WHAT ARE FIELD CALIBRATIONS?

Calibration laboratories perform calibrations in accordance with their accreditation, at the laboratory site or at customer/client sites. The latter is referred to as field calibration or field calibration .

“Calibration is defined by the International Dictionary of Metrology as “the operation of establishing the relationship between the value of a measurand with the associated uncertainty of a known standard and the indication of the value with the associated uncertainty of the instrument”.

In accordance with its accreditation, the ELPRO Calibration Laboratory performs temperature and relative humidity calibrations, also in the field, with customers or clients as defined by the 17025 standard.

The decision on the place of performance is an agreement between the customer and the laboratory, but the basic rule applies first and foremost: “If the instrument is portable, the calibration shall be carried out under controlled ambient conditions in the laboratory”. However, if the user’s requirement and need is such that calibration must be carried out on site; e.g. very difficult dismantling, high potential for damage, etc., the laboratory shall consider its capabilities and prepare for field work. Depending on the preparation and the generators used at the comparison site, this can be a simple or a very complex equipment move, and the cost and complexity of the calibration itself depends on this.

Differences between calibration in the laboratory and calibration in the field:

Benefits of the ELPRO Calibration Laboratory:

• very wide temperature measurement range from -200 to 1820 °C
• flexibility of locations: partly in the laboratory, partly in the field (cost savings, economy, flexibility, speed)

Benefits of having an activity in the house:

• 30 years of experience with ELPRO Lepenik manufacturing temperature sensors and selling measurement and control equipment
• expert advice on the purchase of measuring equipment
• repairs of plant, machinery, automation …

An example of field calibration:

• Calibration of the heating chamber, measurement of the homogeneity of the temperature field of the chamber
• Location: slovenian metal processing company

Based on a preliminary site inspection and the customer’s requirements, we prepare a calibration order. In the laboratory, we prepare and recalibrate the equipment (pre-field calibration) and check the instruments.

The homogeneity of a rectangular heating chamber of dimensions approximately 2 m × 4 m × 2 m (H × W × D) is measured at an operating temperature of about 180 °C. In accordance with the calibration procedure for chamber validation, the temperature is measured at 9 points in the chamber. Data logging is automated, with measurement times ranging from a few hours to a few days, depending on the process. Use specially prepared and calibrated temperature sensors, manufactured by ELPRO Lepenik. The adaptation of the sensors is necessary due to the difficult accessibility of the measuring points. The recorded values are transferred to the laboratory software where they are edited in the Chamber Validation Report according to EN60068-3-5, EN60068-3-6, EN60068-3-7, EN360068-3-11, AMS 2750, CQI 9 … The equipment used to perform the calibration is recalibrated and checked to exclude any deterioration of the calibration (field calibration). The results and the certificate/report are forwarded to the client.

The purpose of calibration is to determine the actual situation, so the most important thing is to have confidence in the result. Based on the result, the contracting authority confirms the adequacy of the situation or takes the necessary measures. Calibrations have great value when used as intended.

EXPERT ARTICLE: What are field calibrations?

Author Aleksandra Lepenik
January 2022

WRITE TO US or CALL US. Our experts

they will offer you the best solution in line with

your wishes, requirements, scope of application

or an app!