Question about HANSA changeover valves ‘permanently technically tight’

In accordance with TRGS 722, HANSA change-over valves are ‘permanently technically tight’. It is an inherently tight component which ensures the flow of media in various directions by means of a spindle. The spindle is sealed to the outside by means of a stuffing box (see below). In addition, the cover of the spindle has a copper sealing ring.

As specified in the TRGS, however, it must be ensured that a suitable leak test is carried out on the system or the relevant section before commissioning, repairs and maintenance work.



Extract from TRGS 722 Section 4

4.5 Tightness of system components
4.5.1 General
(1) The formation of hazardous explosive mixtures inside and outside plant components can be prevented by the inside and outside plant components can be prevented or restricted by the tightness of the be prevented or restricted.
(2) A distinction is made here between
1. permanently technically leakproof plant components,
2. technically tight plant components and
3. system components with operational leakage of flammable hazardous substances.
(3) In the design of plant components for handling flammable gases, liquids and dusts, the following must be observed and dusts, the materials must be selected in such a way that they can withstand the expected mechanical, thermal and chemical stresses. Hazards due to abrasive stresses must be taken into account. Hazards due to reactions of the wall material with flammable hazardous substances must be ruled out.
(4) When selecting the materials, the corrosion behaviour must be

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