GOST 28947-91 PDF

Full title and description

GOST 28947-91 — "Ареометры стеклянные. Стандартное значение коэффициента объёмного термического расширения (для использования при подготовке поправочных таблиц для жидкостей)". Defines a conventional value for the thermal cubic (volume) expansion coefficient of glass hydrometers for use when preparing measurement/correction tables for liquids; includes guidance for applying tables to hydrometers whose expansion coefficient differs from the conventional value.

Abstract

This standard specifies a conventional value for the thermal cubic expansion coefficient of glass hydrometers (used when preparing measurement and correction tables for liquids), gives the recommended standard temperatures (e.g., 20 °C as preferred, with 15 °C or 27 °C as alternatives), provides correction formulae and tables to adjust hydrometer readings when the actual thermal expansion coefficient differs from the conventional value, and aligns with the corresponding ISO document. The conventional value adopted is 0.000025 per °C.

General information

• Status: Active / in force (действует).
• Publication date: 1991 (approved 29 March 1991; introduced into force 1 January 1993).
• Publisher: Izdatel'stvo standartov (Publishing House of Standards), Moscow; prepared by SKTB SP (Klin).
• ICS / categories: 17.060 — Measurement of volume, mass, density, viscosity.
• Edition / version: Original GOST edition, 1991 (ГОСТ 28947-91).
• Number of pages: 4 (concise technical standard with tables).

Scope

The standard applies to glass hydrometers used to determine liquid densities and specifies the conventional value of the hydrometer thermal cubic (volume) expansion coefficient to be used when preparing measurement (correction) tables for liquids. It also describes how to correct hydrometer readings and tables when a hydrometer’s actual expansion coefficient differs from the conventional value. The standard is intended to ensure consistency of density measurements and correction-table construction across laboratories and industry users.

Key topics and requirements

• Conventional thermal cubic expansion coefficient for glass hydrometers: 0.000025 per °C (used as the reference coefficient when preparing correction/measurement tables).
• Preferred standard temperature for hydrometers: 20 °C (other recommended standard temperatures include 15 °C and 27 °C) — specified for preparation and use of tables.
• Formulae and tabulated correction factors to adjust readings when a hydrometer’s actual volume expansion coefficient differs from the conventional value; instructions for applying corrections before using tables prepared with the conventional coefficient.
• Provision of correction tables for common density ranges (tables in the standard give corrections in 0.001 relative density increments and in °F for some tables).
• Compatibility and correspondence with ISO 1768 (ISO 1768 / ISO R 1768 family — Glass hydrometers: conventional value for the thermal cubic expansion coefficient).

Typical use and users

Metrology institutes, calibration laboratories, petroleum and chemical laboratories, manufacturers and inspectors of hydrometers, quality-control and testing laboratories that use hydrometers for density/relative-density measurements, and standards bodies preparing or using density correction tables. The standard is used when preparing measurement tables, calibrating hydrometers, or adjusting readings from hydrometers whose expansion behaviour differs from the conventional value.

Related standards

ISO 1768 (Glass hydrometers — Conventional value for the thermal cubic expansion coefficient) and earlier ISO Recommendation R 1768; other GOST/ISO documents covering hydrometer construction, calibration and density measurement methods may be used alongside GOST 28947-91 when performing full metrological procedures.

Keywords

GOST 28947-91, glass hydrometers, hydrometer thermal expansion, thermal cubic expansion coefficient, correction tables, density measurement, metrology, ISO 1768, volume expansion, calibration.

FAQ

Q: What is this standard?

A: GOST 28947-91 is a national standard that specifies a conventional value for the thermal cubic (volume) expansion coefficient of glass hydrometers for use when preparing measurement and correction tables for liquids, and it describes how to correct readings and tables when hydrometers have different expansion coefficients.

Q: What does it cover?

A: It covers the conventional numeric value for the coefficient (0.000025 per °C), recommended standard temperatures (20 °C preferred; 15 °C or 27 °C may be used), correction formulae and tables for adjusting hydrometer readings, and guidance for preparing and using measurement tables for liquids.

Q: Who typically uses it?

A: Calibration and testing laboratories, metrology institutes, hydrometer manufacturers, petroleum and chemical industry labs, and any organization preparing or using hydrometer-based density/correction tables. It is a reference for practitioners needing consistent correction factors for glass hydrometers.

Q: Is it current or superseded?

A: According to standard catalogs and libraries, GOST 28947-91 is listed as active / in force (introduced 1 January 1993) and corresponds to the ISO document on the same subject; users should check national/regional standards repositories for the latest status or any subsequent revisions.

Q: Is it part of a series?

A: It is a stand-alone GOST addressing the conventional expansion coefficient for glass hydrometers but is normally used together with other GOSTs/ISO standards dealing with hydrometer construction, calibration and density measurement methods (for example, ISO/GOST documents on hydrometer specifications and density tables).

Q: What are the key keywords?

A: Glass hydrometers; thermal cubic expansion coefficient; 0.000025 per °C; correction tables; density measurement; calibration; ISO 1768; metrology.