The North Carolina State Fire Marshal shall be chief of the State Volunteer Fire Department; regular municipal fire chiefs shall be assistant chiefs; assistant chiefs shall be deputy chiefs; battalion chiefs, captains; lieutenants and privates shall hold the same position that they occupy in their municipal companies. When engaged in rendering assistance at the scene of any emergency, the ranking officer of the first department arriving at the scene of the emergency shall have complete charge of all operations until the arrival of a superior officer. All subordinate officers and men shall act under the direction of such ranking officer. Whenever present at the scene of an emergency, the chief shall have full and complete control and authority over operations of all members of the Department. (1939, c. 364, s. 3.)