At all fires the Fire Chief shall adopt such measures as he may deem necessary for the protection of persons and property and the preservation of order, for which purpose he shall have all the powers of a police officer and may arrest or cause to be arrested any person acting in a riotous or disorderly manner. He may arrest any member or employee of the Fire Division who disobeys his orders and the police, while at a fire, shall, subject to the order of the Chief of Police, obey his orders. (1947 Code, Sec. 2-177.)