Bio-based upholstery fabric: the content is usually in the coating

Bio-based content on a seat is measured the same way it is measured on a wall: as a percentage of new organic carbon against total organic carbon, tested by radiocarbon analysis. What changes is where in the material that carbon sits.

On a woven wallcovering the bio-based part is usually the fibre. On upholstery it is more often the coating. Most bio-based upholstery is a coated textile, which is a backing cloth, a polymer layer over it and a topcoat. The renewable feedstock replaces the fossil feedstock inside that polymer, so the part of the material carrying the environmental claim is also the part taking the wear.

Which is why the percentages sit so far apart. A coated upholstery built on a bio-polyurethane can be around a tenth bio-based by carbon. One built to replace almost everything in the formulation, plasticisers and backing included, reaches four fifths or more. A woven fibre drawn from plant-derived polyethylene spans a wide band depending on construction and at the top of it reaches nine tenths. All of them are accurately described as bio-based.

None of those numbers say anything about how the fabric performs. Abrasion resistance, cleanability, fluid barrier and fire rating are separate properties with separate tests, and a high bio-based percentage predicts none of them. A seat is cleaned more often and more harshly than a wall, so on upholstery the distinction matters more than it does anywhere else in a building.

The backing is worth asking about on its own. It is structural, it is often where the moisture barrier lives, and it is not always made from the same material as the face. Organic cotton, recycled polyester and a dedicated fluid barrier are all in use, and each one changes what the finished cloth will do.

So there are three questions and they go in order. What is the verified percentage? What is the backing? And what does the cloth do under the tests the project actually specifies?