Master Plumber Practice Exam 2026 – Complete Prep Guide

The material that is not approved for the installation of an external trap for a urinal is drawn-brass tubing traps. This is because drawn-brass tubing can corrode over time, particularly when exposed to the acidic waste commonly found in urinals. The corrosive nature of this waste can lead to the deterioration of the brass, resulting in leaks and potential plumbing failures.

In contrast, other materials such as ABS, cast brass, and cast iron are generally more durable and resistant to corrosion. ABS (Acrylonitrile Butadiene Styrene) is a type of plastic that is commonly used in plumbing for its good chemical resistance and lightweight properties. Cast brass is known for its strength and durability, making it suitable for environments where it may be exposed to harsh substances. Cast iron is also highly durable and resistant to corrosion, making it a common choice for plumbing fixtures.

Understanding the properties of these materials is essential for ensuring the reliability and longevity of plumbing installations, particularly in high-use areas like restrooms.