Flammable Liquids and Fire Protection Standards

Here are two more:

DOT Pipeline and Hazardous Materials Safety Administration
http://www.phmsa.dot.gov/

Federal Railroad Administration
http://www.fra.dot.gov/

There are also State transportation and safety agencies that may impose their own requirements. Some of these post their regulations online.

You should also have a chat with your local authorities. Some of their representatives are very informative and helpful. Good luck.

Try NFPA 30.

This should help you.

At some point, this design should or will be reviewed by the "Authority Having Jurisdiction" (AHU). He will provide permission to construct and operate, or have authority to shutdown the proposed equipment. Try to carefully find out what needs to be done to make him happy with the installation.

Previous responses on NFPA, API and other resources are a good place to start.