What is BS 718 - Density hydrometers about?
BS 718 specifies requirements for five basic series of glass hydrometers of constant mass which are graduated to indicate density (kg/m3 or g/ml) when used at 20 °C.
Each series comprises hydrometers that between them cover the interval of 600 kg/m3 to 2 000 kg/m3 (0.6 g/ml to 2.0 g/ml). The hydrometers are graduated appropriately for use in liquids of low, medium, or high surface tension.
Note: BS 718 does not cover hydrometers with a built-in thermometer (thermohydrometers).
Who is BS 718- Density hydrometers for?
BS 718 on the specification for density hydrometers is useful for:
- Density hydrometers manufacturers
- Quality control personnel
Why should you use BS 718- Density hydrometers?
BS 718 also specifies three sub-series of hydrometers which are graduated either to indicate density when used at 15 °C or to indicate density when used at 20 °C. They have smaller tolerances on scale error, are limited to the range 600 kg/m3 to 1 100 kg/m3 (0.6 g/ml to 1.1 g/ml) and are for use in liquids of low surface tension. A single hydrometer principally suitable for the measurement of the density of petroleum fuels is included.
BS 718 provides you with the series which governs the size of the hydrometer and the precision of readings and the range of hydrometer required. BS 718 provides you with surface tension category and special requirements, where unavoidable, in accordance with the particular circumstances. BS 718 helps you to manufacture high-quality density hydrometers.
What’s changed since the last update?
BS 718:1991 supersedes BS 718:1979 which is withdrawn. BS 718:1991 includes some technical changes with respect to BS 718:1979. These include:
- To align as nearly as practicable with ISO 387 and ISO 649 prepared by Technical Committee 48, Laboratory glassware and related apparatus, of the International Organization for Standardization (ISO)
- To restrict the scales of density to the exclusion of relative density (formerly termed specific gravity)
- As a step to the full utilization of basic SI units, introduce the option of scales marked in kg/m3 as an alternative to g/ml
