Hand railing codes can vary from county to county in any one single state. Most ADA ramp railings require that the grab rails be between 34 and 38 inches in height where as the Guardrail be a minimum of 42 inches. There are certain exceptions to the rule but for the most part the majority of cities and counties will at least foolow the federal guidelines for handicap access.
Most ADA steel handicap railings for exterior use will have one thing in common, that is a break leveling out at each landing. The minimum length for each break may varies depending on circumstance of the stair, ramp or condition that that is. The standard minimum is 12″ from edge of the top step back toward the landing that is level.