Fire protection measures are an important issue in drainpipe systems. The decision to use exclusively cast iron pipes for your drainage or a mixed installation is a crucial one. We explain the differences and the solutions that we offer.
Fire protection in drainage systems definitely needs to be taken into account during planning. However, misunderstandings often arise with regard to the different requirements for different drainage systems. The crucial difference is easy to explain: cast iron drainpipe systems are non-combustible, while mixed installations contain combustible pipe materials. This means that you generally do not need any additional fire protection measures for cast iron pipes, but you do for mixed installations: special fire protection solutions are essential.
A cast iron drainpipe installation poses no hazard in the event of a fire. Penetration sealing is not a big issue. In many cases, it is sufficient to seal the opening around the pipe with a non-combustible material. In doing so, you should ensure that you maintain certain minimum distances to neighbouring penetrations. The “facilitations” of the MLAR (German Model Conduit Systems Directive) provide all the necessary details on this: they are based on well-established construction types for which no special verifications or declarations of conformity are required. Another option is to rely on tested solutions. For cast iron pipe installations, penetration sealing systems from various manufacturers with an abP (German General Building Inspectorate Test Certificate) are available on the market. In this case, the distance to other penetration seals is generally five centimetres according to MLAR. For a select range of penetration seals, the test certificate even permits zero distance.
Pipes made of non-combustible materials, such as cast iron drainpipes, can be routed through F30 walls or ceilings without penetration seals. It is sufficient for the gap between the pipe and the wall to be filled with a non-combustible material to the thickness of the wall.
Individual cast iron pipes up to DN 150 can be routed through F60 and F90 walls or ceilings without penetration seals. In this instance, it is sufficient to fill the gap between the pipe and the wall with mineral wool or intumescent material. Mineral wool sheathing may also be used. Use of mortar, concrete or gypsum is permitted only in solid walls. However, this is usually not recommended for sound insulation reasons.
Cast iron conduit systems within escape routes may be exposed according to MLAR. In this case, it is also permitted for couplings and seals to be made of combustible materials (e.g. rubber). Combustible pipe coatings up to 0.5 mm thick are also permitted. All Dueker cast iron pipe systems are covered by this. Any insulation must be made of a non-combustible material. Metal anchors must be used for mounting. The same solutions may be used for penetrations through walls of escape routes as for F30 or F90 walls. The only exceptions to this are walls of essential stairwells, rooms between essential stairwells and exits to the outside.
If combustible pipe materials are incorporated in the drainpipe installation in addition to the non-combustible cast iron pipe, it is necessary to take additional measures for fire protection. In mixed installations, where the down pipe is made of cast iron and the connecting pipe is made of plastic, there are stricter test requirements that must be verified by means of an abZ (German General Building Inspectorate Approval) or an aBG (German General Building Approval). The facilitations of the MLAR must not be applied to fire protection penetration sealing in ceilings for typical mixed installations (down pipes made of cast iron, collector connecting pipes made entirely of plastic). Dueker offers a range of approved penetration seal solutions for mixed installations.
The Dueker fire protection branch is the all-in-one solution for mixed installations. It not only replaces the "Konfix" by a safe plug-in connection with a fixed stop - fire protection is also automatically included!
The push-in sleeve for the plastic pipe contains intumescent material that reliably seals the connection in the event of fire.
The partitioning system includes mineral wool (Rockwool RS 800), which is placed around the cast iron pipe and also serves as sound insulation. If installed behind a pre-wall, the mineral wool in ceiling thickness is sufficient. If there is no pre-wall, the mineral wool shell must be extended above the ceiling.
In the variant with pre-wall system, zero distance to supply lines made of steel, copper or multi-layer composite pipe with Rockwool penetration solutions is possible..
The detailed information can be found in the general type approval aBG Z-19.53-2589.
With the Dueker DBS fire protection system, a mixed installation can in principle be built in the same way as was common 20 years ago: no special fire protection elements, no special couplings, no intumescent mat, no awkward additional insulation. Instead, the penetration seal consists of a 20 mm thick mineral wool layer (Rockwool Klimarock), which is placed in the ceiling penetration around the cast iron pipe. The remaining gap is mortared. A pre-wall made of plasterboard that is at least 12.5 mm thick is fitted above and, if necessary, below the ceiling. The down pipe is made of cast iron up to DN 150; the plastic pipe must correspond to DN 50 to DN 100 and be connected directly to the cast iron branch using “Konfix”. The distance between the uppermost single branch with a transition to a connecting pipe (possibly plastic) and the lower edge of the ceiling above it must be at least 1950 mm. For down pipes of size DN 100 or smaller, any number of single branches may be arranged below this area, also as corner or double branches. All non-combustible pipeline systems according to the Viega German General Building Inspectorate Test Certificate P-2400/003/15-MPA BS with continuous non-combustible insulation are permitted as adjacent pipelines (supply). The first pipe must be at least 100 mm away from the cast iron pipe (measured from pipe to pipe).
The Dueker DBS system saves you time and money. There is no need for intumescent sleeves or special couplings, which means you avoid considerable material costs. No additional insulation is required, which saves you the cumbersome task of wrapping single branches. There is also no need to consider complicated installation conditions, which simplifies the construction site documentation. In general, the likelihood of errors during the installation of a Dueker DBS system is very low, which promises a high degree of acceptance reliability.
The Dueker BSV 90 fire protection coupling is an uncomplicated and space-saving solution for mixed installations. It is easy to install and does not require any additional thermal insulation. The Dueker BSV 90 (DN 80 – DN 150) can be installed in vertical cast iron drainpipes made by Dueker. It sits directly beneath the ceiling and projects 20–40 mm into the ceiling from below. A combustible sound insulation strip can be used in the ceiling. Above the ceiling, there are virtually no limits to the pipeline configuration. The typical application for the BSV 90 is in mixed installations, but it can also be used in pure cast iron pipe installations if required.
Whether you opt for cast iron pipes or a mixed installation, with Dueker you are guaranteed to find the right fire protection solution for your drainage system.