Are any of you aware of when the API Base Oil groups originated and how they came about? It seems that they originated around the same time as API SH and CD but I cannot find any history of who originated the five groups.
The API categorizes base groups in API 1509 Appendix E. That's available online if you search.
What's interesting is that the group designations are intended to give guidance to blenders and formulators for interchangeability in base stocks to ensure consistent performance, not as an overall indicator of finished oil performance. You see people on here constantly extrapolating the group designations of API 1509 Appendix E into some grand measure of "quality" but that is not the intended use. A finished oil is still more than the physical properties of the base stock.
As to when it came about I don't know. Perhaps the API could tell you when API 1509 Appendix E was first published.
Appreciate your responses but I must not have identified what I was looking for. The API base oil groups have been well defined and much written about them. But, what I am looking for is how and when they came to be called Grp I, Grp II etc. I do not believe that the early oil industry called the early solvent refined oils Group I oils. But some where they began to be called that, Was 1509 the original name assigner? Was the first issue of 1509 the first time base oils had been divided into these five groups? I assume it was done for base oil read across purposes AKA saving money in testing. I am older than most of you but I cannot recall discussions on how the various groups got their spots. Thanks again.
For the History of the API try:
The Story of the American Petroleum Institute, by Leonard M. Fanning, published in 1959, and
The American Petroleum Institute: An Informal History (1919 – 1987) by Stephen P. Potter, published by API in 1990
Alibris or Abe's book stores may have them.