This standard specifies the photometric and titrimetric determination of errors of measurement of piston-operated volumetric apparatus. The tests are applicable to complete systems comprising the basic apparatus and all parts selected for use with the apparatus, disposable or reusable, involved in the measurement by delivery process. These non-gravimetric test methods can be applied . as aids to quality assurance by the supplier, . as routine quality assurance and routine calibrations by the user, and . as routine and post-repair testing. The methods described in this part of ISO 8655 are not applicable as alternatives to the gravimetric reference test methods specified in ISO 8655-6, which gives the only method suitable as a basis for supplier's declarations or independent certification of conformity. NOTE 1 Metrological requirements for piston-operated volumetric apparatus, especially maximum permissible errors, are specified in ISO 8655-2 to ISO 8655-5. NOTE 2 For conformity tests or type tests for declaration and certification of conformity, see the gravimetric reference test methods in ISO 8655-6.