Ring ropes shall be at least four in number, not less than one inch in diameter; the lower rope 18 inches above the ring floor, the second rope 30 inches above the floor, the third rope 42 inches above the floor, and the fourth rope 54 inches above the ring floor. The lower rope shall have applied around it a padding of a thickness of not less than one-half inch and of a type and construction to be approved by the commission.