Which of the following is NOT a requirement for common venting of multistory systems?

The requirement for common venting in multistory systems is that venting must be appropriately planned and executed to ensure safety and efficient operation of the appliances involved. One of the key aspects of common venting is ensuring that the system accommodates the specific needs of the appliances utilizing the vent.

The option that identifies oil appliances must be included is not a requirement for common venting systems. This means that in systems that might include multiple fuel types, such as gas and oil, it is not mandatory for oil appliances to be part of a common venting system. Instead, the focus is on ensuring that all appliances connected to the vent are compatible and that each type of appliance meets its unique requirements for venting.

Other requirements for common venting include proper combustion air sourcing, whether from outside or from separate areas that do not compromise air quality, and ensuring that venting runs are vertically aligned as much as possible to facilitate proper airflow and venting efficiency. These factors contribute to the safe functioning of multistory venting systems, distinguishing them from the inclusion of oil appliances, which is not a universal prerequisite.