The effect of foam layout on NO emission inside a a porous burner with three porous media layers has been experimentally studied. The experimental set-up included two zones, combustion and preheating. At the combustion zone, there are five layers of porous media with different pore densities; at the preheating zone, there are alumina spheres as porous media. Numerical solutions show that permutation of porous foams with different pore densities has an effect on emission rates. The purpose of this experimental study is to investigate effect of porous media permutation and equivalence on emission rates. Results indicate that when the foam density is decreased from combustion zone to exit, NO emission is declined.