Ohio Rev. Code § 4104.13
Power boilers and high pressure, high temperature water boilers having internal continuous water treatment under the general supervision of a registered professional engineer having experience in the treatment of boiler water where said water treatment is for the purpose of controlling and limiting serious corrosion, and other deteriorating factors shall be thoroughly inspected internally and externally and under operating conditions at intervals of not more than two years and shall not be operated at pressures in excess of the safe working pressure stated in the certificate of operation mentioned in sections 4104.12 and 4104.15 of the Revised Code.
Process boilers having internal continuous water treatment under the general supervision of a registered professional engineer having experience in the treatment of boiler water where the water treatment is for the purpose of controlling and limiting serious corrosion and other deteriorating factors shall be thoroughly inspected internally and externally and under operating conditions at intervals of not more than five years and shall not be operated at pressures in excess of the safe working pressure stated in the certificate of operation mentioned in sections 4104.12 and 4104.15 of the Revised Code.
The owner or user of such boilers shall keep an accurate record which will show that samples of the boiler water have been taken at regular intervals not greater than forty-eight hours of operation, and the record shall show that the water conditions in the boilers meet the said controlling and limiting factors mentioned in this section, all in accordance with rules formulated by the board of building standards pursuant to section 4104.02 of the Revised Code. The owner or user of such boilers shall also keep a record of the date and actual time the boilers are out of service and the reason therefor, and all records mentioned in this section are to be made available by the owner or user of such boilers to the boiler inspector for his examination.
R.C. §4104.13