(a) Before existing systems installed prior to July 1, 1952, may be approved as complying with the requirements of the Part, they shall be examined and tested by the department. Such systems shall comply with the following requirements:

1. (1) They shall be in operative condition, shall be free from mechanical injury, structural defects, and obstructions, and shall present no physical hazard.
2. (2) They shall have a water supply of adequate pressure and capacity, and shall function automatically at the operating temperatures set forth in this Part for new installations.
3. (3) They shall, upon actuation by heat produced by fire, automatically distribute water upon the fire in sufficient quantities either to extinguish it entirely or confine it without spread.