Guide · For the trade
TARR rating and the other carpet wear ratings: what the number means and which one the job needs
A TARR rating, the Texture Appearance Retention Rating, is the Carpet and Rug Institute's commercial wear rating: a carpet sample is run under a hexapod drum (ASTM D5252) or a Vettermann drum (ASTM D5417), then graded against the CRI reference scale (ASTM D7330) from 5 to 1, where 5 is no change. The result is reported as a class: Moderate at 2.5 to 2.9, Heavy at 3.0 to 3.4, Severe at 3.5 and above. A corridor, a lobby or an open office needs Heavy or Severe; a private office or guestroom is fine at Moderate. Residential carpet uses the same scale as the appearance retention rating and European wool mills use a use class instead.
This guide is for the designer or junior who sees "TARR: Severe" on one sheet, "ARR 3.0" on another and "Heavy Contract" on a third and needs to compare them. It covers how the test works, what the classes mean, the residential and European equivalents, where TARR stops being useful and how to match a rating to a room. The numbers behind the rating are in the carpet density and carpet face weight guides.
How the TARR test works
Wear in a carpet is mostly appearance change, not fiber loss: the pile loses its twist, mats in the traffic lane and stops reflecting light the way the rest of the room does. The TARR test reproduces that. A sample is fixed inside a rotating drum and a weighted steel hexapod (a six-footed tumbler with rubber-tipped studs) rolls over it for a set number of cycles, flexing and crushing the pile the way thousands of footsteps do; the Vettermann drum does the same with a steel ball. The sample is then vacuumed and graded against references of the same construction. A 5 looks new; a 1 is matted flat. The grade after the long-cycle run is the TARR, reported as the class it falls into.
Carpet wear rating classes in one table
| Rating | Grade on the CRI scale | Specify it for |
|---|---|---|
| TARR Severe | 3.5 or higher | Corridors, lobbies, elevator landings, open-plan offices, retail, schools, anywhere with rolling loads |
| TARR Heavy | 3.0 to 3.4 | Conference rooms, mid-market hotel corridors, restaurants, multifamily common halls |
| TARR Moderate | 2.5 to 2.9 | Private offices, guestrooms, executive suites, boardrooms |
| Residential ARR 3.0 or more | Same scale, shorter test | Halls, stairs, family rooms, any room with a dog |
| Residential ARR 2.5 to 2.9 | Same scale, shorter test | Bedrooms, formal living rooms, light traffic |
| EN 1307 class 22 or 23 | Use class, not a drum grade | General and heavy domestic; class 23 for halls and stairs |
| EN 1307 class 32 or 33 | Use class, not a drum grade | General and heavy contract; class 33 for corridors and public rooms |
The classes line up roughly: a TARR Severe nylon and an EN 1307 class 33 wool are both corridor carpets and a residential ARR 2.5 and a class 22 are both bedroom carpets. They are not the same test and a European mill will not hand you a TARR for a wool Wilton; the drum test was written around tufted nylon.
Carpet durability rating by fiber and construction
TARR rewards dense, low, tightly twisted pile in a resilient fiber. Solution-dyed nylon 6,6 in a 1/8 to 1/4 inch loop or a dense cut pile is the construction most commercial Severe ratings sit on; carpet tile is almost always Severe by construction. Polyester and polypropylene rate lower at the same weight because the fibers do not spring back; triexta sits between. Wool is resilient by nature and a dense wool Wilton or Axminster at 40 oz or more outlasts most nylon in a corridor, but it is usually rated by use class rather than a drum grade. Stanton rates its wool and wool-blend styles from residential to light, medium or heavy commercial; BIC uses light, moderate and general commercial; DMI's performance lines carry Heavy Domestic and Heavy Contract use classes.
Where the TARR rating stops being useful
Three places. First, stairs: the drum does not bend pile over a nosing, so a Severe carpet still wears at the stair edge faster than anywhere else, which is why stair warranties are shorter. Second, color: a Severe rating measures texture, not how a solid light color shows soil, so a Severe pale cut pile in a lobby will look tired before it mats; pattern and mid-tones carry the rating further. Third, rugs: TARR is a broadloom and tile rating and finished rugs are rated by the mill's traffic recommendation (most rug mills print light, moderate or heavy foot traffic on the sheet). For a rug in a hall or entry, knot or tuft density and a low pile are the rating.
Matching a carpet traffic rating to the room
- Name the traffic honestly: people per day, carts, casters, pets and whether the room is a path or a destination.
- Pick the class: Severe for paths and public rooms, Heavy for shared rooms, Moderate for private ones; residential ARR 3.0 for halls and stairs, 2.5 for bedrooms; EN class 33 or 23 for the same paths in a European wool.
- Check the construction behind the rating: pile height 1/4 inch or less and a density over 5,000 for Severe; a dense pad or direct glue so the pad does not undo the carpet.
- Read the warranty against the rating: most commercial texture retention warranties are written as "will not fall below 3.0 for 10 years", and the number should match the class.
- Specify the maintenance: a Severe carpet without entrance matting and an extraction schedule performs as Moderate.
Questions designers ask
What grade of carpet should a client buy for a given room?
For commercial paths and public rooms, TARR Severe; for shared commercial rooms, Heavy; for private offices and guestrooms, Moderate. In a residence, ARR 3.0 or more for halls, stairs and family rooms, 2.5 or more for bedrooms. Where the mill rates by use class, heavy commercial or EN 1307 class 23 and 33 for the hard-working rooms.
Is wall-to-wall carpet still specified in 2026?
Yes, for reasons that have not changed: acoustics, warmth, slip resistance and cost per square foot. Where it has retreated, open-plan offices and some hospitality lobbies, carpet tile and area rugs took its place and both are rated on the same scale. Bedrooms, stairs, corridors and senior living remain broadloom territory.
What should a designer avoid when reading a carpet wear rating?
Reading face weight as a wear rating, assuming a lifetime wear warranty means a high TARR (wear warranties cover fiber loss, TARR covers appearance), comparing a drum grade with a European use class as one scale and specifying a Severe carpet over a soft residential pad. The carpet warranties guide covers the first two.
What is a tog rating and is it a wear rating?
No. Tog is a measure of thermal insulation used in the UK and Europe for underlay and carpet over underfloor heating: a lower tog lets more heat through and carpet and pad over radiant heat should total about 2.5 tog or less. It says nothing about durability.
Do hand-knotted rugs have a TARR rating?
No. The drum test is for broadloom and carpet tile. A hand-knotted wool rug's durability is its knot density, its pile height and the wool itself; a dense, low-pile hand-knotted rug in a hall outlasts most rated broadloom.
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