(edited 7/25/14 CEB) The intent is to revise the scope of ASTM D1709 to allow dart weights above 2 Kg for both test methods A and B. Improvements in polymer performance and availability have resulted in plastic films with impact resistance greater than 2 Kg. A task group within subcommittee D20.19 was set up to discuss potential technical issues around the use a heavier darts and determine what weight limits, if any, should be included in this standard. Consensus was to move ahead with a weight increase to 6Kg. Modifications to the test apparatus to use a heavier dart are likely minimal, but may need to be defined in future revisions of the standard. This revision is also necessary to address a contradiction with the requirements of ASTM E1745-11 Standard Specification for Plastic Water Vapor Retarders Used in Contact with Soil or Granular Fill Under Concrete Slabs. Performance class A as listed in Table 1 of that standard requires a minimum Impact Resistance of 2.2 Kg (which is above the current 2 Kg maximum). There are also ongoing discussions around defining allowable dart head materials and surface finishes, but it was also decided in committee to wait until completion of an ongoing ILS for that revision.
Keywordsdrop dart; impact; plastic film; Free-falling dart method; Impact resistance--plastics; Plastic sheet and film; Polyethylene (PE) sheet and film;