The questions is whether it’s a better choice to use inherently flame retardant fabrics such as AvoraFR rather than a natural fiber (like cotton) which has been doused with toxic FR chemicals. The answer is complicated and like most in this emerging green area, there may be no “best” answer. We think the answers may lie in the tradeoffs we have to make. But we’ve got an opinion, and it’s based on the following reasoning:
Fabrics which are inherently flame retardant are synthetics which have been changed at the molecular level to make the fabrics thermally stable and able to pass commercial flame tests. Some petroleum-based synthetic fibers, such as Avora FR, Trevira CS and Lenzing FR viscose – add a flame retardant to the chemical treatment before polymer extrusion rather than change the molecular structure of the polymer. This process builds the chemical treatment into the backbone of the polyester rather than adding it later to the finished product. It is presumed to be less likely to expose the occupants to chemicals.
So how do you compare the two?
When comparing the synthetic with a natural fiber, we think it’s important to look at the carbon footprint of the fibers. A synthetic like polyester requires much more energy to produce a ton of fiber than does conventional cotton – in megajoules (MJ) of energy the difference is about four times: 126,000 MJ polyester vs. 33,000 MJ for conventional cotton. Organic cotton is even less: only 16,000MJ.
It’s important to look at how these fibers are woven into fabric. (And that’s a different set of carbon calculations). If the polyester or the cotton is produced conventionally, the finished fabric has residuals of many chemicals which have been proven to harm human health. The majority of Americans mistakenly believes that the government tests chemicals used in consumer products to ensure safety, accoring to an opinion poll released by the Washington Toxics Coalition. However, under the Toxic Substances Control Act (TSCA), there is no legal requirements to test most chemicals for health effects, including impacts on neurological development, at any stage of production, marketing and use. An organic fabric is one which has not used any of the many chemicals used in textile production which are known to be toxic.
So looking at two fabrics (even if one polyester fabric is produced using optimized production methods – i.e., avoiding the toxic chemicals) the organic cotton (or better yet, hemp or linen) fabric is one I’d rather live with. But fire kills many people every year and we have reason to keep fire codes in place in public spaces. So the issue focuses on the chemistry used to fire retard the fabrics.
Natural fibers must have a topical FR treatment applied after manufacture. In the past, these treatments were based on halogenated chemistry, like PBDEs. The industry is moving away from these chemicals and most have been banned, but decaBDE is still allowed in the US. With careful attention and questioning of your supplier, you can have a natural fiber fabric that has an FR treatment which meets all codes – and which is not persisten, bioaccumulative and compromises your health.
So now the question becomes how dothe two fibers react in actual fires?
An important thing to remember about synthetics is that they do not burn, they melt. That’s why protective clothing (firemen, police, rescue) is not made of synthetics – even inherently fire retardant synthetics – because the melting fabric would cause severe burns.
Another issue (and one we think is most important) is that the smoke created by burning or melting fabrics. Conventionally produced fabrics (natural fiber or synthetic) release chemicals which add an extra dimension to the already toxic smoke.
So where do we stand?
- With a carbon footprint of 16,000 MJ vs 126,000 MJ (organic cotton vs. polyester) to make the fiber and
- with organic fabrics having little or none of the chemicals which have been proven to harm human health and
- because of the ability to use a nonhalogenated FR treatment on an organic fabric and
- in the case of a fire, not having to breathe toxic fumes from melting synthetics or conventionally produced fabrics
is there really a choice?