with up to about 1 8 inch 3 to 4 mm of open space between adjacent strands of polypropylene accordingly a large number of dry ice pellets will pass through the open spaces in the secondary backing layers and immediately begin to break apart the primary layer of binder material in addition as noted above the stripping operation which is used to pull out the pile fibers especially if a stripping operation is used with a series of stripping rollers will cause further breakage loosening and removal of any remaining binder material this may be especially effective if the binder material remains cold and brittle accordingly preliminary tests on used carpet samples have indicated that in at least some carpet segments a single blasting operation is sufficient to allow relatively thorough decompiling of the carpet during testing operations carried out to evaluate this system the dry ice pellets tended to disintegrate as soon as they smashed against the carpet and provided no opportunity for recycling the dry ice except possibly for collecting carbon dioxide vapors and refreezing the vapors to generate more dry ice however depending on the pellet size and other operating parameters of a specific system a system which uses dry ice blasting can provide for collection and recycling of dry ice pellets if they remain intact after they have impacted the carpet in.