Shoe-fitting fluoroscopes. (a) No fluoroscopic or x-ray equipment for fitting shoes shall be operated unless it is equipped with an automatic timer which will cut off each x-ray exposure at the end of a five-second interval.
(b) All establishments which use a shoe-fitting fluoroscope shall display at all times, in a location where all users can see it, a warning sign furnished by the state department of health.
(c) Exposure to the useful beam measured on the base of the foot opening in fluoroscopic shoe-fitting machines installed after September 1, 1955, shall not exceed 1.0 roentgen per five-second exposure.