It's an old trope, the hero needs to escape,
so she pulls out a lighter and trips the fire
sprinklers across the whole building --is
that just movie magic?
How do those things know when there's a real
fire around?
Howdy hotties, thanks for stopping by DNews!
I'm Trace.
Fire is one of the most serious disasters
facing human construction projects throughout
history.
Fires destroyed
Constantinople, Rome, Amsterdam, Toyko, Moscow,
London, San Francisco, Hong Kong, Chicago,
Singapore, Tianjin…
They can start anywhere and spread anywhere.
Fire Suppression systems are universal in
so many movies and TV shows, but according
to the National Fire Protection Association
all the sprinklers going off at once is absolutely
a work of fiction…
In the 19th century, textile mills began installing
"perforated pipe systems" which could manually
be flooded with water to put out a fire before
it got out of hand.
Then, in 1872 the first automatic system was
created, and was perfected two years later
by the owner of a piano factory named H.S.
Parmelee.
The system used heat activated material that
released the tension on a spring allowing
the water to flow -- and modern systems (dating
to 1889) pretty much do the same thing, but
today we use glass to hold back the water…
Because of this heat-activated bead, only
sprinklers subjected to hundreds of degrees
will spray water -- not every sprinkler everywhere.
If you look at a fire sprinkler today, you'll
likely see a tiny glass bead filled with liquid
or a color coded piece of metal -- called
a fusible link.
The beads are easiest to spot, and the color
of that bead tells you how hot the ceiling
can get before that sprinkler will go off.
These systems work with simple physics, inside
the bead is a glycerin-based liquid (sugar
alcohol) which expands when heated to a specific
temperature.
That expansion breaks the glass, allowing
what's in the pipe to flow!
A hotel or home goes up in flames more quickly,
and at lower temperatures, than say a factory…
so different buildings will have different
classifications.
Red beads break at the lowest temp of 135
to 170 degrees (57-77C)... and they're the
most common.
Intermediate levels are yellow or green, they
break at 175-225 (79-107C), and the highest
levels for warehouses or factories have black
beads which break at 650 fahrenheit (343C).
The thing is, what comes out of the sprinkler
doesn't just have to be water.
It can also be inert gas or foam designed
to snuff out really strong fires in sensitive
areas.
But, if it is liquid, there are two kinds
of suppression systems: wet or dry.
Wet systems have pipes filled at all times,
and dry systems have NOTHING in them until
a broken bead upsets the vacuum balance.
Dry systems are better for places where freezing
temperatures could damage the pipes, or perhaps
where a leak could seriously damage the building
-- like a historic site.
Now, I know I said otherwise, but there ARE
systems where ALL the sprinklers will turn
on at once.
They're called DELUGE systems and they're
used in places where huge fires could get
out of control quickly, like "power plants,
aircraft hangars and chemical storage or processing
facilities."
Not so much, office buildings… even fictional
ones run by spies.
So next time you're in a hotel, or you spot
a sprinkler head, remember, it's connected
to a massive system of pipes designed to keep
your building from fire harm!
You can nerd out about the color of the bead,
and scoff at every movie that uses the fire-sprinkler
trope.
You're welcome.
There are other ways to keep an eye on your
home too…
AT&T Digital Life smart home security helps
keep you connected to you home, so there are
no more what ifs.
If you're into crazy things about fire, AND
debunking movies -- you should learn about
how fire works in space… because again,
pretty much every movie is wrong.
Check out the OLLLLLD video 
about it here.
Wow. that hair.
What was I thinking?!
What else do you want to know about the world
around us?
Any other systems you want us to dig into?
#ASKDNews
