How a Fire Sprinkler Works at 100,000fps - The Slow Mo Guys
Gav and Dan like learning and like fast things. In this episode, they learn about a fast thing.
A fire sprinkler that you can probably see above your head if you are watching this from your office when you should be working. Shame on you! Nah, just kidding. Watch more Slow Mo Guys at work!
Follow us on Instagram!

Filmed at 1000fps with the Phantom Flex 4K and 103,000fps with the Phantom V2511
How a Fire Sprinkler Works at 100,000fps - The Slow Mo Guys

  • The Slow Mo Guys
    The Slow Mo Guys

    In the replies to this comment i'll be taking names for the possum.

    • TheRandomGuy


    • Morgan Kenning
      Morgan Kenning

      Margery Boffin

    • does bruno mars is gay
      does bruno mars is gay


    • Boss Coins
      Boss Coins

      @Noxius ues

    • arozthebeast


  • Azerin Farah
    Azerin Farah

    “or 155... american things.. yeah”

  • Vinnie, Cousin of Vito
    Vinnie, Cousin of Vito

    American Things? Got To Love the Brits, well not really

  • Patron


  • blackmambagame

    They needed to put more pressure on the water

  • homesliceconnor

    Dans has the best planet earth voice

  • Satan

    I learned about them when i played Postal 2. When you get in jail, you could hold light and hold a match under them. They go off and the cell doors open :)

  • who?

    American things lololololol

  • Christopher H
    Christopher H

    Nice wisteria lads

  • Hal Jordan
    Hal Jordan

    I don' even know why this video got recommended lol. As a safety engineer, this sprinkler can not extinguisher the fire. Its purpose mainly to supress down the fire. And the outlet pressure of sprinkler needs to be always at 100 psig.

  • Ricardo viana
    Ricardo viana

    Flint lockwood where are the burgers?

  • Micah Nightwolf
    Micah Nightwolf

    I like how the slow-mo makes it look like Dan sat there and face-tanked a heavy stream of water for a full ten seconds before eventually deciding to slowly duck out of the way.

  • Agc2749

    Now imagine when one of these bad boys pops with system at 100psi and your trying to wrap up all the trim before leaving the jobsite...stupid apprentices.

  • Rebecca Zappe
    Rebecca Zappe

    I need to show this video to my students to help them understand why they shouldn't throw balls inside or anything that could accidentally hit one of these. Break that glass, and it's all over 😱

  • Rogier van den Berg
    Rogier van den Berg

    I'm just going to say "American things" for all the stupid units they use

  • Richard Moye
    Richard Moye

    You guys should do a follow-up with a metal link type sprinkler

  • Mobil3g3nocid3

    I was worried they would not bust out the phantom lol

  • money

    And the people with headsets died 4:21

  • Ossian Haufe
    Ossian Haufe

    Was it with the maximum possible water pressure? How much water pressure you used?

  • Adventure Story
    Adventure Story

    Actually this fire sprinklers are working with higher pressure! If you like to see the real spray effect! For sure it will be different.

  • Michael G
    Michael G

    It's great design until you realize you can't turn them off, and you get more damage from flooding than fire.

  • Milky Moon
    Milky Moon

    The flowers behind them at the end were so gorgeous and magical!

  • Greenery games
    Greenery games

    This channel is the only one I know that has the best camera quality

  • ww1942digger

    At 3:45 Dann says the metal ping will drop out after the red pin has been distroyed by the heat of the fire. Ehhh no the metal pin doesn't fallout it will be puched out by the water pressure. And 99.9% in the movies they all go of in the picture witch it doesn't only the sprinkler that has been touched by the heat will be activated. Not so nice thing is the water will stop by setting of the waterpumps of the building most likely by the fire brigade. And the give a lot of water damage. But nice video cool to watch it in slomo

  • алексей гавр
    алексей гавр

    нахуя под сплинкером сидеть? ДБ... а в остальном вполне зрелый контент

  • Ex Mil in MA
    Ex Mil in MA

    Very nice lilac

  • Acklord

    I always thought that spiky thing spun lol.

  • DarkVitamins

    0:35 Minor nitpick: Heat doesn't rise per say, hot air does.

  • Will Da
    Will Da

    "ampoule" literally means lightbulb in french 7:00 **laughs in frog baguette* no it's not xDD

  • Iam Ben by the way
    Iam Ben by the way

    That one exploded fast but in other videos tooked minutes... 🥴🔥

  • Doctor Strange
    Doctor Strange

    Will a droplets of Water wash out a Fire 🤣

  • Fynn Bauer
    Fynn Bauer

    I from Germany and i musst watch the Vidio For homescooling ...

  • Dylan o bruhs
    Dylan o bruhs

    Cool video

  • Dylan o bruhs
    Dylan o bruhs

    I saw one of these go off in person but I wasn’t unlucky because I want to travelers insurance for a testing site

  • insectbah

    One of my favorite videos because 1) learning 2) Dan making a noise every time is hilarious 3) POSSUM

  • crow with a steak knife
    crow with a steak knife

    aren't we gonna talk about how perfectly alinged his screams are with the water at 1:19

  • Andrew Church
    Andrew Church

    Who would win? 1. A deadly hot chemical reaction that can bring down a building in less than a day 2. One sprinkly boi

  • Players Central
    Players Central

    Can the broken glass hurt you

  • Olivia Lashay
    Olivia Lashay

    Love y’all non Americans lol

  • Ozil Gzbsj
    Ozil Gzbsj

    The inexpensive refund feraly ask because crack cephalometrically cheat unlike a sleepy mask. automatic, dashing schedule

  • gogetthegoose1

    "American things"? .... unamusing!

  • Zxilks YT
    Zxilks YT

    I knew how sprinklers worked before this but I just wanted to watch it in slowmo

  • Everything Jeepster
    Everything Jeepster

    They’re called freedom units.

  • Alan Johnstone
    Alan Johnstone

    the real deal has a lot more water pressure in the system. I know from my own experience in property management.

  • Phil Nolan
    Phil Nolan

    Time to call BS on every movie and tv program that shows all the sprinklers going off at once.

  • Jan Jančík
    Jan Jančík

    I liked how he flexed with his FLEX 4K. Flexing is *tight* !

  • happydoggs

    Would be cool to see one burst at the actual 200psi most fire systems are charged too.

  • FectacularSpail

    Who the heck are these 2.6k people who don't like this? Do they have something against possums?

  • Shadman Shahriar
    Shadman Shahriar

    Disappointed. Fire sprinkler doesn't sprinkle fire.

  • Pc dude14
    Pc dude14

    Also it’s not glycerin it’s mercury

  • Hans Johnson
    Hans Johnson

    So the way that these are normally deployed , the pipes are dry and pressurized with air at around 45 psi (3 bar). This air pressure is holding a valve closed that is holding back water at about 120psi (8 or 9 bar). The ampule breaks, releases the air out. At around 20psi, the flapper valve flies open, and the system fills with water at street pressure. They spray a lot further when they go off.

  • Filipi E.S
    Filipi E.S

    0:55 "155 American...things.'' almost spat out the food I was chewing lmao

  • Zeta Alpha
    Zeta Alpha

    We all say Fahrenheit but we all mean ‘american’

  • Hotelogence Gaming
    Hotelogence Gaming

    Gav. Possums aren’t cute. Reguards, Ian.

  • Hayden

    I thought I’d see a high-pressure one

  • A Random Youtuber (EastwardNest784)
    A Random Youtuber (EastwardNest784)

    Noob: it water garden! Pro: no it’s to put out fire. Noob: no it water garden! Pro and me: no! Now SHUT UP NOOB!

  • Egemen Artuk
    Egemen Artuk

    4:19 is what you came for. You are welcome

  • pixeley87


  • Elenesski

    HAHAHAHA ... you made my day with the line "155 american things" :)

  • Roofluffer

    needs more water pressure i think

  • stiffcookie

    Slow Mo Guys: "A fire sprinkler that you can probably see above your head if you are watching this from your office" Everyone: Looks up

  • Domingo Coralee
    Domingo Coralee

    The unusual crayon electrophoretically empty because okra morphometrically contain onto a shallow mimosa. ancient, common unshielded

  • Slice of Sparta
    Slice of Sparta

    Hello! Engineer for a company that makes sprinkley bois here! I loved the graphic that popped up at 0:52 about the colors and temperatures. The "glassy, juicy ampules" (lol Dan) are called bulbs, and like the graphic shows, the color indicates the burst temperature. Several factors determine what temp bulbs you want to install, the main one being height. For example, the sprinklers at the top of a warehouse need to burst at a lower temp because of how far away the fire is, compared with a standard residential or office ceiling height. Sprinklers can also activate via "links", which are basically little plate springs that are held at tension by solder paste. The fire melts the solder, the spring explodes outward, water comes out. The explosive quality of the bulb or link is important, because you have to get everything out of the way of the water flow. Some sprinklers, known as nozzles, don't have anything holding the water back! More on that in a minute! One last thing: if you're in a building with a flat ceiling and don't see any sprinklers, look for round discs instead. These are known as coverplates, and they provide an aesthetically pleasing way to cover a sprinkler from view! They can be color-matched to any ceiling, and like links, contain a solder paste that makes them pop off and expose the sprinkler at a much lower temperature than would actually trigger the sprinklers. Couple of myths: first one was one I used to think before working here is that the round bit on the sprinkler spins around as it goes off. Sadly not true for any sprinkler! That bit is called the deflector, and it's specifically designed to spread water in a certain pattern. Deflectors vary based on many factors, but primarily where the sprinkler is installed and the orientation in which it's installed. Many hotels use sidewall sprinklers with very different deflectors than the one in this video. Another big one: sprinklers always have water immediately behind them in their pipes, like Gav and Dan's in this video. Also not true! SOME systems are like that, and those are basic wet deluge systems. The problem with them is that it's relatively easy to have an accidental activation, which is the SECOND worst thing a sprinkler can do, because water from sprinklers can cause lots of damage, but not nearly as much as a fire. The worst thing is obviously if there IS a fire and the sprinkler doesn't activate. All sprinkler companies go through GREAT measures to make sure neither of these things ever happen! Back to water in the pipes: systems that do NOT constantly have water behind the sprinklers are known as dry systems, and they rely on a trigger mechanism to open the VALVE on the water main that holds back water to the system. The trigger is typically one of three things: an electronic signal from a fire/smoke detector, a wet pilot line, or a dry pilot line. Pilot lines are located with the sprinklers in the protection area, and are pressurized with either water or air (wet and dry). When the fire trips the pilot line, the pressure on the line goes away, which trips the valve to open and converts the dry system into a wet system, but only nozzle sprinklers go off at this point. Most wait until the bulb or link sprinklers trip. Obviously the pilot lines trigger at a lower temp than the sprinklers; that way the sprinklers always have water behind them when they trip. Some valves have multiple of these fail-safes, to further ensure against accidental activation! Any questions? I promise I can either answer you myself, or get a nice, smart coworker to help me out! Hope everyone is having a great day! 😊

  • Rachael Stickle
    Rachael Stickle

    sprinkly boys lol

  • Casey Locke
    Casey Locke

    Stay away from the possum. That's a nocturnal animal out in the daylight. Something's not right.

  • Tom Hensley
    Tom Hensley

    I beg yous pardon, it anit right talking bout us mercians. Got got it citrus fruit. Lol

  • KimShea22

    Lol, got a Koorsen ad right before this video

  • AfroAsia Adventure
    AfroAsia Adventure

    155 American things 😂😂😂😂😂😂😂😂😂😂😂😂😂😂

  • avinotion

    7:14 The last one was my favorite

  • Chris Vecchio
    Chris Vecchio

    That's nothing compared to a real sprinkler head going off on a real system. I'm a sprinkler fitter. I've seen it

  • waffl3_ir0n

    1 like = 1 pet for possum

  • AnglingNVirginia

    Really cool, except for him acting like a 5 Y/O little girl about some water..

  • MaxMeh

    Excellent Sir David Attenborough impression.

  • yousef diaa
    yousef diaa


  • Joshua Bennett
    Joshua Bennett

    One actually installed in a building has much more pressure and has a pump connected to it of pressure isn't high enough they actually cover much much much more then what it shows in the video

    • Joshua Bennett
      Joshua Bennett

      The most common system is a wet system where the pipes are full of water but there is also dry systems where the pipes are full of air untill the heads go off then they fill with water

    • Joshua Bennett
      Joshua Bennett

      There's also several different types of sprinkler heads and systems this head is called a pendant because it's upside down and ones that are upright are called upright heads

  • John Rosenthal
    John Rosenthal

    The mindless intestine histochemically guide because song remarkably park near a lonely macaroni. nine, flashy millisecond

  • D

    The flex 4K is $100,000. I guess he’s really “flexing” on us.

  • Nova Prime
    Nova Prime

    Celsius? I'm American i measure temperature in apple pies, 10 meters? You mean 15 dog tails.

  • David Eldyn
    David Eldyn

    Video starts at the 5 min mark

  • Aram Zero
    Aram Zero

    That glass could potentially hurt whoever is under that thing tho. Even just if it goes in the eyes!

  • Eween Mj
    Eween Mj

    These shots are making me thirsty

  • much gameness
    much gameness

    Imagine in 15 years when we can get this kind of slow motion on a phone.

  • Eric P
    Eric P

    "155 aMeRiCaN tHiNgS" Wow 😑

  • TheCrafter1952 Official
    TheCrafter1952 Official

    "One hundred... Fifty-Five... 'American Things'." Technically the truth!

  • maddoxXL101

    As someone who used to test these kinda sprinklers you obversions are very accurate as to how the over head sprinkler works lol

  • Chris Moore
    Chris Moore

    The bottom of the sprinkler is called the deflector and the bulb pops and the whole brass seat falls out. And no they all don’t go off like they do in the movies just where the fire is that sets the sprinkler head off. I’ve been installing them since 07.

  • DoctorX17

    Fun fact: this isn't the only design for sprinklers! There are some that aren't one time use, but this style is by far the most common. The only "flaw" is that you can, y'know, break the ampule with physical force, but that takes more than a slight bump. Usually something more like someone doing cartwheels and kicking it or something silly like that.


    2020!!! covid-19!




    u guys have cool camera's

  • Fahad Naqvi
    Fahad Naqvi

    Please make video on how much time eye takes in getting reaction when something sand type hits in eyes

  • MisterSoul2008

    Now you have the meadow full of broken glass.

  • Sentauri

    life hack: set play speed to 0.25

  • Wing Man Au Yeung
    Wing Man Au Yeung

    Sprinkler head opens at 68 degree Celsius. Water pressure is needed to show the right spray pattern. Show intelligence, not dumbness

  • Smoke

    Watching in 2160p 60fps

  • Timer Twinkler
    Timer Twinkler

    I just noticed higher fps means something is going slower then low fps.

  • Lord Matthew
    Lord Matthew

    Its like iv never seen a fire sprinkler before

  • James Perkins
    James Perkins

    Didn’t know there where opossums in the UK.

  • Michael Gentile
    Michael Gentile

    I thought the gear like thingy spun.. I'm kinda disappointed now..

  • Gh5rd5 Playzz
    Gh5rd5 Playzz

    5:16 is the ultimate crack of the red glass