Is cellulose wadding easily inflammable?

One cannot compare how paper and cellulose wadding behave in fire. Indeed, paper will burn whereas wadding will smolder.

Cellulose Wadding is treated with boric compounds (boron salt) that release water under the action of very intense heat and have a combustion retardant effect.

In case of fire, cellulose wadding behaves like wood. A thick layer of carbon develops over the surface of the insulation the minute it is in contact with flames. This coal being a very bad heat conductor, it protects the cellulose against important warm-up.

Another key element is the poor thermal conductivity of cellulose which stops the high temperatures within the flaming region from passing through the wall too quickly.

The low air permeability and inertia of cellulose wadding also make this behavior possible.

Last and unlike glass wool, cellulose wadding does not liquefy and emits very little toxic gas.