google it. It's an oil density standard. Too much info to post here. Not sure about the BHP part but it is probably contained in the reference material.
Strass
Be courteous to all, but intimate with few; and let those few be well tried before you give them your confidence. George Washington
Register for free to join our community of investors and share your ideas. You will also get access to streaming quotes, interactive charts, trades, portfolio, live options flow and more tools.