According to the Uniform Plumbing Code, the horizontal wet venting of sinks or floor drains by means of a common waste and vent pipe, adequately sized to provide free movement of air above the flow line is ____.

According to the Uniform Plumbing Code, the horizontal wet venting of sinks or floor drains by means of a common waste and vent pipe, adequately sized to provide free movement of air above the flow line is ____.