Prophylactic fire protection in buildings with cast iron soil and waste water pipes

Cast iron with flake graphite as per EN 1561 corresponds to the building material class A1 as per German DIN 4102, which means it is incombustible.

As per the new European classification for the reaction to fire, Düker SML cast iron drainage pipe systems also correspond to A1 "non-combustible" as per EN 13501-1. This is the best existing classification. Further criteria such as "s" (smoke production) and "d" (flaming droplets) do not apply to products with A1 classification.

SML and the other variants of cast iron soil pipes are therefore the ideal partner for the prophylactic constructive fire protection.
For comparison: all plastic materials that are used for soil pipes are in class B1 (hardly inflammable) or even B2 (normally inflammable) as per German DIN 4102; or for example D - s2, d1 as per EN 13501-1. In case of a fire, these pipes can transfer fire through walls and ceilings, form toxic gas and, in some cases, form dangerous compounds together with the fire-fighting water. In order to reach the required fire protection, costly fire protection collars have to be used, which are to prevent the upwards transfer of fire.
Düker cast iron drainage pipe systems score in fire protection already without any additional measures: cast iron does not burn and does not emit any kind of gas in a fire. Up to 400°C, the mechanical characteristics of cast iron pipes remain unchanged (for some plastics this is only valid up to 70°C), the melting point is only reached at 1,300°C. The thermal expansion is also considerably lower than for plastic pipes.

Heat transfer as a residual risk in fire protection

When passing cast iron pipes through walls or ceilings with fire protection requirements, the possible heat transfer through the cast iron pipes must be considered as per the latest German regulations. This is particularly important where combustible pipes cross the same wall or ceiling next to the cast iron pipes, as these combustible pipes might ignite through the heat coming from the cast iron pipe. The German MLAR therefore introduced minimum distances in the year 2000. As these distances are often not realistic on site, common practice in Germany is to use pipe isolations that have been tested for zero-distance. For further information, please refer to the SML specifier's manual offered for download on the right-hand side.