When to Use a Butterfly Valve: 6 Top Scenarios (HVAC, Water Treatment & More)

First: What is a butterfly valve?

Before discussing when to use a butterfly valve, let’s first understand what a butterfly valve is. At its core, it’s a simple device used to control the flow of fluids (such as water, chemicals, or even slurries) through a pipe. Its key component is a flat, round “disc” attached to a central stem. When the stem rotates 90 degrees, the disc moves with it.

• Closed:The disc is vertical (perpendicular to the pipe), almost completely blocking flow.
• Open:The disc lies flat (parallel to the pipe), allowing fluid to pass easily.
• Partially open:You can stop the disc halfway (or anywhere in between) to slow or regulate flow, but the precision isn’t as high as with other valves.

Most butterfly valves also have an O-ring or seal around the stem to prevent leaks. Butterfly valves are small, lightweight, and less expensive than larger valves like gate or globe valves. This is why they’re so popular in many industries, but again, they’re not a universal solution.

When to Use a Butterfly Valve: Best Practices

Butterfly valves shine in specific situations. The following are the best times to choose a butterfly valve, based on actual usage and industry standards.

1. When fast opening/closing or emergency shutoff is required

One of the greatest advantages of a butterfly valve is its speed. Since it only requires a 90-degree rotation to open or close, it is ideal for applications requiring a quick response. For example:

• Fire suppression systems: If a fire breaks out, valves need to open quickly to deliver water to sprinklers. Butterfly valves can accomplish this in seconds.
• Emergency shutdowns in factories: If a chemical pipeline leaks, quickly shutting off the water flow can prevent an accident.
• Pumping stations:When a pump needs to be suddenly started or stopped, a butterfly valve can respond instantly.

This speed far surpasses valves like gate valves, which require multiple rotations to open or close, and in some cases, can take minutes!

2. When space is limited

Butterfly valves are compact and much smaller than gate or globe valves of similar size.For example:

• Heating, ventilation, and air conditioning (HVAC) systems:Space is limited for equipment used to heat or cool a building. Butterfly valves can be easily installed in narrow piping systems or chilled water lines, whereas larger valves may require additional space.
• Underground Pipes:Some butterfly valves are designed to be buried underground, saving floor space. In cities, these butterfly valves are used in water mains or sewage lines where there’s no room for a large valve box.

3. When Handling Large Pipes

When it comes to large pipes, butterfly valves are your best choice. When fully open, the butterfly valve’s flat disc barely obstructs the flow, resulting in minimal “pressure drop” as the fluid passes through the pipe, meaning less energy is wasted pushing the fluid through the pipe. Butterfly valves are ideal for the following applications:

• Water Supply: Cities use large butterfly valves to transport water from water treatment plants to homes. These pipes can be 20 inches in diameter or larger, and butterfly valves can control the flow without slowing it down.
• Cooling Towers:Factories and power plants use cooling towers to keep their machinery cool. The large pipes leading to these cooling towers require valves capable of handling high flow rates, and butterfly valves excel in this area.
• Wastewater treatment systems: Transporting wastewater through large pipes requires a valve that’s resistant to clogging. The butterfly valve’s simple design is well-suited for this application, reducing the likelihood of debris becoming stuck.

4. When handling “special” media

“Media” refers to any substance flowing through a pipe, and some media are more challenging to handle than others. Butterfly valves are well-suited for handling viscous, easily clogged media, such as:

• Slurries: A mixture of water and mud, or concrete at a construction site. The wide opening of a butterfly valve allows these thick fluids to pass smoothly.
• Viscous fluids:Oils, syrups, and even some foods (like ketchup in factories) are viscous. Unlike ball valves (which tend to become sticky) or globe valves (which have narrow openings), butterfly valves lack small parts, making these fluids less susceptible to clogging.
• Chemicals (Use the right material):If the valve is made of corrosion-resistant metal (such as 316 stainless steel), it can handle mild chemicals. Simply choose a butterfly valve material that’s suitable for the chemicals you’re dealing with!

5. When you want to save money and reduce maintenance

• Butterfly valves have low upfront costs:They are easier to manufacture than gate or globe valves, making them cheaper to purchase. For example, a 6-inch butterfly valve may cost half the price of a 6-inch globe valve.
• They require virtually no maintenance: They have few moving parts—just the disc, stem, and seals. This means they are less susceptible to damage or wear. You may only need to lubricate the stem once a year.

This makes them ideal for small businesses, schools, or cities that need a reliable valve on a tight budget.

6. When you need basic flow control rather than ultra-high precision

Butterfly valves aren’t the best fit for applications that require precise flow control (such as medical equipment). However, they are very effective for basic regulation, such as:

• HVAC systems: Regulating the flow of chilled water to each floor of a building. Perfect regulation isn’t necessary, as long as it maintains the right temperature.
• Irrigation: Watering a farm or park. You can open the valve halfway to provide the right amount of water to the plants, eliminating the need for very precise settings.
• Chemical mixing:In some factories, mixing two chemicals requires only a rough flow rate. A butterfly valve can do the job without overcomplicating things.

If you need a more precise flow rate, you might want a globe valve—but for most everyday tasks, a butterfly valve is more than adequate.

When Not to Use a Butterfly Valve

Even the best tools have limitations. You should choose a different valve in the following situations:

1. High-Pressure or High-Temperature Operations

Butterfly valves are not suitable for extremely hot or high-pressure environments. For example:

• High-Pressure Piping: If you are transporting steam in a power plant (where pressures can reach 1,000 psi or higher) or transporting oil through underground pipelines, a butterfly valve may leak. The disc and seals cannot withstand high pressures. Therefore, use a gate valve or a specialized “high-performance” butterfly valve.
• High-Temperature Fluids:If the fluid temperature exceeds 300°F (150°C), such as molten metal or superheated steam, a standard butterfly valve will deform or crack. In these cases, a globe valve or ball valve is a better choice.

2. When You Need Perfect Precision

As we mentioned earlier, butterfly valves are suitable for basic regulation, but not for applications where every drop counts. For example:

Medical Devices and Laboratory Experiments: Mixing chemicals in a lab often requires precise flow rates. The slightest “wobble” of a partially open butterfly valve can disrupt the experiment. Therefore, you need to choose a high-precision valve.

3. Pipeline Cleaning

“Pigging” involves inserting a small device (a pig) into a pipe for cleaning. Butterfly valves are not suited for this task because the disc remains inside the pipe, even when open. The pig could hit the disc and become stuck. If you need to clean the pipe this way, use a gate valve or ball valve, which are designed to allow the pig to pass through.

4. When the fluid contains hard solid particles

We previously mentioned that butterfly valves are suitable for slurries, but this is different from fluids containing hard solid particles. For example:

• Sand or gravel in the water: These small stones can scratch the valve disc or seal, causing the butterfly valve to leak over time.
• Clumpy food:If you are pumping soup containing large pieces of vegetables, these pieces of food may become lodged between the disc and the pipe, preventing the valve from fully closing. In this case, a gate valve with a larger opening may be more suitable.

Butterfly Valves vs. Other Common Valves: A Quick Comparison

Sometimes, it’s hard to choose between a butterfly valve and another type. Here’s a simple breakdown to help you decide:

For example: If you’re installing a valve in a small HVAC closet with 6-inch pipes, a butterfly valve is perfect. If you need a valve for a small, leak-free chemical pipe in a lab, a ball valve is better.

Final Tips for Choosing a Butterfly Valve

If you’ve decided a butterfly valve is right for you, here are some quick selection tips:

1. Choose the right size: Select a valve that matches the pipe size (e.g., a 4-inch pipe requires a 4-inch valve).
2. Choose the right material: For water, use ductile iron. For chemicals, use 316 stainless steel. For food, use food-grade plastic or stainless steel.
3. Check the pressure and temperature ratings: Make sure the valve can withstand the pressure and heat of the fluid. Most standard valves have an operating pressure and temperature of up to 150 psi and an operating temperature of up to 250°F.
4. Determine the actuation method: Do you want manual adjustment (using a lever or handwheel) or automatic adjustment (using an electric or pneumatic motor)? For larger valves, automatic actuation is more convenient.

Wrapping Up

Butterfly valves aren’t the “perfect” valve for every application, but they are among the most versatile and cost-effective valves on the market. They work best when you need speed, space savings, low cost, and reliability. Just avoid using them for high-pressure, high-temperature, or ultra-precision applications.