1.1 This Recommendation specifies the metrological and technical requirements for general-purpose, liquidin- glass thermometers(1) intended for laboratory use as reference or working temperature standards. The thermometers are graduated in degrees Celsius and divided into six accuracy classes (see 5.2.2) that apply to thermometers operating within the temperature range of – 200 °C to + 500 °C. 1.2 This Recommendation covers solid-stem and enclosed-scale thermometers. In addition, such thermometers may be complete immersion, total immersion, or partial immersion thermometers. The performance requirements for thermometers containing mercury and organic liquids as thermometric liquids are specifically covered in this Recommendation. Requirements for thermometers containing other liquids such as gallium and mercury-thallium could be developed by applying the same principles. 1.3 A test procedure is given to determine if the thermometers meet each specified requirement under specified laboratory conditions. Such procedure includes visual inspection and tests on permanency of pigment, bulb stability, and determination of errors. 1.4 This Recommendation does not apply to maximum registering thermometers, such as those used to measure body temperature.