Red Seal Plumbing Practice Exam

Building sewers 8' or larger must use a manhole, which is necessary for access and maintenance of the sewer system. Vent stacks are vertical pipes that balance air pressure in the system and help prevent odors from entering buildings, but they are not specifically required for sewers of this size. Backflow preventers are typically used to prevent contaminated water from flowing back into the main water supply, but they are not directly related to the size of the sewer. Sump pumps are typically used to remove water from basements, but they are not necessary for sewers of this size.