overall technology / combustible gas / gas burning fireplaces / machinery / gas burns / calibration gas / non-catalytic metal / typical chemicals / predictable final product / methane gas / gas detection equipment / gas molecules / metal oxides / butane gas / oil / gas passes / chemical properties / gas sensor / catalytic gas sensor / suitable metal oxides / catalyst chemical / chemicals / gas mixtures / higher carbon content gas / gas molecule / chemical media / gas readings / /