The vat or container shall be large enough to hold at least 10% more than the largest load obtained for one cooking.
Shallow, flat vats shall be set in a firebox so that no more than one inch of the sides extends above the firebox.
Upright drums or metal barrels may extend above the firebox, provided the cooking operation has proved to be satisfactory and adequate.
A tight cover shall be provided and so designed that accumulated water of condensation will run back into the vat.
Fuel supply shall be adequate to maintain a continuous and controlled flame during the cooking period.
Cal. Code Regs. Tit. 3, § 794.4