Final answer:
The IPC does allow drainage pipes to be installed with a grade, and the minimum slope required depends on the diameter of the pipe -- 1/4 inch per foot for general horizontal pipes, 1 1/2 inch per foot for smaller pipes, and 1/8 inch per foot for pipes between 3 to 6 inches in diameter.
Step-by-step explanation:
The statement that the IPC does not allow any drainage pipe to be installed at a 1/2-inch grade is False. The International Plumbing Code (IPC) does have specific requirements for the slope, or grade, of drainage pipes. Generally, horizontal drainage pipes should have a minimum slope of 1/4 inch per foot (2% grade). For pipes that are 2½ inches in diameter or smaller, a 1½ inch per foot (12.5% grade) slope is often required, and for those between 3 inches and 6 inches, the minimum slope usually is 1/8 inch per foot (1% grade).
For example, a 4-inch drain pipe would require a minimum slope of 1/8 inch per foot. This ensures that the water flow remains adequate for effective drainage, avoiding issues such as clogging and stagnant water.