This publication provides general information regarding the safe use and proper handling of liquid containers commonly used by industry and institutions. It is intended for users, shippers, carriers, distributors, equipment designers, installers, safety administrators, and all others desiring an introductory knowledge of liquid containers. It is intended to complement national, state, provincial/territorial, municipal, and insurance company safety requirements. The information in this publication applies to pressurized insulated liquid containers including U.S. Department of Transportation (DOT) DOT-4L portable liquid storage pressure vessels with a maximum water capacity of up to 1000 lb at service pressure from 40 psi up to 500 psi and Transport Canada (TC) TC-4LM portable liquid storage pressure vessels up to 550L at service pressure from 0.3 MPa up to 3.5 MPa.