Abstract: A roll-form building material spacer product providing air space and drainage passageways within a building structure. The building material spacer has an openwork structure and carries an antifungal agent which prevents the growth of mold and mildew within a building structure in which the spacer is installed. Preferably, the antifungal agent is dispersed evenly throughout the openwork material either within the material or coated on the material. A building structure assembly having the openwork spacer and methods of making an openwork spacer and making a building structure with the spacer are also provided.

Abstract: A blast cleaning machine for pipes includes means for supporting the pipe in a horizontal position and for rotating the pipe about its axis. The machine also includes an enclosure mounted above the pipe supporting means and the enclosure has a lower opening which is positioned in use close to the upper side of the pipe. A centrifugal blast wheel receives abrasive from a hopper and blasts the abrasive in a downwardly inclined direction through the opening and on to the pipe surface. The spent abrasive rebounds from the pipe surface into a conduit by which the abrasive is conveyed to a reclaim zone in which the abrasive is separated from dirt and other foreign matter and is then returned to the hopper for re-use. The machine can be adjusted for cleaning of pipes of different diameters and in the region of the said lower opening there are interchangeable components by which the size of the opening can be varied according to the pipe diameter.