On-Site and Mobile Calibrations

Dickson TP 125 data logger

When organizations look to have calibrations performed on their equipment, on-site calibrations are one option that they can choose that provides a number of benefits to both reducing costs and improving productivity.

On-site calibrations are defined as calibrations that are performed outside of the main calibration laboratory’s facilities. Those calibrations are usually at a customer’s manufacturing or service facilities but can also be at warehouses or at remote field service locations.

On-site calibrations are very useful for organizations that have a large number of items to be calibrated, have items that cannot be moved, such as ovens, environmental chambers and floor scales or have items that are very sensitive, such as analytical balances. On-site calibrations are appropriate in many situations however, some items do not lend themselves to be calibrated on-site depending on the equipment accuracies involved or the environmental conditions that are present in the on-site environment.

On-Site Calibration Benefits

Some of the main advantages of having calibrations performed on-site include:

On-Site Calibration Process

The process during the on-site calibration is fairly simple. Before the technicians arrive, arrangements are made to gather all of the equipment to be calibrated and place them in an area where the calibration technicians can freely work on them. The area should be in a clean location away from the main operations in the facility. It should have adequate power available for the calibration standards and stable temperature conditions. For equipment that cannot be moved, the technicians will perform the calibrations at those locations.

When the calibration technicians arrive at the facility, they will review the calibrations to be performed and discuss any special requirements for the calibrations or documentation that is needed.

During the calibration, the measurement data is usually kept within a software-based program that can be downloaded directly into the main laboratory’s system. If an item is found to be out-of-tolerance, the technicians can show the appropriate personnel the measurement data so that they can determine how that condition may have affected their operation. After the calibrations are complete, the technicians will print out all of the required calibration certificates and measurement data that were agreed upon with the customer.

Measurement Uncertainty Influences

One of the biggest disadvantages in performing calibrations on-site is in the adjustments required to the measurement uncertainty values reported by the laboratory. When calibration laboratories publish their measurement uncertainty values on their Scope of Accreditation, they use the environmental conditions that are controlled within the laboratory and they use the best equipment standards available for the calibration parameter. For on-site calibrations, the environment rarely has the same environmental characteristics and many of the best standards in a laboratory are not designed to be mobile or used in widely fluctuating environmental conditions.

The way laboratories account for this is to expand the measurement uncertainty value to account for those variations. They either monitor the environmental conditions at the site during the calibration and recalculate the measurement uncertainty values to be reported on the calibration certificate or they use a ‘worst-case’ value that will encompass all of the known measurement uncertainty influences present at a location outside of the main laboratory. In either case, the organization purchasing the calibration services needs to be aware of the situation and take those considerations into account when determining if the on-site calibration will meet their needs.

Mobile Calibration Labs

One way of offsetting the measurement uncertainty issue is with the use of a mobile calibration laboratory. A mobile calibration laboratory is a laboratory that is built within a mobile vehicle or trailer. Technicians can control the mobile environment within a nominal range for the types of calibrations being performed. This helps to recreate the conditions that exist within the main laboratory and allow the calibration technicians to use the same equipment standards, use the same procedures and perform the same types of calibrations as they would within the main laboratory.


To ensure that organizations get the services they need it is best to ask questions with the on-site calibration technicians and make them aware of any special requirements that need to be addressed. Communication is vitally important to ensure that the proper testing is being performed and that the documentation fulfills all of the audit or regulatory requirements within the organization.

Do you need on-site calibration services? e2b Calibration is capable of performing a wide variety of calibration services at your location with our highly trained technicians. If you are interested in learning how we can serve your calibration needs or answer any questions you have, contact us at e2b calibration.


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