Burn pits can be designed in various ways. These images illustrate a simple burn pit, with the horizontal burner anchored with a refractory block. The pit is contructed from an excavation, and uses angular gravel for its base material. No provisions have been made to control liquid seepage.
This image shows a burn pit burner of a different style - down for maintenance after four years operation. Note the base of the burn pit is a combination of refractory brick and concrete. The excavated bund is lined with gravel, except at the immediate penetration of the burner, where firebrick and refractry block is also used. The horizontal burner is mounted in a hrozizontal pipe sleeve, with the pilots on top of the burner
These two images show a different type of burn pit, with air assisted, vertical, burners arranged in a matrix. The burn pit is excavated, with gravel used for both base and berm walls.