Calibration service

Calibration of your retroreflectometer – and DELTA as a DANAK accredited Testing and Calibration Laboratory

Properly calibration of your retroreflectometer is key in ensuring correct and repeatable measurements when testing pavement markings and road traffic signs for retroreflective performance.

In general

The retroreflectometer instruments LTL-M, LTL3000, LTL3500, LTL-XL, LTL-X Mark II, LTL2000-series, and RetroSign GR1, GR3 and GRX measure retroreflection characteristics of pavement markings and road traffic signs.

It is not sufficient to calibrate the instruments daily with the provided calibration reference to ensure its validity.

You also need to have the calibration reference itself calibrated or renewed regularly, especially if it is used frequently and / or used in harsh environments.

We recommend you having your your system calibration reference re-calibrated or renewed every 2-years –  or when the reference has become dirty beyond cleaning or has been damaged.

The Testing and Calibration Laboratory

DELTA is a DANAK accredited calibration laboratory and meets the ISO/IEC 17025:2018. DELTA offers re-calibration services of instruments. All re-calibrations or purchases of new calibration references are provided with a DANAK accredited calibration certificate at no additional costs.

An accredited calibration guarantees calibration in accordance with quality criteria stated in the DELTA’s Calibration Quality Manual and in line with international criteria for calibrations, ISO-ILAC-IAF, May 2017. DANAK certify DELTA for a 5-year period at a time with several control inspections during the certification period.


The Danish Accreditation Body, DANAK, is a member of the EA (The European Cooperation for Accreditation). It ensures international recognition of calibration certificates drawn up by DELTA’s Testing and Calibration Laboratory.

DELTA’s calibrations can be traced back to international calibration bodies like PTB (Physikalish-Technische Bundesanstalt, Germany) and NIST (National Institute of Standards and Technology, USA).

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