Problematic: building type E for lift building

The German Federal Ministry of Building and Federal Ministry of Justice laid down the key points for building type E at the end of 2025. These could prove to be problematic from a lift building point of view, particularly when it comes to sound insulation.

BY ULRICH NEES

First off: the “E” stands for simple and experimental building. The aim is to make it simpler for those involved in construction projects to diverge from legally non-mandatory standards, such as purely comfort and equipment standards. Building contract law is to be amended for this purpose. A corresponding law is planned for the end of 2026.

Building type E will bring a series of challenges in its train for lifts. These will have to be mastered in agreement between client and contractor, making use of the technical and legal options available.

Among other things, the federal ministries list the following criteria among the key points for building type E:

dispensing with expensive features such as basements, underground garages, parking spaces and lifts,

• up to four upper floors without lifts but with preliminary equipment,
• reduced component thickness for acoustic decoupling of lifts,
• undershooting the building code noise insulation standard,
• undershooting the footfall noise protection.

In addition, the “Building type E agreement” is intended to facilitate diverging from generally acknowledged technical rules without this counting directly as a defect. However, this is in conflict with health protection called for by the verdict of 14 June 2007 of the Federal Supreme Court with regard to sound insulation. This specified that the noise level in rooms requiring protection, such as bed- and living rooms, may not exceed 30 dB. DIN 4109-1 also specifies similar minimum requirements for such rooms.

The puppy and its own tail …

Photo: © LIFTjournal/Dirk Müller/KI-generiert mit Firefly und ChatGPT

Let’s take a critical look at the key features of building type E. These buildings are intended to help socially weaker population groups, such as the elderly and families with children, find affordable flats. But this is where the puppy starts chasing its own tail: for example, if no lift is required by law for buildings with up to four storeys, these groups are automatically excluded by the absence of barrier freedom.

But there are also problems in higher buildings with regard to noise or health protection involving building equipment. For example, the key point of reduced component thickness for noise decoupling is a relevant topic for lift building. But taking aim at component thickness in this regard does not make sense. This is because if a lift generates a noise pressure level of 70 dB during a trip, the noise insulation dimension of the in-between component in the adjacent rooms is decisive for the noise pressure level.

Reference to the component thickness does not make sense either for another reason. In the case of lift shafts consisting of infra-lightweight concrete, lightweight concrete, wood, brickwork, etc., the component thickness is not decisive but rather the noise insulation dimension arising from the frequency emitted and surface-related mass. This is important for lift building since the noise output increases with decreasing frequencies.

Co-responsibility in the sense of personal negligence

Consequently, technical specifications for lifts for building type E have to provide particularly reliable structural descriptions. The flanking components (floors, platforms, stairs, etc.) and the location of the rooms requiring protection play an important role here.

It is important to note that the client (or body issuing a tender) should be very meticulous with the specifications. If it withholds crucial information or omits appropriate protective measures important for the success of the building or the interaction of the building with the building equipment (e.g. lift), it bears co-responsibility in terms of the Supreme Court verdict in the sense of personal negligence.

Conclusion

Lift companies or installation firms have different options for achieving the noise insulation goals pursuant to DIN 4109-1 and/or DIN 4109-5 in rooms requiring protection in lift shafts with low surface-related mass or low noise insulation dimensions. The main reason the noise insulation goals cannot be achieved in rooms requiring protection is the structure-born noise level emitted by the lift.

A practical tip to close: Information is available in the relevant standards on how the noise insulation goals can be achieved. The selection and interaction of the components subsystems play a decisive role here.

Ulrich Nees is the owner of “Aufzug-Systeme +  Beratung Ulrich Nees”