FAQ Filter

Here you will find frequently asked questions from our customers

Does KRAHNEN GmbH offer a filter integrity test (DEHS test)?

Exam structure for the filter integrity test (DEHS)
Arrangement of filter integrity test (DEHS)

(Extract from SOP-0017857 4.2.5 / proof of the absence of leaks in built-in filter systems)
In some cases, continuous or cyclical control / monitoring of the filter elements is required. Thanks to the Krahnen modular system, an additional "police filter" with a DEHS test structure can be integrated into numerous vacuum cleaners.

This module is an important safety device, especially for stationary filter systems.

1. Basis of the examination

If the filters with class H 13 and H 14 are installed in order to maintain the room class or to protect the environment and people, the following filter test must be carried out.
The filter test is carried out on the last filter in the chain (in the air direction):


1 nozzle (type SERTO) for aerosol application. The nozzle must be placed in such a way that the aerosol is evenly distributed over the surface.

Raw air extraction

1 nozzle for raw air extraction. The nozzle must be placed in such a way that a representative measurement of the particles takes place on the filter inflow side.

Clean air extraction

The number of nozzles for the clean air extraction depends on the filter area. There is a measuring probe for each nozzle.