This part of ISO 16773 provides guidance on optimizing the collection of EIS data from high-impedance systems. High impedance in the context of intact coatings refers to systems with an impedance greater than 109 Ω⋅cm2. This does not preclude measurements on systems with lower impedance. This part of ISO 16773 deals with — instrumental set-up: requirements and pit-falls; — data validation: checking the measurement range and the accuracy of the data; — performing an EIS measurement: specimen considerations and instrumental parameters; — the experimental results: different methods of presenting EIS data. Following the recommendations should ensure the acquisition of EIS data that can be used to study the performance of the specimen. It does not give guidelines for the interpretation of the data.