Abstract: A process and arrangement for introducing a material such as a foam into automobile body cavities for at least one of noise insulation or increased rigidity. The cavities may be provided with open spaces or be adapted to only be partially filled with the foam. A bag is initially introduced into the cavity with the bag being provided with a filler opening. The volume capacity of the bag corresponds approximately to the volume of the automobile body cavity or a portion of the body cavity which is to be filled with the foam. A mixture of expandable components is introduced into the bag and, following an expansion reaction or a setting, the foam fully fills the bag.