The figure calls it an imaginary line, but it is not imaginary. It is really only "imaginary" with respect to becoming a whole lot line, since it's not a lot line. But the gap that determines exterior wall hearth-resistance ratings and allowable opening percentages relies on the gap to this https://seecontainer-kaufen57778.wizzardsblog.com/36595836/rumored-buzz-on-ibc-container-zubehor