How is sand useful for extinguishing fire?
It limits the supply of oxygen and it smothers the fire.
Sand that is free of flammable organic materials is helpful in extinguishing fires. Sand works like other extinguishing materials by absorbing heat and suffocating the fire by cutting down the oxygen supply. Sand is best used on small outdoor fires and cooking fires that are slow burning. It may need to be combined with water and spread around to smother flames and ashes.