Third degree burns and at least 20% of the total skin area are affected

A thrid degree burn, and 20% of the total body surface
Rule of Nine
The depth of burn is classified into 4
degrees:
Superficial burn which affect the outer layer (epidermis) of skin only
Can be further divided into partial thickness or deep partial thickness burn.
Partial thickness
Affect both the epidermis and the superficial of the underlying skin (dermis)
Deep partial thickness
Affect both the epidermis and the deeper layers of the dermis
All the layers of the skin are affected
It affects the tissue below the skin which includes fat, bone or muscles.