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For trap arm lengths of 4 inches and higher, what is the required downward slope per foot?

  1. 1/4 inch

  2. 1/2 inch

  3. 1/8 inch

  4. 3/8 inch

The correct answer is: 1/8 inch

A A downward slope of 1/4 inch per foot would be too steep and could cause solids to move through the pipe too quickly, potentially causing clogs. B: A downward slope of 1/2 inch per foot would also be too steep and could result in excessive velocity, leading to the potential for water hammer and pipe erosion. D: A downward slope of 3/8 inch per foot would be too steep and could result in excessive flow and potential for clogs, as well as increased wear and tear on the pipes. Therefore, the recommended downward slope for trap arm lengths of 4 inches or higher is 1/8 inch per foot. This slope allows for efficient drainage without the risk of excessive velocity or erosion.