On Fri, 18 Aug 2017 03:14:02 GMT, Iggy
m wrote:

replying to clare, Iggy wrote:
Very simply, the seams aren't air-tight and therefore not fire-tight. As
proven by the nightly news (see YouTube). Story upon story of this building
and that home burned down to the ground in less than 30-minutes...what
drywall's rated for and easily capable of retaining a fire for. But, even the
ASTM won't correct its decades-old error in The Code...I've tried for almost
15-years. If you haven't seen my posted-today list, Vertical Installation is
so good that it's not required to be taped and mudded and is at its full level
of fire protection upon installation.
PROPERLY mudded the joint is as fire resistant as the rest of the
drywall. What the stories don't tell is in many cases there is no
"fire blocking" so when fire gets behind the drywall it's like a
blowtotch. No difference between horizontal and vertical.