API MPMS 8.3:1995 pdf download.Manual of Petroleum – Measurement Standards Chapter 8-Sampling
6.2 CONTAINER SIZE
A general rule is that both primary and intermediate con- tainers should be large enough to hold the required sample size within 80 percent of the total capacity to facilitate mix- ing and to provide for thermal expansion. The size of primary containers is determined from the sampling operation as outlined in Chapters 8.1 and 8.2 of API’s Manual of Petroleum Measurements Standards. The size of intermediate containers should be as large as practical to minimize surface tension effects with due con- sideration given to storage space requirements, shipping rules and regulations, costs, availability, and other practical considerations.
6.3 CONTAINER MATERIAL
Sample containers are normally made of glass, metal, or plastic. Care must be exercised in selectin of container ma- terial, as it could affect the test results obtained from the sample. Containers acceptable for samples to be tested im- mediately may not be acceptable for storage of samples. Glass containers are suitable for many sample test and storage requirements. Clear glass bottles may be examined visually for cleanliness and allow for visual inspection of the sample for free water or solid impurities. Some petroleum samples are affected by exposure to sunlight if clear glass is used. In these cases, brown glass bottles may afford the nec- essary protection. Cans made of tin must have seams that have been sol- dered on the exterior surfaces with a flux of rosin cleaned in a suitable solvent. Such a flux is easily removed with gaso- line, whereas many others are very difficult to remove. Minute traces of flux may contaminate the sample so that re- sults obtained on tests such as dielectric strength, oxidation resistance, and sludge formation may be erroneous. Care must also be taken to ensure that samples containing free or entrained water are not corrosive to the metal. Internally epoxy-lined tin cans may have residual contamination and precaution should be taken to ensure its removal. Cans made of stainless steel with welded seams are suit- able for many sampling operations. Other than ensuring the cleanliness, use of these containers presents no unusual con: cerns. Plastic bottles must be of a material that is impervious to attack from the sample. This is especially a consideration when using plastic for long-term storage of certain petroleum products. Clear plastic bottles are unsuitable for samples sensitive to light. When sampling aviation fuels, ASTM D4306 should be consulted for guidance on container selection. This standard gives information on the types of containers that have been found satisfactory for tests to determine water separation.