This International Standard specifies methods, procedures and equipment for the manual measurement of the temperature of bulk quantities of petroleum and petroleum products in storage tanks. The preferred method is to use a portable electronic thermometer as described in clause 7. Other methods included use permanently installed indicating thermometers of the spot-measurement type and temperature determination by sampling methods using cup-case thermometers, flushing-case thermometers, and thermometers within conventional tank samples taken in accordance with ISO 3170. This International Standard excludes averaging thermometers forming part of an automatic gauging system. These are described in ISO 4266.