ISO 17025 is applicable to all testing and calibration laboratories.
For flow meter calibration, this will include specifying the specific type of fluids and range in the scope – e.g. Water, Air, Liquid Carbon Dioxide (CO2). For storage tank calibration, you would include the service and type of tanks that are being measured (volume or dimensions), plus calibration technique and procedure must be specified – e.g. volume and density of Industrial volumetric equipment and bulk storage tanks using Scanning length measurement.
Depending on the country and industrial sector, there may be additional requirements. For example, the American Petroleum Institute.