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Interesting facts about Tietjen

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Noteworthy facts about Tietjen

Threshold time measurement - fast and uncomplicated

Dipl.-Ing. Tietjen GmbH carries out threshold time measurements and optimises existing compressed air brake systems, also with regard to Regulation EU 167/2013 (EU 2015/68).


Badde Baumaschinen from Dorsten leases and sells construction machinery and provides its own low-loaders for machine transport.



Badde urgently needed TÜV approval for a new trailer, for which, however, they lacked the threshold time measurement. For this, Badde had the trailer brought to Calle on their low-loader from Dorsten, over 200 km away.


The experts at Tietjen immediately carried out the threshold time measurement and issued the required document, as all values were in order.

Background: For new trailers or trailers purchased from abroad, the TÜV requires, among other things, a document on the threshold time measurement at the time of acceptance, which Tietjen carries out on site at the customer's or at its own premises. The threshold time measurement involves the response behaviour of the air brake on the trailer. The time required until the pneumatic control signal for braking comes in at the furthest wheel brake cylinder is measured. Tietjen uses the "Conformity Test Unit" (CTU) from WABCO for this. According to Regulation (EU) 2015/68, the threshold time may be max. 0.4 sec. Exceeding this value leads to delayed braking and delayed release of the brakes, thus posing a considerable safety risk.

It also sometimes happens that trailers do not reach the required value in the threshold time measurement. In these cases, Tietjen takes appropriate measures to improve the threshold time, e.g. by installing a relay valve or by adjusting the line cross-sections, which also has an influence on the response behaviour of the air brake system.

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