DIN 18040 – Specifications for marking stair treads

DIN 18040 is Germany’s basic standard for barrier-free planning and building and comprises three parts: Part 1: Publicly accessible buildings (2010-10 edition). Part 2: Dwellings (2011-09 edition) Part 3: Public transport and open space (2014-12 edition). Within the standard, necessary structural and technical requirements are discussed in order to make buildings and facilities barrier-free. [1, 2] If the standard is complied with, one can be sure to act in accordance with the current state of the art and thus in a legally secure and humane manner. Step marking Parts of the requirements also refer to the construction of stairs and their design. A focus is on the marking of steps to improve perception. According to the standard, high-contrast step markings must be made at the tread and riser [3]. The standard recommends the following values/dimensions:

• Step leading edge 4-5 cm wide [3].
• Top edge of riser 1-2 cm wide [3].
• Contrast value K > 0.5 [3].

The contrast value must be complied with in relation to the steps but also in relation to landings and the floor. In public buildings, step leading edge markings are mandatory on every step of stairs with up to three steps and stairs that begin or end freely in the room. In stairwells, the requirement only applies to the first and last step, but it is sensible to mark all steps here as well. The marking is to be carried out in full width and all around [4]. It is important that the contrast is not chosen in terms of colour, but as a contrast in luminance/brightness. Complementary colours, for example, would be unsuitable, despite high colour contrast, as there is no difference in brightness [5]. Luminance contrast can be calculated using the Michelson formula: K = (  L_hF – L_dF ) / ( L_hF + L_dF )                     [5] K = luminance contrast L_hF = luminance of the lighter colour L_dF = luminance of the darker colour For the required contrast value of 0.5, it follows that the luminance of the lighter colour (L_hF) must be at least 3 x higher than the luminance of the darker colour (L_dF)_. Reflections can create irritating shadows that simulate a non-existent contrast. Reflective elements, such as stainless steel, should therefore be avoided as step edge markings. Matt and diffusely reflecting surfaces are better [5]. Since soiling leads to a strong reduction of the contrast value, the minimum contrasts are to be understood as maintenance values [5]. Already during installation, care should be taken to ensure that the markings are easy to keep clean. Various measuring instruments are available for determining the contrast value. First approximations can be determined with the help of the Michelson formula. The necessary values can be determined using RAL value specifications or contrast determination charts (e.g. from the German Association for the Blind and Visually Impaired, available on the DBSV website). Safety-Stair step profile CleanGrip Safety-Stair Profile CleanGrip offer a cost-effective and simple solution for retrofitting stairs and steps. The profile is made of anodised aluminium. The strip width of the horizontal marking (tread) is 4 cm; the width of the vertical marking (riser) is 2.5 cm – thus fulfilling the requirements of standard 18040 with regard to marking dimensions. In combination with our tried-and-tested CleanGrip anti-slip covering, the profiles remain visually clean and visible for a long time. Regular cleaning ensures that the optical properties are maintained for years to come. You can find our complete range of profiles here. Sources

1. Beuth Verlag, https://www.beuth.de/de/norm/din-18040-1/133692028, retrieval date 06.01.2020
2. DGUV, https://www.dguv.de/barrierefrei/grundlagen/gesetze/standards/din18040/index.jsp, retrieval date 06.01.2020
3. HyperJoint GmbH, https://www.din18040.de/, retrieval date 06.01.2020
4. HyperJoint GmbH, https://nullbarriere.de/din18040-1.htm, retrieval date 06.01.2020
5. Technical brochure of the German Association for the Blind and Visually Impaired e.V. (DBSV): Kontrastreiche Gestaltung öffentlich zugänglicher Gebäude, Edition 1, 2016