are easy to install and budget-friendly, ideal for Irrigation and Wastewater Treatment. Explore our UPVC Swing Check Valve.
Beyond the Body: Sealing Materials
Choosing the right seat and seal elastomer is critical for bubble-tight performance:
- EPDM (Ethylene Propylene Diene Monomer): Excellent for water and steam.
- NBR (Nitrile Butadiene Rubber): Best for oils and fuels.
- FKM (Fluoroelastomer / Viton™): Outstanding chemical and high-temperature resistance.
The correct pairing of body and trim materials ensures compliance with standards like API & ASME Valve Standards, which cover materials, testing, and pressure ratings.
Final Thoughts
Selecting the right check valve material is not just about the body but also the seals. Matching materials to fluid properties—temperature, concentration, and corrosiveness—is essential for system longevity, efficiency, and safety.
