So you want to understand anti-slip ratings and R-values so you can pick safer flooring and surfaces. Anti-slip R-values are lab-tested ratings (R9 to R13) that tell you how slip-resistant a surface is when walked on at different angles, mainly for tiles and similar materials.

These ratings matter because slips are one of the most common causes of injuries, at home and at work. When you know what R9, R10, R11, R12, and R13 actually mean, you can pick the right surface for your bathroom, kitchen, outdoor steps, ramps, and even your office or warehouse, based on real conditions rather than guesswork or marketing claims.

Things you need to know:

• R-values (R9 to R13) come from a standard ramp test with oil underfoot.
• Higher R-value = higher slip resistance in that test method.
• R9 is the lowest rating in this system; R13 is the highest.
• R-values describe “shod” (with shoes) slip resistance, not barefoot performance.
• There are different tests for barefoot areas and for wet public zones.
• For homes, R9 or R10 can be fine in dry rooms; wet areas usually need R10 or R11.
• For commercial kitchens, factories, and ramps, you are usually looking at R11-R13.
• R-value is not everything: cleaning, wear, and contamination change real-world grip.
• Several countries use extra measures (like PTV, BPN, DCOF) alongside R-values.
• Always match the surface to realistic use: shoes, barefoot, water, oil, slope, traffic.

If you treat R-values as a simple “higher is safer” score without context, you can still end up with risky floors.

What anti-slip R-values actually are

So what exactly is this “R” rating?

In most product catalogs for tiles, engineered stone, and some coatings, you see something like “Slip rating: R10”. That “R” rating comes from a standard oil-ramp test (commonly DIN 51130, from Germany) that measures how a person walks on a surface at different angles while wearing safety shoes and walking on motor oil.

In the test:

• A sample of the surface (tile, stone, coating) is installed on a ramp.
• The ramp surface is covered with oil.
• A test person wearing standardized shoes walks up and down the ramp.
• The ramp angle is slowly increased until the person feels unsafe or actually slips.
• The angle range maps to R9, R10, R11, R12, or R13.

So the “R” is literally from “ramp”.

R-values are not a guess from the manufacturer; they come from a pretty tough physical test with real people on a slippery ramp.

The angle ranges for R9 to R13

The approximate angle ranges used for R-values in the ramp test look like this:

R rating	Ramp angle range (degrees)	Slip resistance level (shod, oily)
R9	> 6° to < 10°	Low
R10	≥ 10° to < 19°	Moderate
R11	≥ 19° to < 27°	High
R12	≥ 27° to < 35°	Very high
R13	≥ 35°	Extremely high

These angles are not meant to be intuitive for daily life. You probably never think “my bathroom is at 19 degrees”. What matters is:

• As the R rating increases, the tested safe angle on an oily ramp increases.
• That means under those test conditions, R13 grips far better than R9.
• But your real-world surface may be wet with water, not oil, and you might wear sneakers or go barefoot.

So R-values are a controlled way to compare products, not a perfect reflection of every real-world use.

Why R-values exist and where they are used

You might wonder why this is so standardized and why oil is involved at all.

The short version: different industries needed a consistent way to compare slip resistance because slips were causing injuries, downtime, lawsuits, and claims.

• Factories had oil or grease on floors.
• Commercial kitchens had water, oil, and food residues.
• Public buildings had wet entrances in rain or snow.
• Healthcare and care homes needed safer floors for vulnerable users.

A ramp with oil is a harsh environment that lets testers sort surfaces clearly. It is not perfect for every scenario, but it is repeatable, so manufacturers and safety experts can:

• Classify surfaces.
• Match them to typical uses.
• Create building codes and guidelines.

R-values came out of industrial safety needs, then spread into commercial building design, and now they show up in residential catalogs too.

In many countries, R-values are referenced in:

• Workplace safety rules.
• Commercial kitchen standards.
• Accessible design for ramps and stairs.
• Guidance for public bathrooms, pools, and changing areas.

You might buy tiles online and see “R10” without any explanation. That is where this background helps: you can map that number to your real conditions and decide if it is enough.

The limits of R-values (what they do not tell you)

R-values sound clear and simple. Higher is better, right?

Not always.

The R-value has some built-in limits that you should keep in mind.

1. It is an oil test, not a water test

The ramp is contaminated with oil, not water or soap. Some surfaces react differently to oil compared to water.

For example:

• A surface with a very fine texture might grip well in water but lose performance with oil.
• A surface with a specific micro-structure might do better with oil than with soapy water.

So if your main risk is soapy shower water, the R rating you see might not fully reflect that. That is why there is another test for barefoot areas (DIN 51097, often used around pools and showers) that uses water instead of oil.

2. It is for people wearing shoes

The R test uses standard safety shoes. Your home bathroom floor will often be used barefoot. Your office might involve dress shoes with much smoother soles than safety footwear.

Barefoot and soft soles grip in different ways. So:

• R-values are more helpful for shod, work-like environments.
• For barefoot zones (pools, spas, home showers) look for extra barefoot classifications like “A”, “B”, or “C”.

If your main risk area is a barefoot shower, the barefoot rating matters more than the R-value.

3. It is a lab test, not your cleaning routine

In the lab, the tile is new, clean, and prepared in a repeatable way. In daily life you have:

• Dirt, dust, and residual cleaning agents.
• Wear that smooths textured surfaces over time.
• Improper cleaning that leaves films and residues.

A tile that leaves the factory with a great R rating can turn into a slippery surface if it is polished by foot traffic and cleaned with a product that leaves a glossy film.

This is one of the biggest gaps between product data sheets and actual floors. Maintenance is a key part of real slip resistance.

4. It does not include all possible slip tests

R-values are only one part of a broader testing world. You will often see:

• PTV or BPN (Pendulum Test Value / British Pendulum Number).
• DCOF (Dynamic Coefficient of Friction; for example ANSI A326.3 in North America).
• Static Coefficient of Friction tests.

Each test method has:

• Different equipment.
• Different surfaces (wet vs dry).
• Different thresholds for “safe enough”.

R-values do not “translate” perfectly to PTV or DCOF, but together they give a better picture of actual grip.

Typical use cases for each R rating

You probably care less about the exact lab protocol and more about one thing: “What R-value should I aim for in area X?”

This is where real-world patterns and local regulations come in. Exact rules vary by country, but the general patterns look like this.

R9: low slip resistance

R9 is the lowest rating in this scale. It is not “bad”, but it is not intended for areas with much moisture or contamination.

Typical uses:

• Dry indoor living rooms.
• Office spaces without wet processes.
• Bedrooms and corridors in dry conditions.
• Walls and vertical surfaces (no foot traffic).

Risks if you pick R9 for wet zones:

• In bathrooms, any water on the floor can create a slip risk, especially for older users or children.
• In kitchens, oil splashes combined with smooth R9 surfaces create dangerous spots near cookers.

In general, treat R9 as “dry interior use” unless your local code says otherwise.

R10: moderate slip resistance

R10 is a common middle-ground rating. Many residential tiles fall in this range.

Typical uses:

• Home kitchens and bathrooms with decent cleaning routines.
• Entrance halls that may get slightly wet from shoes.
• Commercial spaces with limited water or oil, like offices and dry retail spaces.

In a home setting, R10 often feels like a good balance between safety and cleanability. The surface is not too rough, but it gives more grip than many polished finishes.

In a busier commercial setting, R10 can be fine in mostly dry areas, but in food zones or where water is frequent, you usually want R11 or higher.

R11: high slip resistance

R11 pushes into clear safety territory, especially for places where floors get wet often.

Typical uses:

• Commercial kitchens with some oil and water.
• Workshops or production areas with limited fluids.
• Outdoor terraces and balconies that get rained on.
• Home shower areas and bathrooms where safety is a priority.
• Inclined access areas with occasional moisture.

From a user comfort view, R11 has a more pronounced texture. Some people like that; some find it harder to clean. For high-risk spots though, it is often a smart choice.

R12: very high slip resistance

R12 is typically used in tougher environments.

Typical uses:

• Commercial kitchens with plenty of oil and fat on the floor.
• Industrial areas with frequent contamination.
• Loading bays and ramps subject to rain and oil.
• Food processing areas with fats and liquids.

R12 surfaces often have a strong texture. Cleaning gets more demanding. There is always a trade-off: increased grip vs easier cleaning and maintenance.

R13: extremely high slip resistance

R13 is the top of the current scale. Surfaces in this class are designed for heavy, messy environments where slips can cause serious injury and downtime.

Typical uses:

• Heavy industrial plants with oil, grease, and chemicals.
• Some slaughterhouses and food plants.
• Strict safety zones with strong contamination risk.

You probably will not specify R13 for your living room or even your usual office. It often feels quite rough underfoot. But where safety authorities and insurance policies demand it, R13 can be essential.

Think of R13 as “industrial-grade grip” rather than something you casually install in a guest bathroom.

Barefoot slip ratings: A, B, C

For barefoot zones, especially around pools, saunas, and some showers, another rating system often shows up: A, B, C.

These come from DIN 51097, which is similar in idea to the oil ramp test but:

• Uses water instead of oil.
• Uses barefoot test persons.
• Applies to barefoot areas only.

The ratings:

Barefoot class	Ramp angle range (degrees)	Typical areas
A	≥ 12° to < 18°	Dry changing rooms, some indoor barefoot walkways
B	≥ 18° to < 24°	Pool surrounds, showers, spa walkways
C	≥ 24°	Pool steps, steeply inclined areas into water

In practice:

• A is a basic barefoot rating for areas that may only get slightly wet.
• B is common for pool edges and shared showers, where serious wet conditions exist.
• C is for higher risk spots such as the steps going into a pool.

If your main risk is barefoot slips, such as in a domestic wet room, look for these classes along with the R rating.

How tech fits in: sensors, testing devices, and data

Let us bring this a bit closer to the technology world, since your niche is technology and safety often merges with measurement and data.

Anti-slip ratings are not just about a person walking on a ramp. New technology is reshaping how we assess and monitor slip resistance.

Portable tribometers and pendulum testers

Tribometers are devices that measure friction between a standardized slider and the floor surface. The British Pendulum Tester, for instance, has a swinging arm and a rubber slider. The loss of energy when the slider contacts the surface translates into a Pendulum Test Value (PTV).

Key points:

• They give an objective number that can be repeated across locations.
• They can test wet and dry conditions.
• They are widely used in investigations after slip accidents.

In terms of technology, modern tribometers:

• Include digital readouts and data logging.
• Connect to mobile apps for reporting.
• Support scheduled testing to track changes over time.

This connects flooring to safety analytics: safety teams can see how friction values change with seasons, cleaning products, or wear patterns.

IoT sensors and smart building systems

While not yet everywhere, there is growing interest in using IoT sensors to:

• Detect wet floors (moisture sensors near entrances and restrooms).
• Trigger alerts to cleaning staff or building managers.
• Log patterns of moisture over time for risk planning.

For instance:

• A sensor near an entrance can detect when snow or rain creates puddles inside, sending real-time alerts.
• Occupancy sensors can combine with cleaning schedules so high-traffic areas receive more frequent checks.

These systems do not replace R-values, but they support them by making real conditions visible.

Computer vision and slip-risk prediction

In some pilot projects, cameras and AI models analyze floor traffic and detect:

• Standing water or spills based on visual cues.
• Patterns of near-falls or unusual gait changes using video analytics.

Imagine:

• Cameras watching a supermarket aisle spot a spill and automatically alert staff.
• Computer vision flags spots where people repeatedly slow down or adjust their steps, hinting at hidden grip problems.

Again, these do not change the R rating of a tile, but they help manage real slip risk dynamically.

Choosing the right R-value for your project

Now let us get practical. How do you pick the right R rating when you are planning or evaluating a floor?

Think in terms of:

• Where it is.
• Who uses it.
• What gets on the floor.
• How steep it is.
• How it will be cleaned.

1. Identify the area and user type

Ask yourself:

• Is this a home, office, factory, healthcare setting, or public area?
• Do children, older adults, or people with mobility challenges use it often?
• Is it mainly used with shoes or barefoot?

Higher risk users call for higher slip resistance, especially where water or other contaminants appear regularly.

2. Map typical contaminants

Think through what actually ends up on the floor:

• Mostly dry dust: Lower R-values may be fine.
• Water and some splashes (home bathroom, home kitchen): R10 or R11 is safer.
• Grease, oil, fat (commercial kitchen, garage, shop): R11, R12, or R13, depending on severity.

If in doubt, assume more contamination than less. For instance, a home kitchen might not see industrial quantities of oil, but repeated small splashes near the stove still matter.

3. Check slope or ramps

Any incline adds risk. On ramps you are often required to go higher on the R scale.

Rough guide:

• Gentle slopes with water only: R11 or higher is often recommended.
• Slopes with oil or heavy contamination: R12 or R13.

Local rules vary, so always check guidance where you are, especially for public or workplace spaces.

4. Balance cleaning with grip

Higher R ratings usually come with rougher textures. These can:

• Trap dirt and spills.
• Take longer to clean.
• Need specific cleaning tools or products.

You do not want a floor that is safe on day one but impossible to keep clean. Dirty floors can be both unsafe and unpleasant.

Talk to flooring suppliers about:

• Recommended cleaning products.
• Maintenance intervals.
• How the slip rating holds up over time.

A slightly lower R rating that is cleaned properly often beats a higher R rating that never gets maintained.

How R-values relate to other slip metrics

Let us look briefly at how R-values connect to other common measures. These connections are not exact, but they help when you see different numbers from different tests.

Pendulum Test Value (PTV / BPN)

The pendulum tester measures slip resistance with a swinging arm and rubber slider. It outputs a number:

• PTV < 24: high slip risk (wet).
• PTV 25-35: moderate risk.
• PTV > 36: low risk (wet) in many guidelines.

Very rough approximate picture (not a strict rule):

R rating	Typical PTV (wet) range
R9	Maybe < 25 in many cases
R10	Often around 25-35
R11	Often ≥ 36
R12-R13	Frequently > 40, sometimes much higher

Some surfaces break these patterns, so you cannot just convert one to another, but you can treat them as separate pieces of evidence.

DCOF (Dynamic Coefficient of Friction)

In North America, ANSI A326.3 uses DCOF to rate ceramic tile. A common threshold for interior tile in wet areas is:

• DCOF ≥ 0.42 (wet) for many interior applications.

Again, DCOF is measured differently, with a mechanical device under standard conditions. An R11 tile often has a DCOF that meets or exceeds that typical requirement, but you should look at both numbers if possible.

Common mistakes when using R-values

A few patterns show up again and again in projects:

Mistake 1: “Higher R is always better”

Installing R13 everywhere sounds safe, but it can backfire:

• High texture can trap dirt; dirty floors become slippery and unpleasant.
• High roughness can be uncomfortable for barefoot areas.
• Noise from trolleys or carts can increase on rough floors.
• Wheelchairs and cleaning machines may not move smoothly.

Choose the lowest R rating that still gives acceptable safety in your actual conditions. That is often R10 or R11 in many non-industrial projects.

Mistake 2: Ignoring wet and contamination patterns

People sometimes focus only on the room label:

• “It is a kitchen, so any tile is fine.”
• “It is just a bathroom, not a factory.”

That thinking misses:

• Local wet zones, such as directly in front of the sink or shower.
• Transition areas where water from outside is tracked in.
• Specific spots like the area in front of a combi oven or fryer in a commercial kitchen.

Consider zoning:

• Higher R surfaces where contamination is frequent.
• Moderate R surfaces elsewhere.
• Appropriate mats or drainage where needed.

Mistake 3: Forgetting about wear and cleaning

Everything ages. Textured surfaces can smooth out in busy areas, especially near doors or main walkways.

Add on top:

• Polishing cleaning products that fill micro-texture and make floors glossy.
• Incorrect pads on floor machines that polish rather than clean.

The result:

• A floor that still has “R11” on the data sheet but behaves like R9 in real life.

Periodic on-site slip testing (using a pendulum tester or other tribometer) gives you real data, not just the original product rating.

How to read a product slip resistance label

When you look at a technical data sheet or web listing, slip resistance lines can seem confusing. Here is what to look for and how to interpret it.

A typical tile data line might say:

• Slip resistance (shod): DIN 51130, R11
• Slip resistance (barefoot): DIN 51097, class B
• DCOF (ANSI A326.3): wet 0.45

Interpretation:

• R11: Suitable for many wet, shod areas, such as commercial kitchens, entrances, and some ramps.
• Class B: Suitable for barefoot wet areas like pool edges and showers.
• DCOF 0.45 wet: Meets many interior wet-floor guidelines.

If the sheet only shows “R9” and nothing else, think:

• Probably only safe in dry conditions.
• Ask the supplier for more data if you plan to install it in any wet or contaminated area.

If a critical floor has no clear slip resistance data, treat that as a red flag and push for better information or a different product.

Simple planning examples

To ground this, here are short scenarios and choices.

Example 1: Home bathroom and shower

Conditions:

• Regular water on the floor, soap, shampoo residue.
• Users: adults and children, barefoot.
• Flat floor with no ramps.

Reasonable choices:

• Bathroom main floor: R10 or R11.
• Shower area: R11 with barefoot class B or C if possible.
• Avoid highly polished R9 tiles on the main wet areas.

Cleaning:

• Use cleaners that do not leave a waxy or glossy film.
• Rinse well to remove residues.

Example 2: Small restaurant kitchen

Conditions:

• Water, oil, and food spills.
• Staff wearing work shoes with slip-resistant soles.
• Flat floor, maybe a short back-of-house ramp.

Reasonable choices:

• Kitchen floor: R11 or R12.
• Ramps or dishwashing area with heavy contamination: R12, possibly R13.

Cleaning:

• Daily scrub with suitable degreaser.
• Occasional on-site slip test if regulations or insurance require it.

Example 3: Office entrance and lobby

Conditions:

• People in dress shoes and sneakers.
• Water from rain brought in by shoes.
• Flat surface plus possibly small slopes or steps.

Reasonable choices:

• Inside lobby: R10 or R11, with absorbent entrance matting near doors.
• External steps: R11, maybe with extra nosing strips or anti-slip treads.

Cleaning:

• Regular mopping with neutral cleaner.
• Extra attention during wet weather.

Practical tip: build a simple “slip risk checklist” for every floor

To turn all of this into something you actually use, create a one-page checklist for any new floor or major refurbishment.

For each area, write down:

• Location: e.g., “Ground floor restroom”, “Warehouse ramp”, “Main entrance”.
• Users: staff, visitors, children, older adults, barefoot, wheelchair users.
• Typical contaminants: dry only, water, soap, oil, fat, powders.
• Slope: flat, gentle slope, steep ramp, steps.
• Slip data target: e.g., “R10 minimum”, “R11 + barefoot class B”, “PTV ≥ 36 wet”.
• Planned cleaning method: product, frequency, equipment.
• Review date: when to check wear and possibly retest slip resistance.

Then, when you compare products or talk to suppliers, you are not just asking “What R-value does this tile have?” You are asking “Does this tile meet R11, barefoot class B, and DCOF 0.42 wet, and can we clean it effectively?”

That shift alone makes your surfaces safer and your choices more defensible if questions arise later.