burning fast, not blowing up — combustion with a bad attitude but no shockwave.
means a chemical reaction that spreads via heat transfer through a substance slower than the speed of sound, unlike a detonation which is a supersonic shockwave.
from from latin deflagrare, to burn down completely — the de intensifying flagrare, to blaze, the same root that gives us conflagration.
gunpowder combustion — propels bullets by rapid deflagration, not detonation, in the barrel
texas city disaster 1947 — ammonium nitrate deflagration preceded the catastrophic detonation that killed 581
fireworks displays — regulated worldwide as deflagrating, not detonating, pyrotechnic devices
dust explosions — grain silos deflagrate then sometimes escalate into full detonation