A venting system of a single-wall metal pipe shall be sized in accordance with one of the following methods and the appliance manufacturer's instructions:
- For a draft hood-equipped appliance, in accordance with Section 803.0.
- For a venting system for a single appliance with a draft hood, the areas of the connector and the pipe each shall not be less than the area of the appliance flue collar or draft hood outlet, whichever is smaller. The vent area shall not exceed seven times the draft hood outlet area.
- Other approved engineering methods. [NFPA 54:12.8.5(1)]