Should I choose a hemp or linen fabric?

5 08 2015

We are often asked for 100% hemp fabric in lieu of linen fabrics. We offer hemp and adore it, but it may not be the best eco choice.  Make no mistake – we love hemp, we sell hemp fabrics and we think the re-introduction of hemp as a crop would be a boon for American farmers and consumers.

But hemp that is used to produce hemp fabric via conventional methods – as opposed to GOTS methods – is an inferior choice to any GOTS certified fabric. So the overriding difference is not between hemp and any other fiber, but between a GOTS certified fabric versus one that is not GOTS certified, because GOTS certification assures us that the fabric is free of any chemicals that can change your DNA, give you cancer or another dread disease or affect you in other ways ranging from subtle to profound. It also assures us that the mill which produced the fabric has water treatment in place, so these chemicals don’t pollute our groundwater – and that the mill pays fair wages to their workers who toil in safe conditions!

The GOTS certification requires that the fiber used in the fabric be third party certified organic. Organic linen is more available and less expensive then organic hemp, so we often use linen instead of hemp in our fabrics. Using organic linen instead of organic hemp keeps the price lower for you and you do not give up any performance characteristics at all.   Allow me to say that once more: You do not give up any performance at all.

To begin with, do not be confused by the difference between the fiber and the cloth woven from that fiber – because the spinning of the yarn and the weaving of the cloth introduces many variables that have nothing to do with the fibers. Both hemp and flax (from which linen is derived) are made from fibers found in the stems of plants, and both are very laborious to produce. The strength and quality of both fibers are highly dependent on seed variety, the conditions during growth, time of harvest and manner of retting and other post-harvest handling.

Yarns, made from the fibers, are graded from ‘A’, the best quality, to below ‘D’ and the number of twists per unit length is often (but not always) an indication of a stronger yarn.   In addition, the yarns can be single or plied – a plied yarn is combined with more than one strand of yarn. Next, the cloth can be woven from grade ‘A’ yarns with double twist per unit length and double ply into a fabric where the yarns are tightly woven together from cloth that is lightweight or heavier, producing a superior fabric.  Or not.

Now let’s look at some of the differences between hemp and linen:

Hemp and linen fibers are basically interchangeable – there is very little to distinguish flax fibers from hemp fibers.  In fact,  hemp’s fibers so closely resemble flax that a high-power microscope is needed to tell the difference. Without microscopic or chemical examination, the fibers can only be distinguished by the direction in which they twist upon wetting: hemp will rotate counterclockwise; flax, clockwise.  And in general, they tend to have the same properties.

In general, there are many similarities between cloth made from hemp and cloth made from linen:

  • Both linen and hemp become soft and supple through handling, gaining elegance and creating a fluid drape.
  • Both hemp and linen are strong fibers – though most sources say hemp is stronger (by up to 8 times) than linen (even though the real winner is spider silk), but this point becomes moot due to the variables involved in spinning the fiber into yarn and then weaving into fabric.   The lifespan of hemp is the longest of all the natural fibers.
  • Both hemp and linen wrinkle easily.
  • Both hemp and linen absorb moisture. Hemp’s moisture retention is a bit more (12%) than linen’s (10 – 12%)
  • Both hemp and linen breathe.
  • Both hemp and linen are natural insulators: both have hollow fibers which means they’re cool in summer and warm in winter.
  • Both hemp and linen have anti-bacterial properties.
  • Both hemp and linen benefit from washing, becoming softer and more lustrous with each wash.
  • Both hemp and linen are resistant to moths and other insects.
  • Both hemp and linen absorb dyestuffs readily.
  • Both hemp and linen biodegrade.

In general, hemp fiber bundles are longer than those of flax.   So the first point of differentiation is this: the length of the fibers. Hemp fibers vary from 4 to about 7 feet in length, while linen is general 1.5 to 3 feet in length. Other differences:

  • The color of flax fibers is described as yellowish-buff to gray, and hemp as yellowish-gray to dark brown.
  • Hemp is highly resistant to rotting, mildew, mold and salt water.
  • Hemp is also highly resistant to ultraviolet light, so it won’t fade or disintegrate in sunlight.
  • Hemp’s elastic recovery is very poor and less than linen; it stretches less than any other natural fiber.

The biggest difference between hemp and linen might be in the agricultural arena: Hemp grows well without the use of chemicals because it has few serious pest problems, although the degree of immunity to attacking organisms has been greatly exaggerated.  Several insects and fungi specialize exclusively in hemp!  But despite this, the use of pesticides and fungicides are usually unnecessary to get a good yield. Hemp has a fiber yield that averages between 485 – 809 lbs., compared to flax, which averages just 323 – 465 lbs. on the same amount of land.  This yield translates into a high biomass, which can be converted into fuel in the form of clean-burning alcohol.

Farmers claim that hemp is a great rotation crop – it was sometimes grown the year prior to a flax crop because it left the land free of weeds and in good condition.   Hemp, it was said, is good for the soil, aerating and building topsoil. Hemp’s long taproot descends for three feet or more, and these roots anchor and protect the soil from runoff. Moreover, hemp does not exhaust the soil. Additionally, hemp can be grown for many seasons successively without impacting the soil negatively. In fact, this is done sometimes to improve soil tilth and clean the land of weeds.

The price of hemp in the market is far higher than for linen, despite hemp’s yields.   We have no idea why this is so.

The overriding difference is not between hemp and linen, but between a hemp OR linen fabric that has a GOTS certification and one that does not. That means that a conventional hemp fabric, which enjoys all the benefits of hemp’s attributes, also introduces unwanted chemicals into your life: such as formaldehyde, phthalates, heavy metals, endocrine disruptors and perhaps soil or fire retardants.   The GOTS certified fabric is the better choice. If the choice is between a conventional hemp fabric and a GOTS certified linen fabric, we wouldn’t hesitate a second to choose the linen over the hemp, especially because hemp and linen are such close cousins.

 

 

 

 

 

 

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What is the energy profile of the textile industry?

16 06 2009

carbon_footprint

If you’ve been following along you’ll know we haven’t even reached the point where we begin weaving – everything up till now dealt only with producing the raw materials (the fiber) and spinning into yarn!

So, the yarns are at the mill.  And that’s the kicker: we’ve been talking about how much energy it takes to produce the various fibers – and it varies dramatically – but there is no dramatic difference in the amount of energy needed to weave fibers into fabric depending on fiber type.[1] The processing is generally the same whether the fiber is nylon, cotton, hemp, wool or polyester:

  • thermal energy required per meter of cloth is 4,500-5,500 Kcal and
  • electrical energy required per meter of cloth is 0.45-0.55 kwh. [2]

This translates into huge quantities of fossil fuels  –  both to create energy directly needed to power the mills, produce heat and steam, and power air conditioners, as well as indirectly to create the many chemicals used in production.  In addition, the textile industry has one of the lowest efficiencies in energy utilization because it is largely antiquated.

So let’s go with the energy used to produce one KG of fabric (which is 92 MJ per KG as the New Zeland Merino Wool LCA study found).   Keeping  the energy needed for production as a  constant the synthetic fabrics still top the list:

Embodied Energy in production of various fibers + processing:
energy use in MJ per KG of fiber: energy use in MJ per KG of fabric TOTAL energy use in MJ per KG of fabric to produce fiber + weave into cloth
flax 10 92 102
Cotton, convt’l. 55 92 147
wool 63 92 155
Viscose 100 92 192
Polypropylene 115 92 207
Polyester 125 92 217
acrylic 175 92 267
Nylon 250 92 342

 

That means that it takes 3,886 MJ of energy to produce 25 yards of nylon fabric, which is  about enough to cover one average sofa.  That compares to 1,158 MJ if the fiber you used was flax (linen).  To put that into perspective, 1 gallon of gasoline equals 131 MJ of energy; driving a Lamborghini from New York to Washington D.C. uses approximately 2266 MJ of energy.(4)

Textile_total_energy_input

In addition to the energy requirements for textile production,  there is an additional dimension to consider during processing:  environmental pollution.  Conventional textile processing is highly polluting:

  • Up to 2000 chemicals are used in textile processing, many of them known to be harmful to human (and animal) health.   Some of these chemicals evaporate, some are dissolved in treatment water which is discharged to our environment, and some are residual in the fabric, to be brought into our homes (where, with use, tiny bits abrade and you ingest or otherwise breathe them in).  A whole list of the most commonly used chemicals in fabric production are linked to human health problems that vary from annoying to profound.  And new research is linking many diseases and disorders to exposure to chemicals.  Through the new science of environmental health science, we are learning that exposure to toxic chemicals (at levels once thought to have been safe) is increasing the  chronic disease burden for millions of us.  For more information about this disturbing concept,  check out the National Institute of Environmental Health Sciences, part of the National Institutes of Health.
  • The application of these chemicals uses lots  of water. In fact, the textile industry is the #1 industrial polluter of fresh water on the planet.[3] These wastewaters are discharged (largely untreated) into our groundwater with a high pH and temperature as well as chemical load.  I wrote about a documentary which catalogues the ravages brought on by water pollution and how it impacts those downstream, called (interestingly enough), DOWNSTREAM.

We are all downstream.


[1] 24thsession of the FAO Committee on Commodity Problems IGG on Hard Fibers of the United Nations

[2] “Improving profits with energy-efficiency enhancements”, December 2008,  Journal for Asia on Textile and Apparel,  http://textile.2456.com/eng/epub/n_details.asp?epubiid=4&id=3296

[3] Cooper, Peter, “Clearer Communication,” Ecotextile News, May 2007.

(4)  from Annika Carlsson-Kanyama and Mireille Faist, 2001, Stockholm University Dept of Systems Ecology, htp://organic.kysu.edu/EnergySmartFood(2009).pdf

Embodied Energy in production of various fibers + processing:
beach image energy use in MJ per KG of fiber: energy use in MJ per KG of fabric TOTAL energy use in MJ per KG of fabric to produce fiber + weave into cloth
flax 10 92 102
Cotton, convt’l. 55 92 147
wool 63 92 155
Viscose 100 92 192
Polypropylene 115 92 207
Polyester 125 92 217
acrylic 175 92 267
Nylon 250 92 342