Abstract: A self-supporting filter element is produced from a precursor fiber web according to one of several methods. The precursor fiber web contains heat-shrinkable fibers or binder fibers or both. The web is exposed to temperatures sufficiently elevated to cause shrinkage of the fibers or melting of the binder. After cooling the web, the filter elements produced are self-supporting, and may have densities up to 500 kg/m.sup.3 to improve filtration while retaining good functional characteristics for operating pressure drop and air permeability. The self-supporting filter elements can be constructed of one material, and thus may be suitable for recycling.

Abstract: A pesticidal barrier, which may be used as a liner for a building excavation to protect the building to be constructed from infestation by termites and other insect pests, takes the form of a flexible membrane. The membrane comprises an assembly of fibers or filaments. The assembly has an average void volume of less than 85% when measured under a pressure of 10 kPa (1.45 psi). The fibers in the assembly have an average fiber size of less than 6 denier. The assembly integrally incorporates within its structure, or has above or below its structure, an array or network of connected permeable-walled tubes, so that an insecticide may be delivered to all parts of the membrane, particularly after the barrier has been installed at a building site.

Abstract: A rigidized fiber filter element is produced from a precursor fiber web. The precursor fiber web contains heat-shrinkable fibers or binder fibers or both. The web is exposed to temperatures sufficiently elevated to cause shrinkage of the fibers or melting of the binder. After cooling the web, the filter elements produced are self-supporting, and may have densities up to 500 kg/m.sup.3 to improve filtration while retaining good functional characteristics for operating pressure drop and air permeability. Rigidized fiber filter elements can be constructed of one material, and thus may be suitable for recycling.

Abstract: A pesticidal blanket, which may be used as a liner for a building excavation to protect the building to be constructed from infestation by termites and other insect pests, takes the form of a foraminous, fibrous membrane. The membrane comprises an assembly of fibers or filaments. The assembly has an average void volume of less than 85% when measured under a pressure of 10 kPa (1.45 psi). The fibers in the assembly have an average fiber size of less than 6 denier, and are coated with an insecticidal substance when the pesticidal blanket is installed at the building site.