A type "B" gas appliance is an appliance, with gas consumption in excess of 10 MJ/h, for which a "certification" scheme does not exist.
Note:
A type "A" appliance when used in an industrial / commercial application for which it was not intended is considered to be part of a type "B" appliance. An example of this is a certified direct-fired space heater used as the heating/ventilating device in a spray/bake paint booth.