API RP 1637 Fourth Edition PDF
This recommended practice describes a system for marking equipment used to store and handle bulk petroleum, alcohol-blended petroleum, and biodiesel products. The equipment marking Color-Symbol system described in this recommended practice facilitates easy identification of products by means of colors, symbols, and alphanumeric designations. The principal purpose of this marking system is to identify product transfer points for tank-truck loading and unloading at distribution terminals and retail outlets to prevent errors in product handling.
The marking system described in this recommended practice does not cover aviation fuels.