What type of flow meter is often used in both fluid and air applications?

The correct answer encompasses various types of flow meters, highlighting their versatility in different applications. Mass flow meters measure the mass of the fluid passing through the device, making them suitable for both gas and liquid applications. They are capable of providing accurate readings regardless of the fluid’s density fluctuations, which is essential in many HVAC systems.

Velocity flow meters determine the speed at which a fluid flows through a pipe, relying on the relationship between flow rate and velocity. They are effective in measuring air in HVAC systems as well as liquids in various industrial processes. Their applicability across both domains underscores their importance.

Magnetic flow meters, utilizing Faraday's law of electromagnetic induction, are also applicable for both conductive liquid flow and certain air applications when appropriately configured. They provide real-time data and are particularly useful in water treatment and other processes.

By stating "all of the above," it acknowledges that each type of meter has unique characteristics and can be employed in both fluid and air applications depending on the specific requirements of the system being monitored. This collective approach emphasizes the breadth of options available when selecting a flow meter for HVAC or other engineering needs, ensuring that professionals can choose the most suitable technology for their applications.