This part of ISO 8655 specifies --metrological requirements, --maximum permissible errors, --requirements for marking and --information to be provided for users, for air-displacement (type A)and positive-displacement (type D)single-channel and multi-channel piston pipettes, complete with their selected tip(s)and any other essential,consumable parts,designed to deliver their specified nominal volume (Ex). NOTE General requirements and definitions of terms of piston-operated volumetric apparatus are given in ISO 8655-1. Conformity testing (type evaluation)of piston-operated volumetric apparatus is given in ISO 8655-6.Alternative test methods such as photometric and titrimetric methods will be the subject of a future Part 7 to ISO 8655.For all other tests (e.g.quality assurance by the supplier,analytical and measuring equipment quality assurance by the user)see ISO 8655-6 or alternative test methods. For safety requirements of electrically powered piston pipettes,see IEC 61010-1.