According to the CDL manual, what three factors determine how much liquid a driver can load into a cargo tank?

AAMVA CDL Manual, Section 8.2.7, p.8-8-2

Overloading a tanker with a dense or expanding liquid can push the vehicle over legal weight limits or leave no room for the liquid to expand, both of which create real safety and compliance risks. Knowing these three factors helps a driver judge a safe, legal fill level before ever pulling onto the scale.