scope:

This Standard specifies requirements for five basic series (L20, L50, M50, M100 and S50) of glass hydrometers of constant mass which are graduated to indicate density (kg/m³ or g/cm³ ) at 20°C or 15 °C.

Each series comprises hydrometers which between them cover the interval 600 kg/m³ to 2 000 kg/m³ (0.600 g/cm³ to 2.000 g/cm³ ).

The hydrometers are graduated appropriately for use in liquids of low, medium or high surface tension.

It also specifies three sub-series (L50SP, M50SP and S50SP) of hydrometers which are graduated to indicate density at either 20°C or 15 °C. These hydrometers are limited to the range 600 kg/m³ to 1 100 kg/m³ (0.600-g/emS-to 1.100 g/cm³ ) and are for use in liquids of low surface tension.

The density hydrometers shall follow the principles of construction and adjustment specified in ISO 387. This Standard does not cover hydrometers with a built-in thermometer.

A table of standard categories of surface tension is given in Annex A. A table of recommended stem diameters is given, for guidance in manufacture, in Annex B.

Examples of form of density hydrometer are shown in figure 1.

Density hydrometers used for transactions or certifications are given in Annex JA and Annex JB.

NOTE: The International Standard corresponding to this Standard and the symbol of degree of correspondence are as follows.

ISO 649-1: 1981 Laboratory glassware-Density hydrometers for general purposes-Part 1: Specification (MOD)

In addition, symbols which denote the degree of correspondence in the contents between the relevant International Standard and JIS are IDT (identical), MOD (modified), and NEQ (not equivalent) according to ISO/IEC Guide 21-1.