To perform a thorough investigation, you must first understand how burns are classified.
Different grades of burns are assigned by how "deep" the burn goes into the skin. The names given to burns have changed over the recent decades, but you should know the names and characteristics of each type of burn.
An injury to the top layer of skin is called a superficial burn (formerly known as a first-degree burn); it heals within five to seven days. When the second layer of skin is damaged it is known as a partial burn (formerly second degree). When the damage goes through to subcutaneous tissue and fat, it is known as a full thickness burn (formerly third degree) and requires skin grafts.
Several factors affect the severity of an injury. The injury location and the victim's age determine the thickness of the skin. Water and oil content, the amount of subcutaneous fat, and the number of blood vessels vary from one location in the body to another. A child's skin is thicker on the palms of the hands, soles of the feet, and the back. Skin is thinner on the front of the trunk, the inner arms and thighs, and the bottom of the forearms.
Only a trained medical professional can make a complete determination as to the severity of a burn. Develop a good rapport with responding medical personnel to help assess the types of burns that have been inflicted.