Where any device having an open flame or surface temperature greater than 800°F (426°C) is used in an independent circuit, a hood and exhaust system shall be provided in accordance with Article 5, Exhaust Systems. Such exhaust system shall discharge combustion products to the outdoors.
Exception: A hood and exhaust system shall not be required.
1. Where the refrigerant is R-717, R-718m R-744;
2. Where the combustion air is ducted from the outdoors in a manner that prevents leaked refrigerant from being combusted.