ASTM E563 Standard Practice for Preparation and Use of an Ice-Point Bath as a Reference Temperature

Get Certified ASTM E563

The accuracy of thermometry for industrial or laboratory use relies on a reliable fixed point of reference, and the ice point was one of the easiest and most available. AS639814 Certified testing by ASTM E563 is used to ensure that a laboratory properly prepares and maintains an ice-point bath for the calibration of resistance thermometers, thermocouples, and liquid-in-glass thermometers. Accredited laboratory practices support calibration facilities, instrument manufacturers, and industrial quality control programs in creating reliable reference temperatures. The Certified ASTM E563 practice ensures correct thermometry of all resistance, thermoelectric, and liquid-in-glass measurement systems. 

• Material type: Shaved ice and water mixture, saturated with air at standard atmospheric pressure.
• Purpose: Establishment of a fixed-point reference temperature for thermometer calibration.
• Properties evaluated: Reference temperature at the ice point, nominally 0 °C. 
• Testing Method: Preparation and maintenance of an ice-water bath, with thermometer immersion for calibration or reference use. 
• Result: A stable ice-point reference temperature suitable for resistance, thermoelectric, or liquid-in-glass thermometry.
• Test Limitations: This practice does not detail mechanical stirring methods for bath uniformity or thermostatically controlled ice-point approximation methods. 
• Environmental conditions: Atmospheric pressure, bath composition, and thermal isolation of the reference junction affect the accuracy of the ice-point reference.
• Applications: Resistance thermometer calibration, thermocouple reference-junction stabilization, liquid-in-glass thermometer recalibration, and industrial thermometry quality control.

What are the Uses of ASTM E563 Testing?

ASTM E563 testing helps laboratories in establishing a dependable ice-point reference temperature for calibrating multiple types of thermometers. Calibration technicians and instrument manufacturers then use this reference to verify thermometer accuracy against a known fixed point. This standard-

• Provides a readily available, natural fixed-point reference temperature for thermometry.
• Supports resistance thermometer calibration at the 0 °C ice point.
• Serves as the ordinary reference temperature for thermoelectric thermometry using thermocouples.
• Supports periodic recalibration of liquid-in-glass thermometers to detect glass strain relaxation.
• Relates ice-point reference values to the water triple point on ITS-90 for industrial applications.
• Supports calibration programs referenced by other ASTM standards that specify the ice point.

What Materials Can Be Tested Under ASTM E563? 

ASTM E563 applies to the preparation of an ice-point reference bath using shaved ice and water saturated with air at standard atmospheric pressure. This practice applies to the calibration of resistance thermometers, thermocouples used in thermoelectric thermometry, and liquid-in-glass thermometers. Before beginning bath preparation, an analyst verifies the intended thermometer type and the reference standard’s requirements, since resistance, thermoelectric, and liquid-in-glass thermometry each apply the ice-point reference somewhat differently.

Why is ASTM E563 Important? 

ASTM E563 provides a standardized method for preparing a fixed-point reference temperature that supports accurate thermometry throughout industrial and laboratory applications. The ice point is a common industrial reference point because it is relatively simple to realize and provides an established, readily available natural fixed-point reference temperature. Before 1960, the ice point served as a defining fixed point on practical temperature scales, and it remains the ordinary reference temperature in thermoelectric thermometry today. Periodic recalibration of a liquid-in-glass thermometer at the ice point also reveals the effect of gradual relaxation of residual mechanical strains in the glass, which can otherwise affect measurement accuracy over time.

ASTM E563 Testing Process and Data Collection

The preparation process consists of mixing finely shaved ice with water that is supersaturated with air at the standard atmospheric pressure in an appropriate insulated container. The thermometer, resistance element, or the thermocouple junction is placed in the bath so that good thermal contact is made and, in the case of the thermocouple, there is adequate electrical isolation from the bath and other thermocouples.  They allow the reading to stabilize, and they record the reference temperature indicated by the instrument under calibration. For resistance thermometers, technicians relate the measured resistance value to 0 °C with an uncertainty appropriate to the quality of the ice-point realization. Laboratories gather this reference data to support calibration records and periodic recalibration schedules for the thermometer types involved.

Common Challenges and Troubleshooting

The typical issues with the ASTM E563 practice are the non-homogeneous composition of the ice-water mixture, inadequate immersion depth of the thermometer, and poor isolation of thermocouple junctions thermally or electrically. These problems cause the realized reference temperature to deviate from the true ice point, introducing calibration errors. An insufficiently shaved or unevenly distributed ice-water mixture generates temperature gradients within the bath. Inadequate immersion depth allows radiation or conduction along the thermometer to perturb the reference-junction temperature. Poor electrical isolation between thermocouple junctions introduces measurement interference. A careful preparation of the bath, adequate immersion depth, and good thermal and electrical isolation reduce these problems. Experienced technicians achieve a reliable ice-point reference by following standard procedures and periodically verifying the bath composition.

• The laboratory documents the bath composition and preparation conditions used to realize the ice-point reference.
• Analysts record the thermometer type, resistance, thermoelectric, or liquid-in-glass, calibrated against the ice point.
• Results indicate the thermometer’s reading at 0 °C with an uncertainty appropriate to the quality of the ice-point realization.
• The laboratory relates the ice-point reference values to the water triple point on ITS-90 where required for industrial applications.
• For liquid-in-glass thermometers, the laboratory documents periodic recalibration results to check for gradual glass strain relaxation.
• Consistent bath preparation and proper thermometer immersion help laboratories deliver reliable, reproducible reference readings.
• The ice-point reference enables calibration records, which are referenced by other ASTM standards that specify this reference temperature.

Link to ASTM E563