Emission Testing Devices | Calibration FIlter | Emission Testing Car Workshops


New EU Directive: Periodic Inspection of Emission Testing Devices Is Now Mandatory

Vehicle Emission Test I Source: © Hella Gutmann

Technical test centers (TP) and certified car workshops in Germany perform almost 24 million emission tests on cars, commercial vehicles and motorcycles every year. Growing environmental awareness and the introduction of special emission tests in 1985 and 1993 led to a continous further development of regulations.

Vehicle emissions have been in the spotlight for some time, not least because of the diesel emission scandal and constantly increasing demands on the exhaust gas behavior. Emission tests are performed directly on the exhaust tailpipe with special devices, such as the emission testing device produced by Hella Gutmann. A reliable exhaust testing device that provides accurate measurement results belongs to the basic equipment of any good car workshop and test center.

New regulations have recently been introduced to guarantee measuring accuracy and reliability of these devices.

How does this impact workshops and test centers?

In Germany, since January 1, 2019, stricter requirements apply with regards to the accuracy of exhaust emission devices and the annual calibration of those devices has become mandatory. Car dealers and emission test centers now have to provide proove of calibration of their exhaust emission equipment in order to stay permitted to calibrate. This is to ensure that the accuracy class remains unchanged over the application area of the exhaust emission device and that it is set up, connected and maintained in such a way that the accuracy of the measurement is guaranteed.


Emission testing devices have to provide exact measurement results I Source: © Hella Gutmann

The calibration is divided into an initial and a periodic calibration. Exhaust gas measuring devices that are put into operation for the first time must be calibrated according to the exhaust emission equipment calibration guideline. The regular calibration must then be carried out every 12 months, i.e. annually after the last calibration. It can be expected that prove of calibration becomes part of ISO 9001 audits for certified workshops. However, the requirement to calibrate also applies to non-certified workshops and test facilities.



Regular (Re-) calibration of exhaust emission devices in DIN EN ISO/IEC 17025 accredited laboratories to guarantee conformity with the reworked EU-directive. The corresponding calibration service must be included in the scope of the accreditation.

Field of Application

(Re-) calibration of exhaust emission devices in certified car workshops and technical testing centers.

Scope of Application

  • Emission Testing Devices
  • Calibration Filter
  • Turbidity Filter



  • Measurement Technology

  • UV/Vis Spectroscopy


  • UV/Vis-Spektroscopy

  • Online


  • Conformity with EU Directive 2014/45/EU
  • Save and Reliable Measurement Results

Not every laboratory has the permission to calibrate

The periodic calibration of the exhaust emission devices must be carried out by service providers who are accredited according to DIN EN ISO/IEC 17025. The turbidity filters used for the calibration of emission testing devices measure the opacity and must also be calibrated regularly by a metrological facility, such as a calibration laboratory accredited according to DIN EN ISO/IEC17025. The calibration is documented in a "calibration certificate" according to the requirements of DIN EN ISO/IEC 17025. The Hellma calibration laboratory has been accredited by the DAkkS according to DIN EN ISO/IEC 17025 and has been offering this service for several years. The accreditation is valid only for the scope listed in the annex of the accreditation certificate [D-K-18752-01-00].


Conformity to Regulations and Directives with the Right Partner

Turbidity Filter

Hellma calibrates in its  by the DAkkS accredited calibration laboratory according to DIN EN ISO / IEC 17025 turbidity filters of various brands and types. The accreditation is valid only for the scope listed in the annex of the accreditation certificate [D-K-18752-01-00].

Measuring devices differ, and so do the turbidity filters used. In the Hellma calibration laboratory filters of different designs can be calibrated in large quantities and in a short period of time. Filters sent in are inspected, in most cases cleaned and provided with a unique serial number so that the filter performance can be logged over a longer period of time. The subsequent measurement is documented with a calibration certificate, which also acts as evidence for test centers.

Get it all from one source

All services of the Hellma calibration laboratory at a glance

  • Inspection of the calibration filters send in by the customer
  • If the filter glass is not optically coated: cleaning of the calibration filters
  • Applying a unique serial number to guarantee clear labelling of the calibration filter
  • Measuring the optical density at a wavelength of 560 nm (measurements at other wavelengths are also possible if required)
  • Calculation of the opacity rate N (%).
  • Supply a DAkkS certificate according to DIN EN ISO/IEC 17025. The accreditation is valid only for the scope listed in the annex of the accreditation certificate [D-K-18752-01-00].



Hellma USA Inc.
120 Terminal Drive
11803 Plainview, NY
United States

Phone: +1 5169 3908 88


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