No. 18 - Materials Used as Cigarette Tipping Papers Having a Perforated Zone - Determination of Unit Air-flow and Permeability
This method was replaced by the CRM No. 40 (now also obsolete).
CRM 40 - Determination of Air Permeability of Materials used as Cigarette Papers, Filter Plug Wrap and Filter Joining Paper including Materials having an Oriented Permeable Zone (October 1994)