Anti-slip shower tray ratings: DIN 51097 and R classes explained
Anyone designing or renovating a bathroom sooner or later comes across some rather cryptic codes: DIN 51097, or R10, R11. These are the two systems used to measure the anti-slip rating of a shower tray, in other words how well its surface resists slipping when wet. Understanding the difference isn’t a technicality for specialists only: it’s what determines the real safety of anyone stepping into the shower barefoot, every day. In this guide we explain how to read a shower tray’s slip resistance rating according to DIN 51097 (classes A, B, C) and DIN 51130 (classes R9-R13), and which rating to choose for a home bathroom, a hotel, a care home or a poolside area.
What an anti-slip shower tray rating is and why it really matters
A shower tray’s anti-slip rating is a standardised value that describes the friction coefficient of a surface in wet conditions. It isn’t a vague claim such as “textured surface” or “anti-slip treatment”: it’s a figure measured in a laboratory using a precise test method, which allows different materials to be compared objectively. For a shower tray this is particularly important because the conditions of use are among the riskiest in any home: a wet surface, soaps and body products that reduce friction even further, bare feet and often quick movements in a confined space. It’s no surprise that a large share of accidents in the home bathroom happen in or near the shower tray. Checking a shower tray’s slip resistance rating before buying is therefore not a designer’s whim but a genuine safety criterion, in a professional specification just as much as in a private purchase.
DIN 51097: classes A, B and C for barefoot anti-slip shower trays
When it comes to the anti-slip rating of shower trays in barefoot areas, the technical reference is the German standard DIN 51097, which measures slip resistance with an inclined ramp test: an operator walks barefoot on a surface wetted with soapy water, and the ramp is gradually tilted until the point of slipping. The angle recorded determines the classification.
Class A (12°-18°)
Suitable for changing rooms and barefoot access areas, where the floor is only occasionally wet.
Class B (18°-24°)
This is the most common benchmark for anti-slip shower trays in homes and hotels, because the surface is continuously wet and the foot moves within a small area. It’s the level found, for example, in the CSA resin shower tray collection, certified to DIN 51097.
Class C (over 24°)
Reserved for extreme settings such as submerged sloping pool edges, swimming pool steps and areas where water can pool: a level of safety rarely needed for a domestic shower tray, but one that may be required in sports facilities or wellness centres.
DIN 51130: R9-R13 ratings and slip resistance when wearing shoes
Alongside DIN 51097 there is DIN 51130, which instead classifies slip resistance for people wearing shoes, using a test with engine oil instead of soapy water. The classes range from R9 (minimum grip, suitable for dry indoor areas) to R13 (maximum grip, typical of industrial ramps or areas with a heavy presence of slippery substances). For the shower tray itself the R scale is less relevant, since you walk barefoot in the shower, but it becomes useful for the surrounding areas: the floor around the shower, the walkway leading to it, changing rooms where people walk in shoes before taking them off. A coherent project takes both standards into account, also comparing the materials available for CSA shower trays: DIN 51097 for the tray surface, DIN 51130 for the surrounding floors.
Which anti-slip shower tray rating for homes, hotels, care homes or poolside areas
Choosing the right anti-slip rating for a shower tray depends on the intended use, how often it will be used and the profile of the people who will use the space.
Home bathrooms
For a standard home bathroom, class B generally strikes the right balance between safety and ease of cleaning: a surface with too pronounced a texture traps limescale and soap residue more easily, whereas class B already provides high grip without making daily maintenance harder. The CSA stone-effect shower trays also build the anti-slip texture directly into the surface finish.
Hotels and hospitality
Where the shower tray is used by different people every day and maintenance is not always prompt, class B should again be the minimum, with class C worth considering for the property’s wellness areas, indoor spa or poolside.
Care homes and facilities for the elderly
For care homes, retirement homes and, more generally, spaces for older people or those with reduced mobility, the shower tray’s slip resistance rating should form part of a wider accessibility project: a floor-level tray, a compact footprint and no changes in level. In Italy the regulatory reference is Ministerial Decree DM 236/1989 on the removal of architectural barriers, which works alongside the slip resistance requirements. On this front, CSA shower enclosures for disabled and elderly users are designed precisely to meet both needs together.
Poolside and wellness areas
Where the surface stays wet continuously and the risk of standing water is higher, the usual step up is to class C, the only one able to guarantee sufficient grip even when water is standing.
How to check a shower tray’s anti-slip rating on the data sheet and in the specification
When choosing a product, the shower tray’s slip resistance rating must appear explicitly on the manufacturer’s technical data sheet, stating the reference standard (DIN 51097) and the class achieved (A, B or C). A generic statement such as “anti-slip surface”, with no classification, cannot be verified and should not be accepted in a professional specification. For public projects or hospitality facilities it is good practice to request the test certificate issued by the laboratory, so as to have supporting documentation in the event of inspections or disputes. It’s worth remembering that a shower tray’s anti-slip rating is not a permanent property: limescale, aggressive cleaning products and wear can reduce the original friction coefficient over time, which is why cleaning with pH-neutral products is an integral part of the product’s safety, not just its appearance. CSA cut-to-size, made-to-measure shower trays also retain their anti-slip certification after cutting, a point always worth checking at specification stage.
FAQ
What is the minimum anti-slip rating recommended for a shower tray in a home bathroom?
For a standard home bathroom, class B under DIN 51097 is generally considered the minimum recommended level, because it ensures high grip for bare feet on a wet surface.
Are a shower tray’s anti-slip rating and the R rating the same thing?
No. The anti-slip rating under DIN 51097 (A, B, C) measures slip resistance for bare feet with soapy water, while the R classes of DIN 51130 measure slip resistance for people wearing shoes, using oil: they are two separate standards designed for different conditions of use.
Does a resin or stone-effect shower tray have a better anti-slip rating than traditional ceramic?
It depends more on the specific finish than on the material itself: many resin and stone-effect porcelain collections available today are certified class B under DIN 51097, a level equal to or higher than many traditional ceramic tiles, with the added benefit of building the anti-slip texture into the surface design.
How do I choose the anti-slip shower tray rating for a care home or facility for the elderly?
For care homes, the shower tray’s anti-slip rating should be chosen as part of a complete accessibility project, including floor-level trays and walk-in shower solutions, dimensions compliant with DM 236/1989 (in Italy) and, where necessary, class B or C surfaces depending on the level of continuous moisture expected in the room.
In short, a shower tray’s anti-slip rating should never be chosen at random or left to a generic marketing label: it is a verifiable technical figure, governed by precise standards, that varies with the context of use. For a home bathroom, class B under DIN 51097 is almost always the most balanced choice; for hotels, care homes and wellness areas the required level may be higher, and should be assessed together with the other aspects of the project, from accessibility to long-term maintenance. Comparing the technical data sheets of materials, asking for certification when needed and not trusting generic labels remains the most practical way to ensure, day after day, the safety of anyone stepping into the shower. Contact us today!
