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A-8 Figure A-6. Grips for the BAM test. Figure A-7. Weights for the BAM test. were examined microscopically to determine if the BAM test to an ASTM D638 Type I Dumbbell. This was done source of the crack could be identified. In almost every to open up the possibilities for the test to be performed on case involving post-consumer recycled (PCR) bottles unmodified stress-crack testing devices. (natural or mixed colored), the crack started at a piece The current version of this test takes some aspects of the of silicone rubber. Bam Test, with the exposure conditions of the FL-DOT test and uses a test specimen with a Fathead, so the test is referred to as the BFF Test. A.3.3 BFF Test (TRI Method) This test method was first used in these laboratories as a Test Specimen means for classifying the cracking resistance of post-consumer recycled HDPE for a commercial client. The BAM test (1) was The specimen is basically an ASTM D638 Type I Dumbbell much too severe, so a test was needed that could distinguish with a couple of modifications. First, a 7/32-in. hole is drilled poor stress cracking materials. The first tests were performed into each head portion so that the specimens can be mounted with the testing apparatus used for the BAM test, under the with a screw in a conventional stress-crack testing device. same 580 psi of load, but the exposure environment was However, because of the holes, the tabs on each side of the changed from a surfactant to D.I. water. This environment hole are narrower than the reduced section of the dumbbell. was inspired by the Florida Department of Transportation Therefore, the highest stressed areas are the tabs, so all the (FDOT) durability protocol, also performed in D. I. Water (2). specimens would naturally fail at the tabs. To get around this, The test worked very well at 580 psi, but it was changed to a 6in. square, open-faced mold was modified to produce 650 psi to match the FDOT testing conditions. And eventu- plaques that were about 45 mil in the center and over 90 mil ally, the test specimen was changed from the bar used in the on the edges. This way, the tabs are under less stress than the