Which class uses a percolation time to determine the loading rate of the side walls?

• A. Class 1
• B. Class 2
• C. Class 3
• D. Not specified

Answer: (B)

The loading rate for the side walls is tied to how quickly water can move through the soil, which is exactly what the percolation time measures. In this soil class, designers use that percolation time to set the rate at which wastewater can be applied to the side walls of the absorption area. If the percolation time is short, the soil can absorb water quickly, allowing a higher loading rate. If it’s long, the soil absorbs more slowly, so the loading rate must be lowered to avoid oversaturation or surface pooling. This approach makes the design responsive to the actual infiltration behavior of the site. Other soil classes may use different assessment methods or fixed values, but for this class the percolation time directly determines the loading rate.