  == Intro cleanup ==  I cut this sentence out of the introduction:   In the United States, federal safety laws require that window glass be tempered if each of the following criteria are met: sill height within 18 in (0.457 m) of the floor, top edge greater than 36 in (0.914 m) from the floor, area greater than 9 ft² (0.836 m²), and horizontal distance to nearest walking surface of less than 36 in (0.914 m).http://www.diychatroom.com/f19/when-tempered-glass-required-36117/#post214129  There are couple problems with that where it was.  It cluttered the intro and went into way too much detail on a particular tangent, interrupting the flow of reading.  Its inclusion in the intro such detail also places undue weight on this particular regulation in the US - also too much US focus.  That said, it is referenced and somewhat interesting, so it might fit somewhere else in the article - maybe in a new section on regulations requiring tempered glass in various applications... -  