ISO 7976-1 : Tolerances for building - Methods of measurement of buildings and building products - Part 1 : Methods and instruments.

ISO 7976-1:1989 specifies standardized methods and instruments for measuring the dimensions, geometry, and tolerances of buildings and construction products, both in manufacturing facilities and on construction sites. It describes procedures for verifying length, thickness, squareness, straightness, flatness, warping, verticality, levelness, the positioning of elements, joints, and bearing surfaces. The standard also defines the measurement conditions (temperature, humidity, and object positioning), the appropriate measuring instruments (measuring tapes, theodolites, levels, laser devices, calipers, plumb lines, etc.), and the required measurement accuracy according to the tolerances being assessed. In addition, it provides accuracy tables, recommendations for minimizing measurement errors, and an annex explaining the corrections to be applied to measuring tapes to account for temperature, sag, and inclination.