BTUs, or British Thermal Units, are influenced by various factors in your gas setup, not just the burner itself. These include gas line pressure, pipe size, length, and valve system, which collectively determine the BTUs supplied to the burner.
Our burners typically have a rating of 600,000+ BTU, yet actual delivery depends on your setup. For example, if you only deliver 65,000 BTU to the burner, your flame will be at 65,000 BTU. The more BTUs, the taller the flame. Larger burners require more BTUs to have a large flame.
We label burners with suggested BTUs for a 16-20-inch campfire-like flame. A 24-inch burner needs 150,000 BTU for this. Lower BTUs yield a smaller flame, and higher BTUs a taller one.