- Obtain 35 feet of printed pool film wound on a suitable core. The sample should be taken in a way that minimizes stretching or pulling.
- Do not use any film sample which is noticeably narrower or wider than the rest of the roll.
- Label the sample with spec., lot and roll number.
- Within five (5) minutes, roll the sample out on a layflat table and mark it at the 0 and 25 feet (300 inches) marks previously established on the table.
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Note the time and write in on the sample.
- Cut off any excess material that overhangs the end of the table.
- Do not pile more than four (4) samples on top of each other.
- Wait 24 hours; measure the total distances in inches that the pen marks on the sample have moved from the 0 and 25 foot marks.
- Calculate the % snapback as:
(Total decrease of length in inches/300)x100
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