While performing the necessary work on private properties referred to above, the director of public utilities of duly authorized employees of the city shall observe all safety rules applicable to the premises established by the company, and the company shall be held harmless for injury or death to the city employees, and the city shall indemnify the company against loss or damage to its property by city employees and against liability claims and demands for personal injury damage asserted against the company and growing out of the gauging and sampling operation, except as such may be caused by negligence or failure of the company to maintain safe conditions. (Prior code § 9-313)