Which of the following is not a requirement for air dispersion system?

In an air dispersion system, the requirement for a unit to be located in a separate room is not necessary. While certain applications may benefit from separation to minimize disruption or control environmental conditions, it is not a universal requirement for all air dispersion systems. The other choices represent essential features that contribute to the system's performance and efficiency.

Accessibility for maintenance is critical because it ensures that the system can be easily serviced and any necessary repairs or routine maintenance can be conducted promptly, which is vital for maintaining system efficiency and safety.

Equipping the system with variable speed fans allows for better control over air movement and energy consumption. This flexibility is important for adapting to varying conditions and ensuring optimal performance across different operating scenarios.

Designing the system to minimize noise is also important as it impacts the comfort of the environment where the system operates. Keeping noise levels low is a common requirement in many applications, especially in residential and commercial settings where excessive noise can be disruptive.

Thus, while the location of an air dispersion system may be important in some cases, it is not a standard requirement compared to the aspects of maintenance access, variable speed capabilities, and noise reduction.