National Air Duct Cleaners Association (NADCA) Practice Test

Containment barriers isolate the cleaning area to prevent cross-contamination. For this to work effectively, barriers must stay intact, sealed, and used consistently; entry points should be controlled and doorways kept sealed unless access is required. When barriers remain closed and properly sealed, contaminants cannot migrate into adjacent spaces, and the airflow can be managed to keep dirty air from leaking out. Controlling who can enter and when helps prevent bringing in new contaminants and minimizes disturbances that could breach the seal. Consistency is key—if the barriers are sometimes open or misused, the containment loses its protective purpose, increasing the risk of spreading dust and debris during and after cleaning. Keeping inner areas sealed as well as the outer boundary ensures all targeted spaces stay isolated throughout the entire process.