Selecting a valve material for your next HVAC project can make or break your application. Each material is selected based on its unique characteristics, advantages, and limitations, tailored to specific applications and environmental conditions.
In this valve material selection guide, we’ll review the common material choices used in the HVAC industry, the types of valves available, and considerations to keep in mind.
Common Valve Materials and Their Properties
Valves are commonly made from one of four material categories – stainless steel, carbon steel, brass, and bronze, or alloy materials. Each category has its unique characteristics and advantages or limitations.
Stainless Steel
Stainless steel is typically the best option for corrosion resistance. This material is resistant to a wide range of chemicals, temperatures, and other environmental conditions. Stainless steel is widely used in the food and beverage and pharmaceutical industries since it’s easy to clean and has non-contaminating properties.
Carbon Steel
Carbon steel is commonly found in high-pressure environments due to its high tensile strength. Additionally, carbon steel offers wear resistance, which is beneficial for high-flow rate or abrasive liquid applications.
Bronze and Brass
Bronze and brass are ideal for water applications. Brass has corrosion resistance to water, while bronze is noted for its strength and resistance to seawater and cavitation.
Other Alloy Materials
Other alloy materials such as Inconel, titanium, or tungsten may be considered for their exceptional corrosion resistance and strength at high temperatures. These are often found in highly corrosive environments such as chemical processing.
Types of Valves & Material Selection
There are many different types of valves, each with unique characteristics. However, 5 types of valves are most well-known:
- Bypass valves
- Check valves
- Pressure relief valves
- Shrader valves
- Pneumatic solenoid valves
1. Bypass Valves
Bypass valves help regulate fluid or gas flow in a system. These valves are designed to divert the flow to a secondary route, often to balance pressure or manage the load on the system.
While material choice is heavily influenced by the fluid type and operating conditions, brass or stainless steel are most commonly used due to their corrosion resistance and durability.
2. Check Valves
Check valves allow fluid to pass through in one direction only. Once the pressure builds up to a set value, the fluid starts to flow through the valve – but as soon as the pressure drops below the set value, the valve closes and does not allow any fluid to flow backward.
Typically, the material choice varies widely from brass and bronze for general water systems to stainless steel for chemical or corrosive applications.
Some examples of check valves include hydraulic tensioner check valves, engine oil check valves, and engine oil flow check valves.
3. Pressure Relief Valves
Pressure relief valves or high-pressure pneumatic safety valves are designed to do what their name says – release pressure from a system. These are passive valves that open when the gas pressure exceeds a set value (typically very high), designed to protect the rest of the pneumatic circuit from damage if there is a spike in pressure.
These valves must use materials that can withstand high pressures and temperatures, such as stainless steel.
Some examples of pressure relief valves include CO2 pressure relief valves, refrigerant pressure relief valves, and air pressure relief valves.
4. Shrader Valves
Shrader valves are a type of check valve that has a spring-loaded pin, which allows air or gas in and keeps it from escaping until connected to a pump.
Materials can vary for Shrader valves depending on the fluid type and required level of corrosion resistance. Typically, materials include brass or stainless steel.
5. Pneumatic Solenoid Valves
Solenoid valves rely on an electric current to open or close the valve – controlling the flow of liquid or gases. These valves are binary, so they’re either fully opened or closed, similar to a light switch functionality.
Depending on the fluid type and application, materials vary from brass to stainless steel or plastic.
Some examples of pneumatic solenoid valves include refrigerant solenoid valves and high-pressure pneumatic solenoid valves.
Considerations for Valve Material Selection
When it comes to valve material selection, there are many options available. To keep it simple, we’ve broken it down into 3 things to consider before choosing a valve material.
- Cost vs. performance
- Corrosion and rust resistance
- Mechanical properties
1. Cost vs. Performance
When choosing valve material, it’s noticeable when you choose the cheaper option. Alloys with high quality tend to be more costly than others. However, the investment will be worth it in the long run.
Most of the time, it’s best to avoid plastic valve materials. Although cheaper, they can’t perform nearly as well or as long as metal valves and may result in additional expenses from accidents or breaks.
2. Corrosion and Rust Resistance
It’s no secret that certain materials perform better than others when it comes to chemical reactions. Typically, stainless steel or titanium are better choices to withstand corrosion from chemicals or acids.
3. Mechanical Properties
If you’re planning on a high-pressure or high-temperature application, your valve material needs to be able to withstand these conditions.
Carbon steel and stainless steel offer improved strength and a significantly higher resistance to thermal stress than bronze or brass. In extreme temperatures, Inconel material may be required.
Valve Material Selection in the HVAC Industry
Various valves are used in HVAC systems. In most cases, the valves used in HVAC systems are made from brass, stainless steel, or plated carbon steel for corrosion resistance. However, there are several different types of valves.
Bypass valves, pressure relief valves, and pneumatic solenoid valves are all used to regulate the pressure of the refrigerant in refrigeration and air conditioning systems. If the pressure gets too high in the system, it can cause the compressor motor to overheat and malfunction.
Pressure relief valves are also used on boiler and hot water heaters to prevent pressure-related failures. While on the other hand, Shrader valves allow refrigerant to be safely added or removed from refrigeration and AC systems.
Making the Right Choice: The Importance of HVAC Material Selection
When you select a valve material, you want to ensure that it's the best for your project. Whether you prioritize corrosion resistance, cost, or performance – the choice you make can make or break your application.
Understanding the unique properties of each material is critical to make an informed choice. Before you make your decision, reach out to our team at Alpha Precision Group to find the best material for you.
