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The most important fact at first: the new version of the German DIN 18040 series „Barrierefreies Bauen - Planungsgrundlagen (Barrier-free construction – planning principles)” has still not been published.
As a result, the current versions of
- Teil 1 Öffentlich zugängliche Gebäude October 2010
Part 1 Publicly accessible buildings - Teil 2 Wohnungen September 2011
Part 2 Apartments - Teil 3 Öffentlicher Verkehrs- und Freiraum December 2014
Part 3 Public transport and open space
This circumstance is evident in the German regulation Muster-Verwaltungsvorschrift Technische Baubestimmungen (model administrative regulation Technical Building Regulations) 2024/1 (MVV TB 2024/1) published in August 2024. In section A.4 „Sicherheit und Barrierefreiheit (Safety and accessibility during use)“, it still refers to the (old) versions. That means, based on current knowledge, there will not be many changes with regard to the barrier-free requirements for windows.
In other words, the rules of the game have not changed in recent years. Furthermore, there is no reference to the European standard DIN EN 17210.
Status of standardisation work
Nevertheless, changes are pending. With the publication of the overarching European DIN EN 17210 "„Barrierefreiheit und Nutzbarkeit der gebauten Umwelt – Funktionale Anforderungen (Accessibility and usability of the built environment - Functional requirements)" in 2021, a revision or adaptation of the national DIN 18040 series of standards became necessary. It should be noted with regard to DIN EN 17210 that it primarily formulates protection goals and contains recommendations. The functional requirements set out there are therefore formulated purely qualitatively, i.e. without concrete quantitative information and thus difficult for practical application. This standard is also already being revised again.
There were (originally) three years available for the revision or, more accurately, adaptation of the national standard series DIN 18040. For this purpose, three drafts were published with the following versions:
- Teil 1 Öffentlich zugängliche Gebäude February 2023
Part 1 Publicly accessible buildings - Teil 2 Wohnungen February 2023
Part 2 Apartments - Teil 3 Öffentlicher Verkehrs- und Freiraum January 2023
Part 3 Public transport and open space
It should be noted that normative requirements for the accessibility of windows and French doors can only be found in Part 2. Naturally, as with previous revisions, there were a large number of objections and comments. As a result, the new versions are not yet available. A key reason for this was that at the beginning of the three-year period, the standards committee was busy translating the more than 300-page EN 17210 into German.
It is not possible to say exactly when the revised series of standards will actually be published at this point in time, but it will definitely not be this year. It should be remembered that time will also pass between the publication of the standards and their inclusion in the VV TB of the individual federal states.
This means that the future DIN 18040 series of standards will become an “application standard” for DIN EN 17210, which sets out the technical implementation of the European requirements and provides examples of solutions, i.e. shows how the verbal protection goals are implemented in built reality.
Changes from the drafts
Basically, there are only specific changes or additions for windows and French doors. The structure (table of contents, illustrations, etc.) remains essentially the same. Some sections, such as 5.3.2 "Windows" (only in Part 2), have been adopted word for word. The essential requirements for doors and windows and their installation position have not been significantly changed either - with the exception of the information on the maximum permissible threshold height. As expected, the revision also increased the scope of the standard, which is not surprising since the European basis DIN EN 17210 has an impressive 324 pages.
Many of the normative requirements are not primarily directed at the component itself, but at accessibility and reachability. These are largely determined by the positioning in the building structure. Ultimately, barrier-free construction is primarily a planning task that should be carried out by specialist planners. The ift technical information BA-02/1 "Recommendations for implementing barrier-free construction in residential construction with windows and doors" provides information on this. This publication shows conflicting objectives and practical solutions.
The most important changes for windows are listed below. In Section 1, Scope of application, the wording is slightly different from the previous standard: "This document is to be used for new buildings. The document is applicable analogously to the planning of conversions or modernizations."
We understand this to mean that the protection goals specified in the standard should also be aimed for in old buildings. However, due to general conditions, in particular structural circumstances, this cannot always and everywhere be fully achieved without massive intervention in the building structure. Which of the requirements can be implemented must be decided on a case-by-case basis. This decision is basically a matter of weighing things up and seeking a compromise and should, if possible, be made with all those involved (client, planner and manufacturer/fitter).
Section 3 "Terms" in the draft version has been significantly expanded to now 15 terms (in Part 1). Here you will find definitions for the following aspects for the first time
3.11 Threshold
"Horizontal part on the lower door frame over which the door leaf rests and which separates the floor between two adjacent areas"
[Source: DIN EN 12519:2019-02, 3.58, modified – Note 1 to the term removed]
3.12 Level transition
"Horizontal transition between two structural levels with a tolerance-related height offset of max. 4 mm" and note 1 to the term: "Transition rails and transition profiles are permitted."
This means that the misleading term "threshold-free" has been consistently replaced by "level transition" and provided with a tolerance specification. In addition, the topic of tolerances, which is often discussed in practice, has been made more concrete and reference has been made for the first time and as an example to DIN 18202 "Tolerances in building construction – Structures" (undated). The following note can be found in both parts of E DIN 18040 in sections 4 and 5:
Section 4 specifies "finished dimensions. Finished dimensions include tolerances" (see e.g. DIN 18202). Tolerances must not result in required minimum dimensions being undercut or maximum dimensions being exceeded. They must therefore be taken into account in the planning process. Deviations in the design can only be tolerated if the function intended in this document is achieved."
In many cases, the finished dimensions mentioned are the sum of several individual dimensions. These usually result from various individual trades with their own specifications and tolerances, which can also add up in an unfavorable way. As a result, it is conceivable that mathematical deviations can arise that do not correlate with the barrier-free protection goal. A classic example of this is the specification of the handle height. It is advisable to specify tighter tolerance specifications or higher execution accuracy in the planning so that the specified protection goal can be reliably achieved.
Threshold design of doors
It is already becoming apparent that the wording on threshold design and its effects on the construction will again be the focus of the discussions (as in previous rounds of objections). Table 1 compares the wording on the requirements in the various standards. If the "new" wording is compared with the "old" one, the following is noticeable:
- The text is significantly longer
- "are not permitted" has become "if possible, should"
- The term "threshold-free" has been replaced with "level"
- The exception for the threshold height has been reduced from 2 cm to 1 cm, although this measurement is not described precisely.
- The wording "Lower door stops are not permitted. If they are essential for technical reasons..." is replaced by "If door stops cannot be avoided, the threshold height may..."
- The term "rollover capability and tripping hazard" has been added
- The terms "beveled or rounded" have been mentioned, but not clearly regulated
Practical advice on threshold height
In order to counteract the frequent "millimeter discussions" regarding threshold height and to be able to assign a reproducible value to the formulated protection goal of "easily rollover", ift Rosenheim has published the ift guideline "BA-01/1 Determination and classification of the rollover capability of thresholds", which enables the rollover capability to be determined and classified. As a result, different threshold designs can be objectively compared and quantified and put out to tender. To avoid discussions or disputes, the contractor should communicate the technically feasible threshold height before implementation and have it approved by the client.
Summary
The "old" versions of DIN 18040 are currently still valid. The new versions of the three parts of this series of standards are to be published with the same issue date - as things stand at the moment. Part 3, "Public transport and open space", which is of less interest for building construction, has largely been discussed in detail. Part 1, "Publicly accessible buildings", is almost complete. Part 2, "Apartments", should be able to be implemented relatively quickly, as most of the requirements are identical to those in Part 1. Nevertheless, it will still be some time before it is included in the VV TB of the respective federal states.
The main change – which the industry will probably have to adapt to – is the change in the threshold height to 10 mm. We are talking about the exception here. The aim is to achieve a level transition. The fact is, however, that the classic four-sided stop seal will then hardly be technically feasible.
Literature
- DIN 18040-1:2010-10
Barrierefreies Bauen – Planungsgrundlagen –
Teil 1: Öffentlich zugängliche Gebäude
DIN Media GmbH, Berlin, https://www.dinmedia.de/de - DIN 18040-2:2011-09
Barrierefreies Bauen – Planungsgrundlagen –
Teil 2: Wohnungen
DIN Media GmbH, Berlin, https://www.dinmedia.de/de - DIN 18040-3:2014-12
Barrierefreies Bauen – Planungsgrundlagen –
Teil 3: Wohnungen
DIN Media GmbH, Berlin, https://www.dinmedia.de/de - DIN EN 17210:2021-08
Barrierefreiheit und Nutzbarkeit der gebauten Umwelt – Funktionale Anforderungen
DIN Media GmbH, Berlin, https://www.dinmedia.de/de - E DIN 18040-1:2023-02
Barrierefreies Bauen – Planungsgrundlagen –
Teil 1: Öffentlich zugängliche Gebäude
DIN Media GmbH, Berlin, https://www.dinmedia.de/de - E DIN 18040-2:2023-02
Barrierefreies Bauen – Planungsgrundlagen –
Teil 2: Wohnungen
DIN Media GmbH, Berlin, https://www.dinmedia.de/de - E DIN 18040-3:2023-01
Barrierefreies Bauen – Planungsgrundlagen –
Teil 3: Wohnungen
DIN Media GmbH, Berlin, https://www.dinmedia.de/de
Knut Junge
Dipl.-Ing. (FH) Knut Junge has been working at ift Rosenheim since 2002. He is an employee of the ift Centre of Technical Experts as well as a member of standards committees and bodies for barrier-free construction.