Atleast once a month I have to get a jump due to my car alarm draining my battery. Why does this happen?
I assume you are looking at the head of a sprinkler system. Heat causes the liquid to expand and break the glass, this allows a valve to open and release the water. Your cigarette will not set it off. Modern fire suppression systems are what is called pre-action. Here there are smoke detectors (that your cigarette could set off). A control panel will alarm if a detector senses a fire. If a second sensor sees a fire then water is released into the pipework. Water will then be released from any sprinkler head that is opened by heat. This prevents water damage from false alarms. The pipework is often pressurized by air and a pressure switch detects the pressure loss if a sprinkler head is broken by accident. Edit, Sorry I don't know what the liquid is. I do know that the color indicates the temperature at which the head will release the water and that volatile liquids are used. I would guess there may be a few things used.
Oh, I'd love for it to snow I don't do electric blankets, (grin) trying to cut back on EMF's or maybe, I'm afraid that I'll channel the KLF and their ancients of mu-mu. I just pile on another quilt!
