Which of these describes a vertical plumbing pipe?

A vertical plumbing pipe is defined as a pipe that runs vertically, meaning it is oriented in an up-and-down position rather than horizontally. For a pipe to be categorized as vertical, it should maintain an angle that is predominantly upward or downward with respect to the ground. The choice that describes this accurately states that a vertical pipe exceeds an angle of 45 degrees with horizontal, indicating that it is primarily vertical rather than being oriented at a shallow angle.

The rationale behind this classification is that pipes functioning primarily in a vertical orientation are crucial for specific plumbing tasks such as waste removal, water supply, and venting systems. By exceeding an angle of 45 degrees, it confirms the pipe's position is indeed vertical and not just leaning or slightly tilted, which characterizes true verticality in plumbing.

In contrast, options suggesting any angle less than 45 degrees or identifying horizontal pipes do not reflect the definition of a vertical pipe and thus wouldn't fit the criteria for vertical plumbing. Additionally, a completely straight pipe does not inherently indicate vertical orientation without specifying its angle relative to horizontal, which could lead to misinterpretation.