Düker GmbH

Cast iron benefit: Non-combustibility

As yet, national "reaction to fire" are still being used in many European countries. However, in the long run people will have to get used to "Euroclasses", the reaction to fire as per EN 13501-1.

Düker SML has been classified A1 "non-combustible" as per EN 13501-1. This is the best existing classification.

For the classifications A2 up to D, additional values must be stated for "s" (smoke generation) and "d" (flaming droplets). Therefore the classification for   Düker MLK-protec, TML and MLB is A2, s1, d0 - the second best existing classification of a total of 40 classes.

The following table gives the approximate correspondence between the new European classification and some older national classifications:



Reaction to fire
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Cast iron benefit: no flashover

The classifications contained in EN 13501-1 are based on the typical phases of a fire in a room. A small-scale fire will at first spread quite slowly. In the process, the heat radiation will increase continuously. When the heat release surpasses a certain limit, all neighbouring combustible materials will ignite in a sudden burst - the so-called flashover. After the flashover, the odds of survival in the room decline rapidly.

As described in annex A of EN 13501-1, the classifications of reaction to fire indicate if and how fast a construction product provokes a flashover:



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Cast iron benefit: no flaming droplets

Flaming droplets, i. e. the falling down of burning material, does not occur on Düker drainage pipe systems, neither in tests nor in practice.

For plastic pipe systems, depending on the material used, flaming droplets need always be taken into account. Even "reaction to fire" classifications with the "d0" parameter are misleading in this respect. It must be considered that during the fire test that is carried out to determine the "d" parameter (SBI test as per EN 13823 and single-flame source test as per ISO 11925-2), flaming droplets are recorded only in a very limited way and over very short periods, partly only for 35 seconds.

Flaming droplets are prone to falling through fire-rated floors, even if a fire collar is installed below the floor, and to start new fires both in the plastic pipe and on the floor of the fire compartment below the compartment where the fire started. The fire collar below the floor of the fire area will not close in time, as it requires temperatures of 140°C or more to close, which will not occur below the fire-rated floor.


The valid version of EN 1366-3, which defines the fire tests for fire resistance approvals, does not stipulate any test for this phenomenon. Therefore, valid approvals do not prove if flaming droplets can occur or not.






Cast Iron Benefit: little smoke generation

If installed with couplings whose rubber gaskets are completely covered by stainless steel collars (e.g. Dükorapid®), the pipe system remains closed in case of a fire. Any smoke generated by heat effects on the inner coating remains within the pipeline and ist then evacuated through the ventilation openings over the roof.




SML Specifier's Manual (pdf, 5.185 KB)

with detailed information on reaction to fire of Düker SML.

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