Liquid In Glass
Using NIST Traceable Standards

PTC Metrology® accredited by A2LA to ISO/IEC 17025 and ANSI/NCSL Z540-1. Certifications are NIST traceable and will include; as received and as returned data; a statement of uncertainty; laboratory conditions; and information on the primary standards. To assist you in choosing test points please refer to ASTM E-77 and NIST recommendations.

Calibration Procedure for Lig Thermometers

NIST traceable primary reference standards are used in accordance with PTC Metrology's ISO/IEC17025 quality standards. The unit under test (UUT) is inspected under polarized light utilizing a Polariscope for stress; the capillary is inspected under magnification to check for contaminates and discernible irregularities; and the UUT is held at 23°C for 72 hours. The UUT is compared with standard thermometers held by PTC Metrology. All measurements are traceable to NIST. The temperature scale used is the ITS-90 and all readings are in degrees Celsius unless noted. PTC Metrology is an A2LA accredited laboratory for temperature calibration.

Certifications will include as received and as returned data, a statement of uncertainty, laboratory conditions, and information on the primary standards.
Please note the minimum charge per instrument tested is $80.00

Model 243 Polariscope

The Polariscope is an essential tool for determining strain patterns developed during fabrication and manufacturing. It permits immediate determination of strains in most transparent materials. It is valuable in production or as a laboratory tool wherever glass is fabricated, welded or bent. Checking liquid in glass thermometers for stress is part of the calibration procedure.

As polarized light travels through strained glass or plastic, it undergoes a retardation proportional to the amount of stress. A Polariscope is an instrument which can be used to qualitatively view this retardation.