Can solid and gas fixtures be vented together according to code?

According to plumbing codes, solid and gas waste fixtures cannot be vented together primarily due to the need for proper venting to maintain the system's integrity and prevent backflow or potential odors from entering living spaces. Each type of waste has different venting requirements and behaviors; solid waste typically needs more ventilation to ensure effective drainage and prevent clogs, while gas waste may require more specific vent lines to handle gas pressures and prevent the gases from escaping into the environment.

When solid and gas fixtures are vented together, it could lead to insufficient venting for one type or the other, creating risks such as blockages or the buildup of harmful gases. Additionally, plumbing codes are structured to prioritize health and safety, meaning that combined venting could potentially violate these principles, leading to hazardous conditions. Thus, the response that they cannot be vented together aligns with standard plumbing practices and regulatory codes.