There are “dry” systems where the water piping is usually filled with air or an inert gas (nitrogen) under pressure and a head must be activated to allow the air/nitrogen to fill the pipe and flow from the head. The loss of pressure in the system from a head causes a valve in the sprinkler riser to trip and provide water to the entire system, but the sprinkler heads still work individually.
“Pre-action” systems exist. The water piping is usually filled with air or an inert gas (nitrogen) and a valve must open to ”charge” the piping with water. In other words, the piping can fill with water (except for any air trapped in it) and water will flow from any individual head that is activated by heat. The valve that charges the system is usually activated by one or more heat or smoke detectors positioned within the protected area (smoke detector > valve activation > pipes fill but no water flows until heat activates one or more heads).
A “deluge” system uses sprinkler heads that are all open, but the water is held back at a system valve. Just like in a “pre-action” system, smoke or heat detectors (or other fire detection technologies) cause the valve to open and then ALL sprinkler heads start to flow water.
So…if you really need all the sprinkler heads to activate for your movie, you want a “deluge system.” Furthermore, you have to activate it by activating the associated heat or smoke detector(s), NOT an individual sprinkler head.
Also re: sprinkler system fiction vs. reality, I read somewhere recently (hopefully not here, that would be embarrassing) that on TV and in movies, when a fire sprinkler system accidentally goes off, the water that comes out is clean and clear. Sometimes the characters, after being initially surprised, kind of go with it and start dancing and cavorting around in the falling water, as if enjoying a nice Summer shower.
But in reality, since the pipes that feed the sprinkler system never get water flow (until they do) the water that would come out, at least initially, would likely be a disgusting brown sludge.
Let’s not forget the women having affairs with vampires in bad movies and books.
That’s how it went the time I got arrested (Illinois, early '70s).
Snicker.
Akagi, Kaga, Soryu… .
Guy I knew had one of those back in the late '70s. Took maybe four seconds to convert it from semi-auto to full auto, and one second to change it back. (I think they “fixed that problem” on newer models.)
Interesting. I haven’t been up close to a sprinkler head for 40 years, back then it was definitely wax plugs. (melb.aus). I’ve seen the eutectic links on fire doors.
That’s a significant advantage of dry systems. Tap water contains dissolved air, the oxygen reacts with the steel sprinkler system pipes. And every time you have to re-charge a wet system, it gets a new shot of air, so if there are leaks or failures, you’re continually playing catch-up.
I thought I remembered hearing stories about triggered deluge systems (and now that the word has been used, I remember the word), but I couldn’t remember or think of any examples.
The one I remember was related by Daniel V. Gallery. During WWII a group had gathered on the hangar deck to watch a movie. A sailor thought he’d prank them by holding a lighter on a long pole under a sprinkler head. It was not just the movie-watchers who got drenched (with salt water!).
He received a stern talking-to – or was thrown over the stern. I forget which.
X is murdered. Detective Q is on the case.Y is the obvious suspect. Y is taken into custody. Q is certain Y is guilty. Q intensely pressures Y to confess to the murder. A distraught Y maintains their innocence. After further investigation Y is cleared. Z is a friend of X. When Y is released an irate Z attacks, severely injures and/or kills Y. Q feels bad.
Here is one that’s probably been mentioned, but I just saw it on two different shows yesterday.
Taking lots of unknown pills. In one, a guy took a whole bunch of blood pressure pills from someone else, because he’d left his at home when traveling. No attempt to figure out a good dosage or anything, just take a bunch.
In the next show a guy is being offered some recreational pills, so he eats the whole bowl. I’m sure hilarity ensues, but that’s the next episode I haven’t watched yet.
I know such things as accidental overdoses exist, and people eating a whole browny when they should have had half a gummy, but does anyone who is not already way too high just gobble down a handful of random pills?