229 Neb. Admin. Code, ch. 24, § 013
Owners or users of units installed in heating systems that use glycol in the system shall maintain records available for review by the inspector that show the type of glycol used, the concentration of glycol in the system, dates the system was tested and test results, the minimum and maximum allowable concentration allowed, the pH range of the solution and the dates and amounts of any addition of glycol. Should the system require cleansing after removing old or damaged anti-freeze, owners or users shall flush the system with a heated 1-2% solution of trisodium phosphate for 2 to 4 hours, or as the glycol manufacturer recommends, and then drain and rinse the system thoroughly. Any boiler with inspection openings used in a glycol system that has been flushed shall have an internal inspection performed by a state inspector or a special inspector before the system is refilled.
229 Neb. Admin. Code, ch. 24, § 013