Pressure and vacuum relief devices will be the same as those that are currently found on gasoline-style transport takers. Nearly all of these fuels are bottom loaded and unloaded by the standard 4-inch quick connect or direct connections. Valving is internal to the tanks with breakaway piping and remote shut-off controls. Vapor recovery systems, also known as scully systems, will be the same as those currently found on gasoline tankers (see Figures 3.5 and 3.6).