Which type of connection requires the least amount of labor and sealing in ductwork installation?

The slip joint connection is designed for ease of installation and requires minimal labor and sealing. This type of connection is created by simply overlapping one piece of ductwork into another, which allows for quick assembly without the need for complex fittings or excessive fastening. The inherent design of the slip joint minimizes the time spent on both assembly and sealing, making it ideal for situations where efficiency is crucial.

In contrast, flanged connections often require additional components like flanges and fasteners, which can lead to longer installation times and more labor-intensive work. Welded connections, while providing a strong and airtight seal, require specialized equipment and skilled labor to perform the welding, adding significantly to the time and effort involved. Taped connections can also demand considerable effort to ensure they create an adequate seal, and the quality can vary depending on the method and tape used.

Therefore, the slip joint's straightforward approach allows for quicker installation while reducing the need for extensive sealing, making it the most labor-efficient option among the types of connections listed.