Berry, J; Davidson, S; Brown, S (2007) The development of artefacts for the gravimetric measurement of the density of moist air. NPL Report. ENG 1

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Abstract

High accuracy air density measurements are needed in calibrations of OIML E1 and E2 class mass standards, becoming more vital when calibrating a secondary stainless steel mass standard from a primary platinum-iridium (Pt-Ir) standard due to the large difference in volume between them. Current state of the art air density measurements using the conventional CIPM-81/91 method can measure air density to about 1 part in 10 to the power of 4 (k = 1). However, gravimetric air density artefacts offer the opportunity to measure moist air density to about 1 part in 10 to the power of 5 (k = 1), which would reduce the uncertainty on stainless steel – Pt-Ir calibrations by up to 50%. The moist air density measurements made using gravimetric artefacts presented in this report have demonstrated excellent agreement with the CIPM-81/91 method and offer an improved uncertainty of 1.1 parts in 10 to the power of 5 (k = 1).

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	ENG 1
Keywords:	air density, mass, weight
Subjects:	Engineering Measurements Engineering Measurements > Mass, Force, Pressure
Last Modified:	02 Feb 2018 13:15
URI:	https://eprintspublications.npl.co.uk/id/eprint/3868