NCCER Sheet Metal Level 3 Practice Test

To determine the free area of the linear slot diffuser, you'll start with the dimensions provided and the K factor. The free area is typically calculated by multiplying the dimensions of the slot. In this case, the diffuser measures 8 inches in height and 24 inches in length.

The formula for calculating the free area (A) in square inches is:

\[ A = Height \times Length \]

Using this formula, the calculation would be:

\[ A = 8 \, \text{inches} \times 24 \, \text{inches} = 192 \, \text{square inches} \]

However, the K factor must also be considered when referring to the effective area in duct design. The K factor, which is the discharge coefficient, accounts for the fact that not all of the available area is effective for flow. In this scenario, the K factor of 0.78 implies that you need to apply it to the calculated free area to find the effective area.

To find the free area in relation to the K factor, you would multiply the total area by the K factor:

\[ Effective Area = A \times K \]

Calculating that:

\[ Effective Area = 192 \, \text{square