Improving the Precision of the HFRR Lubricity Test

Researchers and cooperative groups worldwide conducted research and developed several test methods to gauge the lubricity of diesel fuel. This was necessary because the more recent fuel specifications require a higher level of hydrotreating which in turn can result in a reduction of diesel fuel lubricity. An appropriate test method was needed to enable measures to restore fuel lubricity and to enable fuel suppliers to comply with the newly adopted diesel fuel lubricity specification.The current test method that is used by most regions of the world is the High Frequency Reciprocating Rig, HFRR. Although this test method was developed and selected by the ISO group originally, and is fundamentally the same, it has been adopted in slightly different forms by regions of the world. One common element in all forms of the test method is its poor precision when compared to test methods for other fuel properties.In an effort to identify sources of variability in one version, ASTM Test Method D 6079 (1),* a workshop was conducted in which seasoned operators observed, discussed, tested, and provided recommendations to improve the existing version of the test method.This document will provide details of this project along with statistical analysis of the test results. It identifies the relevance of several parameters and practices and their effects in reducing test method variability.