Making a mess of glass and mystery liquid.

Correct. There are two types of dry systems. Both are there to prevent freezing up. The first system uses a clapper valve held shut by the air pressure in the system, a drop in air pressure springs a clip operated by a diaphragm... The other dry system is a deluge system, this is dry but doesn't have any sprinkler plugs or glass. The water flows out of all the heads at the same time. The detection is via smoke detectors and two of them have to operate. It can be triggered manually to if needed but deluge is only used in area's of large fire risk when water is safe to be used. They are very few deluge systems about as in high risk area's like flammable petrol etc its normally foam. Hope that is of help :)

The fluid is either alcohol and water or glycerine and water (depending on the quality of the sprinkler) The fluid expands when heated and breaks the vial but the size of the air bubble is a buffer for the pressure so the bubble compresses easily until the air pressure meets the fluid pressure, then the pressure rises until the glass vial breaks.

evilution

Yes, most buildings have a dry riser for their sprinklers. It makes the yearly system purge easier. I got sacked from a job because I let the sprinkler purging company come into the warehouse I was managing. They took the cap off the dry riser without turning the pressure off. There was a rush of air for about 10 seconds and then a solid sideways column of water about 12 inches in diameter shot out and destroyed thousands of pounds worth of carpets. The sacking was a ploy to get me to go and be a manager at a different store as they had problems filling the role for the wage they were offering. I had a new job with a different company the next day but told the other company that I would start and kept pissing them around for weeks before they realised I wasn't going to turn up.

evilution

Odd. I would have thought that would make things more complex, but I suppose it stops the water going nasty inside the pipe. I wonder if it's anything to do with the possibility of pipes freezing in unoccupied homes.

Big Clive

All of the sprinklers in the condos I’ve been in are dry systems with compressed air in the piping behind the head’s o-ring seal. When the air is released after the capsule pops, the sudden loss of pressure triggers the valve that starts the water. Not sure if that’s just to reduce maintenance and keep the system clean or if it’s not designed to be holding back water all of the time (of cause condensation, slow leaks, etc). Slow air leaks were just topped up with an air compressor so only a fast drop caused the water to flow.

The Griffiths Family

The most I could find was "non-toxic proprietary glycerin solution" for the bulbs.

CasualKitty

That would actually be pretty cool, Ive been wondering about that since ave made that vid

Clive - do you have a more-than-usual power laser? A fun thing to try in a future video would be to see if you can get the laser to heat up and break the capsule at a distance to test AvE's theory.

Benjamin Hall

Hi Clive, I work in the life saving equipment industry (smoke ventilation/window control systems). Velux had a primitive smoke vent which uses one of these vials to release a firing pin which then pierces a CO2 bottle, driving the window open quickly, it's a more exciting reaction to watch as its quite violent! If I am servicing one soon I will record the test and upload it.

The Tinkering Shed

Remote...oh That's just nasty.

Michael Thompson

Hi Clive! We have the recessed sprinklers installed in our home here in California. While I don't want to tear them out of the ceiling (!) I've uploaded some photos for you here. Though there is not much to see... <a href="https://david.gloveraoki.net/sprinklers" rel="nofollow noopener" target="_blank">https://david.gloveraoki.net/sprinklers</a>

David Glover-Aoki

Great video...I always wondered about these. I used to live in a high rise apartment where occasionally someone would use these as a handy support for clothes line with predictable results.

Vaughn B.

Perhaps the strengthof the vacuum before letting liquid in is sufficient to set the size of the bubble?

I thought they just melted, cool to know that they actually pop.

Joelle Seguin

Thouse covered ones are used in large residential house(req in some areas in us where sqft is too large) and some smaller commercial installs for aesthetics.

Travis Kneale