Which of the following describes a requirement for venting systems in general?

Venting systems are crucial for safely directing combustion byproducts, such as gases and vapors, away from appliances and out of building interiors. One of the fundamental requirements for these systems is that they must not extend through air ducts. This is to prevent the contamination of the conditioned air that is circulated throughout a building. If venting systems were allowed to pass through air ducts, there could be a risk of harmful gases backdrafting into living or working spaces, posing a serious safety hazard.

Moreover, air ducts are designed for airflow and temperature control, whereas venting systems deal with exhaust and potential byproducts of combustion. Mixing these functions could lead to compromised efficiency of the heating or cooling systems as well as increased risks of exposure to harmful substances. Thus, ensuring that venting systems operate independently from air ducts is essential for maintaining indoor air quality and overall safety.