A tourniquet is not just for bleeding injuries, they can also be used for crush injuries. According to a recent article by Vice News :
On January 9, 2018, a 7.6 magnitude earthquake hit off the Honduras in the Caribbean. The Daily Mail UK reported that the quake was one of the largest to hit the region in recorded history. Earthquakes can cause buildings to fall apart into piles of rubble killing the occupants. If a persons head, torso, or other vital area is crushed death is immediate or imminent. However, if a arm of leg is crushed the survivor has a chance. Applying a tourniquet to a limb above the site of the crush injury prevents the septic limb from infecting the rest of the body. If a tourniquet is not applied, the septic toxins will invade the body and kill the survivor. Knowing how to apply a tourniquet can also be the difference between life and death for crushed limb injuries then.
Step One: Identify the wound, in this case a crushed limb. Place the Tourniquet above the wound 2"-3" (5-8 cm) and or as high and tight on the limb as possible. High and tight is generally recommended for non-medical personnel who don't have tourniquet training.
Step Two: Form a closed loop by placing the free end of the tourniquet through the opposite end which should have a buckle or ring. Pull as tight as possible and secure.
Step Three: There are a few TQ types so add the compression needed by either:
a. Twisting the windlass bar at least 3 full turns or until occlusion pressure is reached.
b. Lift the ratchet lever to move the ratchet along the ladder strap until occlusion pressure is reached.
c. Wrap the elastic band around the limb as many times as needed until occlusion pressure is reached.
Note: A properly applied tourniquet is going to hurt, but you won't die, so that's the silver lining.
Step 4: if possible evacuate to an emergency room asap. Re-asses the tourniquet periodically to ensure it has not lost compression and is still working. Again a properly applied tourniquet will hurt, and if bleeding, the bleeding should be controlled. If you can reach your distal pulse (pulse below the tourniquet on the limb applied) palpate to ensure you have eliminated the distal pulse. Failure to eliminate the distal pulse may lead to complications such as compartment syndrome.
Search online for a bleeding control course near you for official accredited training or check out OMNA's training page for links to training companies in your area.