While performing the necessary work on private properties referred to in § 82-234 of this chapter, the Superintendent or duly authorized city employees shall observe all safety rules applicable to the premises established by the company. The company shall not be held liable for injury or death to the city employees. 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 or property 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.