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Recycled denim reborn as sustainable insulation

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by Jessica Krippendorf last update:May 10, 2011

The world's most produced textile is making headway in the construction industry, as a green, clean and effective insulation product.
recycled denim used as insulation
recycled denim used as insulation

The world's most produced textile is making headway in the construction industry, as a green, clean and effective insulation product.

Old blue jeans are collected by textile recycling companies, which return the 100 per cent cotton material back to its loose fiber form and resell it to insulation manufacturers.

Arizona-based Bonded Logic is one of the first manufacturers of the product.

The material is chemically processed with a borate-based solution for fire, mold and insect-resistance. Borates are EPA-registered materials that have a lower toxicity level than table salt.

The treatment process, developed 30 to 40 years ago, is the same as that used to treat blown cellulose insulation made from paper, said Sean Desmond, sales and marketing manager for Bonded Logic.

The company’s UltraTouch Denim Insulation product can be used anywhere fiberglass batts can be used, including floors, walls, ceilings, crawlspaces and roofs. The only difference is that denim insulation is free of irritants and doesn’t require handlers to wear protective clothing.

Thicknesses range from a two-inch R-8 up to an eight-inch R-30.

It is sized to fit 16 and 24-inch wall assemblies, said Desmond.

“The batts are wider than fiberglass batts ensuring a ‘friction fit’ to give the cavity a nice seal,” he said.

The product is catching on in larger commercial and institutional projects in the U.S., mainly because the housing slump has made these types of projects the most available.

“The largest projects using this product would probably be domestic hospitals, which use upwards of a million square feet,” said Desmond.

“It is popular in health care settings because it has good sound control and because it is clean and safe.”

Acoustical performance tests indicate compliance with ASTM E90-02 and C423. The R-13 3.5-inch batts produce an NRC of 1.15, and an STC of 45.

Five-and-a-half-inch R19 batts produce the same NRC and an STC of 57.

It is made up of 90 per cent recycled content by weight. The remaining content is a binding agent.

“Essentially a non-woven textile has to have some kind of binding,” said Desmond.

“We use an olefin fiber as a binder, similar to rayon.”

A perforated version of the product is currently in production. In an eight-batt bag of R-13s meant for a 2x4 wall assembly, three pieces will come perforated with a variety of patterns to avoid having to cut the material with tools for off-sized cavities.

“There are several perforation patterns,” said Desmond, “So, you may end up with three-inch, two-inch, or eight-inch pieces. If you don’t need the perforations, you install the perforated batts as you would normal batts and the friction fit closes the holes.”

UltraTouch is distributed in Canada by Abbotsford-based Twin Maple Marketing. Owner Les Friesen said the product has been in the process of receiving Canadian Construction Materials Centre (CCMC) approval for the past four years.

The product is set to take off when the certification process wraps up sometime in the next 30 days, said Friesen.

“Architects are already specing it,” he said. “Achieving the (CCMC) number is basically all we need to get the product going into large projects.”

At present, it is mainly used in single and multi-unit housing developments across Canada.

“It already meets the National Building Code requirements – the number is a formality that we need to make this a big product for Canada,” he said.

The thermal performance evaluation results were unusual, but consistent with results of testing on other cotton cellulostic fibers: when the temperature dropped to 20 degrees F (about six degrees Celsius) the R-value increased slightly from an R-13 to an R-14.

“It is kind of a phenomenon with some insulating materials,” said Desmond.

“The R-values change because the fibers are cellulostic. Spray foams and fiber glass are different fibers and do not follow the same pattern.”

Friesen said that as the demand for green products has risen, so has the popularity of the insulation.

The product is VOC-free and doesn’t cause off-gassing. It is tested yearly for compliance with California 1350 – legislation for environmentally-friendly materials and indoor air quality.

Projects that use denim insulation can be eligible for up to 12 LEED credits in the categories of recycled content, construction waste management, rapidly renewable material, innovation in design, indoor air quality and low-emitting materials.

Friesen said that reducing energy use isn’t the only function of a green product.

“Green is also when you save product from going into the landfill,” he said.

“This product is 90 per cent recycled and 100 per cent recyclable. “

last update:May 10, 2011

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