D3948_14_9

Under no circumstances shall test fuel be pre-filtered as filter media can remove the very materials, surfactants, that the test method is designed to detect. If the test fuel is contaminated with particulate matter, allow such materials to settle out of the fuel before testing. Special precautions concerning sample containers and sampling technique are discussed in Appendix X2 of the written standard. Extreme care and cleanliness are required in taking samples either directly into the test syringe or into a sample container. Before pouring the test sample from the container, wipe the container outlet thoroughly with a clean, lintless wiper; pour the test sample into a clean beaker or directly into the barrel of the test syringe. Test method results are known to be sensitive to trace contamination from sampling containers. For recommended sampling containers, refer to Practice D4306. If the sample for test is not within the test temperature limits, 18 degrees Celsius to 29 degrees Celsius (or 65 degrees Fahrenheit to 85 degrees Fahrenheit), allow the sample to stand until an in tolerance temperature is attained.