DIN ISO 12858-1:2016-04

DIN ISO 12858-1 specifies the most important requirements of Invar levelling staffs used in geodesy and industry for precise measurement of heights in combination with either an optical-mechanical level equipped with a parallel plate micrometre, or a digital level of comparable precision. It is applicable to - classical staffs with graduation lines and numbering; - staffs used in digital levelling with code patterns. The measurement uncertainty of the height differences depends on a multitude of influencing factors of the whole measuring system including the levelling instruments. DIN ISO 12858-1 is not applicable to the detailed design and construction of Invar levelling staffs (such as materials, handles, fixing points for the struts, fixing of the Invar strip and of the circular level), which may be selected by the manufacturer as appropriate. DIN ISO 12858-1 replaces DIN 18717:1996-11. This standard differs from DIN 18717:1996-11 as follows: a) The overall structure of the standard is different, since it is an adoption of an ISO standard. The contents of ISO 12858-1 essentially correspond to DIN 18717, since the first version of the ISO standard of 1999 has been prepared on the basis of DIN 18717 with active German collaboration. Essential changes are listed in items b) to d): b) three different classes for the coefficient of thermal expansion have been introduced; c) three different classes for the graduation precision have been introduced; d) code staffs are specifically mentioned. The committee NA 005-03-04 AA "Geodätische Instrumente und Geräte (SpA zu ISO/TC 172/SC 6)" ("Geodetic instruments and devices (mirror committee to SpA to ISO/TC 172/SC 6)") at DIN is responsible for this standard.