ASHRAE only gives a value for under a hood, so I think a hood will be required. The calculation of heat gain from the appliance is 130 btuh to the room per sqr feet of hearth opening. According to ASHRAE.
So a 3x4=12 sqr foot hearth opening will have a heat gain of 1560 btuh.
(ASHRAE rating for Oven (pizza) per sf of open hearth under a hood.)