Thermometer Storage and Fluid Separation
The science and development of non-mercury thermometers have made great improvements over the past few years. The blue spirit thermometers listed contain non-toxic isoamyl benzoate and dye. These thermometers can be stored horizontally; their separation rate is equal to or better than mercury thermometers. The red spirit thermometers that contain pentane or xylene and dye (-100° to 50°C and – 50° to 50°C) should be stored vertically to reduce the chances of separation.
Temperature Ranges and Limits
There are non-mercury thermometers with temperature and accuracy ranges equal to most mercury thermometers. An exception is on the high end of the temperature scale. Until recently 260° C was the typical limit for non-mercury thermometers. A new Brown-Spirit thermometer has a maximum range greater than 300° C but the accuracy limit can be ± 5°C at high temperatures. If scientific procedures cannot be performed with non-mercury thermometers, Teflon coated mercury thermometers should be used. The Teflon coating will help to reduce releases of mercury should a thermometer be broken.
Scale Divisions and Accuracy Limits
Non-mercury thermometers have scale divisions equal to mercury thermometers. Most range from 0.5° to 1° C. Accuracy limits for non-mercury thermometers below 150° C are also compatible with mercury thermometers; accuracy is typically ± 1° - 2° C. For thermometers that have a high range of 260° C, accuracy below 100° C is ± 1°-2° C for both mercury and non-mercury thermometers. Above 100° C mercury thermometers have an accuracy range of ± 1.5° C, while non-mercury have an accuracy limit of ± 3° C.
National Institute of Standards and Technology
All of the non-mercury thermometers listed meet NIST standards.
Cleanup and Disposal
The non-mercury thermometers are non-toxic and environmentally safe. The broken glass should be placed in a sharps container to prevent injury. The remaining liquid can be cleaned up with soap and water.