1. Pressure magnitude

1.1 Thermodynamic approach

For an isotropic medium at thermodynamic equilibrium, energy E and entropy S are fundamental additive thermodynamic quantities. This means that the energy or entropy of the whole is equal to the sum of the energies or entropies of the various parts making up the macroscopic body.

Let's apply this principle to a fluid isolated in a volume V: for a given E, S depends only on V or, for a given S, E depends only on V and not on the shape of the body.

This results in the well-known total differential :

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Pressure magnitude

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page High pressure - From 50 MPa to 2 GPa

Instruments with deformable elements

Bibliography

(1) - ERARD (L.), REPOSEUR (P.) - Traçabilité et raccordement aux étalons nationaux. - AFNOR MTL-III-10-20 (2003).
(2) - BRIDGMAN (P.W.) - Proc. Am. Acad. Arts Sci., 47 (1911).
(3)...

Standards and norms

AFNOR/ISO

Valeur de la pesanteur terrestre - NF X02-011 - 1974
Exigences générales concernant la compétence des laboratoires d'étalonnages et d'essais - ISO/IEC 17025 - 2005
Measurement uncertainty – Part 3: Guide to the expression of uncertainty in measurement (GUM : 1995) - NF ISO/IEC Guide 98-3 - 2014

BNAE

Estimation des incertitudes sur les mesures de pression - RM Aéro...

Regulations

(Non-exhaustive list)

Décret n° 61-501 du 3 mai 1961 relatif aux unités de mesure et au contrôle des instruments de mesure (consolidated version as of June 13, 2020).

Directive 97/23/EC of the European Parliament and of the Council of May 29, 1997 on the approximation of the laws of the Member States concerning pressure equipment (OJ L 181 of July 9, 1997).

Directive...