40 CFR §60.4390a

1. (a)You must maintain records of your information used to demonstrate compliance with this subpart as specified in § 60.7.
2. (b)An owner or operator of a stationary combustion turbine that uses the other fuels, part-load, or low temperature NOX standards in the compliance demonstration must maintain concurrent records of the hourly heat input, percent load, ambient temperature, and emissions data as applicable.
3. (c)An owner or operator of a stationary combustion turbine that uses the tuning NOX standard in the compliance demonstration must identify the hours on which the maintenance was performed and a description of the maintenance.
4. (d)An owner or operator of a stationary combustion turbine that demonstrates compliance using the output-based standard must maintain concurrent records of the total gross or net energy output and emissions data.
5. (e)An owner or operator of a stationary combustion turbine that demonstrates compliance using the water or steam to fuel ratio or a parameter continuous monitoring system must maintain continuous records of the appropriate parameters.
6. (f)An owner or operator of a stationary combustion turbine complying with the fuel-based SO2 standard must maintain records of the results of all fuel analyses or a current, valid purchase contract, tariff sheet, or transportation contract.