A Fire Bucket is filled with sand or water and is used to extinguish fires. Sand is often used where there is a risk of spilled flammable liquid which might ignite and spread by flowing across the ground. The sand is deployed to act as a barrier so it can stop flowing liquid. Sand fire buckets are used on Class B fires.
Water filled fire buckets are sometimes used where a water extinguisher might not be convenient, or where a supplement is prudent. Water fire buckets are used on Class A fires.
Want to learn more about the history of the fire bucket? If so check out this fascinating page into their history by H&O Plastics here.