A boiler which has a volume exceeding 120 gallons or a heat input exceeding 200,000 Btu per hour, or an operating temperature exceeding 210 degrees F that provides water to be used externally of itself is defined as a ____.

A boiler which has a volume exceeding 120 gallons or a heat input exceeding 200,000 Btu per hour, or an operating temperature exceeding 210 degrees F that provides water to be used externally of itself is defined as a ____.