Accredited calibration services:

From -196^oC to 1000^oC ASTM thermometers, digital thermometers, PRTs, thermocouples, thermistors

Specific Gravity hydrometers. API hydrometers, Baume hydrometers,
Kg/M3 (density) hydrometers, Brix hydrometers, Proof hydrometers

ASTM Class 1 and OIML E-2 and lesser specification stainless steel and brass laboratory weights. New calibrated weights and re-calibration of weights you currently have.

Thermo-hygrometers, chart recorders, humidity sensors, data-loggers

Burets, pipets, volumetric flasks, graduated cylinders, volumetric glassware

Testing and certification that an instrument complies with specified accuracy requirements...

NIST TRACEABLE TEMPERATURE CALIBRATION SERVICES

CALIBRATION OF A LIQUID-IN-GLASS THERMOMETER . . .
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Pre-calibration inspection
Every manufactured product has the potential for defects and thermometers are no exception. We look first for obvi o us flaws – mistakes in numbers, bad lines, cracks or minor defects. Here we are inspecting the thermometer under a polarized light source, looking for evidence of strain or damage to the glass, either residual from manufacturing or as a result of thermal shock in use.

Inspection of the capillary
The mercury or spirit filling is drawn down to the bulb by the application of suitable cooling, and the entire capillary is visually inspected under a 20x microscope to be certain that no liquid separations, moisture, foreign matter, or undue capillary irregularities are present.

Information on rejoining mercury separations

PRE-Testing CONDITIONING
Prior to calibration a liquid-in-glass thermometer must be 'at rest', essentially out-of-service and at room temperature, for a period of 72 hours (this is an ASTM E-77 and NIST requirement). This permits the bulb (the most sensitive part of a thermometer and the part most subject to changes from thermal stress) to return to a state of equilibrium.

Test temperatures ASTM specifications set forth the series of temperatures (test points) at which a particular ASTM thermometer must be calibrated in order to comply with ASTM requirements. For non-ASTM thermometers, there are nonetheless ASTM and NIST guidelines for the selection of test temperatures. Choosing test points for non-ASTM thermometers

After the thermometer has been permitted to 'rest', it is first tested in an ice point bath (crushed ice made from distilled water) at 0^oC or (32^oF) and thereafter at the chosen series of temperatures, in ascending order.

COMPARISON CALIBRATION
Our 17025 Procedure 01 is based on ASTM E-77 and incorporates the best practices that our 31+ years of experience have taught us – as an example, all calibrations require the use of a check standard (a second reference thermometer). The standard and the check standard must be in agreement within +/- 0.01^oC or the calibration process must stop and the supervisor is consulted.

Indications of the clients' thermometer are read 3 times under 10X magnification, resolved to 1/10 of the smallest scale division, and carefully noted on the work card both in numerical and graphical format..

Our comparator baths are state-of -the-art baths from Hart Scientific and PolyScience, all digital microprocessor controlled.

Bath temperatures are set and monitored with secondary standard PRTs read on Hart Scientific 1560 'Black Stack' readouts; ASTM precision series thermometers (ASTM 62C through 70C) are used as check standards.

The secondary standard PRTs and the ASTM check standards are calibrated by direct comparison against our NIST calibrated primary reference SPRTs (see below).

Formally trained, experienced calibration personnel are essential to the precision of the calibration. All ICL's technicians have extensive NIST, Hart Scientific and other relevant training, and years of experience. Training and qualification records (NIST and other certificates) for our calibration personnel are furnished on request. Contact J. Jeff Kelly, Technical Director

NIST Reference Standards

The best calibrations begin with the best reference standards. We use NIST CALIBRATED SPRTs manufactured by Hart Scientific. (SPRT is an acronym for Standard Platinum Resistance Thermometer - the defining instrument of the ITS-90 temperature scale.)

Our SPRTs are calibrated by NIST.

If you want a shorter traceability chain than ICL provides, you'll have to go to NIST directly.

At right: calibrating a check standard by comparison with a NIST calibrated SPRT thermometer connected to our Hart Scientific 1575 'Super Thermometer' readout (thermometry bridge).

Accuracy of the Hart 1575 is 4 ppm or approximately 0.001�C

CALIBRATION REPORT DOCUMENT

You need to be concerned about the Report of Test that your calibration supplier gives you: not only must the information be accurate, but it must be easy to understand, complete, and meet all program requirements, because your auditor is going to examine it in detail and either approve it or disapprove it - and if it is disapproved you've got a deficiency to resolve.

ISO/IEC 17025 specifies the elements which must be present on a Report of Test for it to be valid. ICL’s reports comply with all ISO/IEC 17025 requirements, and go beyond, containing information that you, the client, have asked for, including:

ASTM or manufacturer's tolerances

"As found" and "as left" readings

Identification of all primary, transfer and check standards and equipment (comparators) used in the calibration.

Uncertainties of our NIST reference standards

All 2 page (1 sheet, front and back) test reports are laminated in heavy plastic for durability in the demanding laboratory environment. Multi-page reports are furnished in a durable binder.

Sample Thermometer Calibration Report

Tagging the instrument for identification
A durable calibration tag is affixed to the thermometer, indicating the date of most recent calibration and the 'next due' date.

Record retention
All physical records, raw data, and worksheets pertaining to your calibration, including copies of the calibration report, are retained for at least five years. Database records of report data are maintained on-line, instantly accessible for at least two years. Replacement Test Reports can be furnished quickly and inexpensively should your original become lost.

notification when next calibration is due

When calibrated, your instrument is entered into our database. We will notify you by fax when your instrument is due for recalibration. (One less thing for you to have to keep track of.).

Download recalibration form and address label to send in your instrument for calibration