Since before recorded history, human beings have likely been lighting stuff on fire just to see what happens. Thanks to the modern invention of the Internet and YouTube, now other people (outfitted with protective gear and schooled in safe-handling procedures) can light stuff on fire for you while you watch from the safety of your own home. Today’s sacrifice to the altar of fire: ammonia.
For most people, run-ins with ammonia probably involve either smelling salts, fish tanks, or the smell emanating from an unclean kitty litter box. Hopefully that’s the extent of your interaction with the chemical, as it can be extremely dangerous under the right conditions, as warned by the National Fire Protection Association’s label. As the above video shows, once ammonia vapor is ignited, it flows like an unstoppable river of fire.
What’s interesting here is that ammonia vapor is actually quite stable when it comes to flammability. The vapor must be preheated before ignition can occur; it also has an auto-ignition temperature of over 1,200°F, which is almost three times that of diesel fuel. The video is a controlled demonstration of what happens when ammonia vapor reaches its lower flammability limit (in other words, its concentration in the air at which it becomes flammable) of 15% and is then ignited using a high-energy source. The vapors are lighter than air but can initially hug the ground, perhaps explaining the undulating patterns of the flaming fluid as it flows out of the container. Ammonia is classified as nonflammable, but clearly it can burn under the right conditions, so those who come into contact with it on a regular basis need to know how it behaves. However, it’s not just potential flammability that makes ammonia dangerous.
Anhydrous ammonia is quite commonly used for refrigeration, chemical manufacturing, and as a component in fertilizer, so a lot of folks deal with this potentially lethal chemical on a daily basis. Despite the beautiful display of ammonia flambé seen in the video, the more dangerous hazards are frostbite, burns to the skin and eyes from the liquid, irritation of the skin and eyes by its vapors, and potentially lethal poisoning if inhaled. It’s nasty stuff, so it’s best not to mess with it unless your job requires it and you’re properly trained.
And if you think that ammonia and fire don’t mix, but that ammonia and water might be safer, think again.