A trap shall not extend nearer to the floor than how many inches, except for certain fixtures?

The correct answer is 12 inches because plumbing codes require that the trap, which is designed to prevent sewer gases from entering the building, must be positioned at a certain height above the floor to ensure proper function and accessibility for maintenance. By stipulating that traps should not extend nearer to the floor than 12 inches, the code aims to prevent potential damage or blockages that could arise if the trap is too low, such as being susceptible to backflow or debris accumulation.

The regulation also allows for specific fixtures, such as those requiring lower trap heights due to their design or purpose, to deviate from this general requirement. The 12-inch guideline represents a commonly accepted standard in plumbing practice, promoting both safety and effective wastewater management in various applications.