An AC rating is one of the few flooring numbers a buyer can compare without opening a test report. It is also widely misused. A laminate datasheet may declare AC4, a vinyl tile datasheet may claim AC5, and a quotation may present both as the same kind of durability score. They are not. One is an abrasion class defined in EN 13329 for laminate floor coverings. The other is usually a borrowed label with no defined meaning for a resilient product. This guide separates the two systems and shows how to write the requirement into a tender so every supplier prices the same floor.
Two classification systems, one label
AC1 to AC5 are abrasion classes. They sit inside EN 13329, the European product standard for laminate floor coverings, and they describe how a laminate surface performs in one specific wear test. The class is a property of the laminate construction: a decorative print, a transparent overlay and a core board, tested as a composite.
Resilient floors, which include luxury vinyl tile, sheet vinyl, rubber, linoleum and cork, are classified differently. ISO 10874 sets out use classes: 21 to 23 for domestic areas, 31 to 34 for commercial areas and 41 to 43 for light industrial areas. The first digit describes the intensity band, the second the level within it. A product can carry a combined declaration such as 23/33, meaning it is rated for both heavy domestic and heavy commercial use. Older datasheets may still cite EN 685, the predecessor standard, with the same class numbers.
The confusion starts when a vinyl supplier quotes AC4 or AC5. EN 13329 defines the abrasion class for laminate constructions, and the test is written around a laminate’s surface layer. Running a similar abrasion test on vinyl and relabelling the result as an AC class has no defined equivalence. It may be a genuine test result, but it is not the same claim. Treat it as shorthand until the supplier names the method, the specimen and the result.
That does not make one system better. It makes them different questions. A laminate buyer needs the EN 13329 class. A vinyl buyer needs the ISO 10874 class plus a wear layer figure. Asking for both on every product creates a datasheet that looks complete and compares nothing.
What the abrasion test measures, and what it misses
How the test works
The sample is a small laminate plank or tile. Rotating abrasive wheels run over the surface under a set load, and the machine counts revolutions until the decorative layer becomes visible. The cycle count is banded into AC1 to AC5, and a higher class means more revolutions before the surface layer fails in that test.
What it does not predict
Abrasion is one wear mechanism. The test says little about indentation from a table leg or a pallet, impact from a dropped tool, water reaching the core, joint integrity under load, staining, colour change or cleaning chemical damage. Nor does it test the floor as installed. A specimen is flat, clean and fully supported; a real floor sits on a subfloor with moisture, flatness and movement of its own. A seam or an edge is where water and movement usually do the damage, not the middle of a plank.
The commercial consequence
Specifying AC5 for a lobby does not make the lobby floor water-resistant. If the entrance takes rain and grit, a high-abrasion laminate can still swell at the joints while the surface shows almost no wear. In a dry back office, AC3 laminate may last the whole tenancy with no visible abrasion at all. The class is useful, but only for the failure mode it measures.
Reading a use class properly
ISO 10874 is a statement of fitness for a use intensity, not a league table across materials. Two class 33 products can be built very differently: one may be a thin vinyl tile with a modest wear layer, another a thicker tile with a substantial one. Both can hold class 33 while behaving differently under a chair castor, a trolley or a dropped knife.
Read the class as a minimum, then check the supporting characteristics that matter in the room: residual indentation, dimensional stability, castor chair suitability, stain and chemical resistance, and slip performance. Ask for the declared class in writing, with the standard named. A datasheet that says commercial grade without a class number is not making a comparable claim, however confident the wording.
Classes 41 to 43 are light industrial, not heavy industrial. It covers workshops, assembly and storage with moderate loads. It does not describe a plant with steel wheels, hot metal or continuous chemical spillage. If the process is heavier than the class, the class is not a defence.
Mapping room types to realistic classes
Use this as a starting schedule, then verify each line against the product datasheet and the actual traffic pattern.
| Area | Realistic ISO 10874 class | What to check on the datasheet |
|---|---|---|
| Rental bedroom or living room | 23 | Abrasion or wear layer, stain resistance, underlay and sound |
| Back office or meeting room | 31 or 33 | Castor chair performance, indentation, joint tightness |
| Reception and main lobby | 33 | Wet slip result, wear layer, seam plan, matting |
| Open-plan office | 33 | Castor chair rating, indentation, cleaning regime |
| Retail sales floor | 33 or 34 | Wear layer thickness, colour through the wear layer, trolley loads |
| Restaurant dining area | 33 or 34 | Grease and stain resistance, wet slip result, chair drag |
| Commercial kitchen | 34 | Slip test to DIN 51130, drainage, coving, thermal movement |
| Stockroom or light assembly | 41 or 42 | Point loads, chemical resistance, joint strength |
The third column is what separates two quotes at the same class. For dining and kitchen areas, the slip requirement sits alongside the class, and the detail is in slip resistance ratings.
Lobby versus back office
A main lobby and a back office in the same building do not need the same floor. The lobby takes abrasive grit, water, trolleys, point loads and constant visual scrutiny. It usually justifies a higher class, a thicker wear layer, tighter seams and a properly sized entrance mat. The back office is dry, lightly trafficked and dominated by chair castors and desk legs, where indentation resistance matters more than abrasion. Splitting the schedule by zone usually costs less than buying lobby-grade product for the whole floor plate, and it puts the money where the traffic is.
Wear layer in mil: the number that separates vinyl products
A wear layer is the transparent top film that sits above the printed design or the backing. It is the part that takes the traffic, and its thickness is the most useful single number on a resilient datasheet. North American datasheets quote it in mil, one thousandth of an inch; European datasheets quote millimetres. One mil equals 0.0254 mm, so convert before comparing.
Common figures convert as follows: 6 mil is about 0.15 mm, 8 mil about 0.20 mm, 12 mil about 0.30 mm, 20 mil about 0.51 mm, and 28 mil about 0.71 mm.
Two cautions. Total thickness is not wear layer: a 5 mm plank with a 0.3 mm wear layer is unlikely to outlast a 2.5 mm plank with a 0.7 mm wear layer in abrasive traffic. And a thick wear layer does not fix a soft backing. Indentation comes from what is underneath as much as from what is on top.
Homogeneous vinyl takes a different approach: the colour runs through the thickness, so wear is less visible and the floor can be maintained for longer before replacement. That is a construction choice, not an AC class. Laminate does not use a mil wear layer figure; its overlay and EN 13329 class are the relevant numbers.
Writing the requirement into a tender
If the tender says heavy commercial vinyl, each supplier will interpret it differently and the prices will not be comparable. Write a line-item schedule that every bidder completes in the same format:
- Product type and construction, with the standard the class is declared against.
- ISO 10874 class for each area, not one class for the building.
- Minimum wear layer in millimetres for resilient floors; EN 13329 abrasion class for laminate.
- Slip test and test condition for each wet or contaminated area.
- Subfloor moisture and flatness limits, plus who prepares the substrate.
- Joint, seam, coving and transition details, including matting wells.
- Maintenance data and a cleaning regime at handover.
- Warranty terms with exclusions listed, not just the duration.
- Sample and batch reference for colour approval.
A supplier who cannot name the test behind a number cannot be compared with one who can. Reject any bid that answers a different question. The commercial flooring types guide helps match construction to zone before the numbers are fixed.
What to do next
- Split the floor plan into zones by traffic and contamination before choosing a product.
- Pull the current datasheets and check that every class names its standard; durability ratings explained covers the vocabulary.
- Convert wear layers to millimetres and compare like for like, not total thickness.
- Write the classes, wear layers and test methods into the enquiry, then ask suppliers to confirm them line by line.
- Plan the cleaning regime now, using the maintenance schedules templates, and hand it over with the floor.
- For kitchens and dining areas, read flooring for a restaurant kitchen before fixing the class.
For a second opinion on a schedule or a set of quotes, request a consultation and we will review the specification area by area.