Over the past seven years, the Gas Technology Institute (GTI), the American Petroleum Institute (API) and the United States Minerals Management Service (MMS), have co-sponsored an extensive natural gas sampling methods research program at the GTI Metering Research Facility (MRF), located at Southwest Research Institute (SwRI). The results of this research provided a basis for the revision of Chapter 14.1 (i.e., Collecting and Handling of Natural Gas Samples for Custody Transfer) of the API Manual of Petroleum Measurement Standards (MPMS). The revision is complete and was published in 2001