425-373-1987
follow us:

The Anatomy of a Sofa

Just as we consider the health impact of the food ingredients we eat, it makes sense to ask what effect the ingredients of the furniture in our homes have on our personal and planetary well being. Yet finding accurate data about the parts and pieces that compose our furniture, carpets, and window treatments can be a challenge. Most furniture manufacturers consider this proprietary information and rarely disclose it to the public. The conscious consumer needs to ask what materials are used and where they came from, with the understanding that they are free to take their money elsewhere without satisfactory answers to these questions.

Our homes are furnished with things that come from a variety of materials, including fabrics, metals, wood, plastics, coatings. All of these materials affect the Indoor Air Quality of our home. Each of these ‘ingredients' are industrial products. For example, a sofa has:

  1. Fabric (natural from plants and animals or synthetic from chemical processes), or Leather (from animals and dyes from the chemical industry)
  2. Fill, which is foam or fiber (all chemically based materials whether natural or synthetic)
  3. Wood (sustainable, fair trade, or not) or metal (from mining) which is stained and coated (from the chemical industry)
  4. Coatings on fabrics for stain resistance and fire-retardancy (from the chemical industry).

All upholstered furniture has these essential components which are constructed with craftsman's techniques using quality ‘ingredients'. The following discusses the health affects of the ingredients in upholstered furniture, so that you can make a more informed choice the next time you shop.

Fabrics and Leathers

Fabrics create the outer casing, which forms the ‘skin' over the sofa. The aesthetic quality includes how it feels, how it looks, even how it smells. Fabric's structural quality includes the fiber content, the tightness of weave, the seaming threads and stitching style. Many durable synthetic fabrics are now made of recycled and/or recyclable materials. Synthetics are good for low allergen and easy-maintenance features. Although some synthetics, vinyl and leathers can be selected which have low-emitting VOC's1 as rated by GreenguardTM2, this doesn't guarantee an environmentally friendly production method. However, leather tanneries are improving their environmental impacts by reducing the use of heavy metals in their dyes, and by using polyurethane's which have few or no solvents, yet are colorful.

Natural materials have the inherent fiber qualities that are both beautiful and durable, yet the dyes/treatments used to increase stain resistance or reduce mold susceptibility can be an irritant to some people. Organic natural fibers (cotton, hemp, sisal, etc,) have no pesticide residue to provoke sensitivities. Cotton is less expensive than wool and takes dyes well but wrinkles and stains easily, supports mold growth and is flammable. It is more durable when tightly woven and blended with tough synthetics and requires chemical treatment for stain and fire resistance. Wool is very durable, naturally fire-resistant and takes dyes very well but some people are allergic to it. Some fabrics are manufactured in a sustainable process, using only 16 out of 1600 commercial dyes to protect the environment yet they come in hundreds of colors and patterns and have a healthy effect on the home. These fabrics, made of natural fibers or recyclable, recycled and biodegradable fibers, are inherently flame-resistant.

The Fill

Under the fabric layer of upholstered furniture, is the ‘fill,' composed of loose batting, over the structural form of the cushion. The loose fill is commonly made of non-recyclable polyester batting, but can be made of down and feathers, sustainable wool or organic cotton, preferably seedless cotton. The molded inner cushion is commonly
made of polyurethane foam that comes in several grades of density, firmness and compression strength. Very low emitting foams without CFC's3 are widely available from companies who are members of the Polyurethane Foam Association4. However, these are still not biodegradable. When selecting seating foams, choose high-resiliency, high-density foam so it will keep its shape longer, yet is comfortable. An eco-friendly alternative is 100% pure rubber latex, but it is not naturally flame-retardant. Latex foam rubber can be natural or synthetic, and has superior cushioning performance - at a premium price. It is better tolerated than foam by those chemically sensitive to the minimal out-gassing of foam, however, some people develop allergies to natural latex if under constant direct contact with it.

Annually, 79% of the civilian fire deaths in America occur in private residences, most often started in a piece of furniture. Flame-retardant additives used today present no more off-gas potential than virgin foam, but flame retardants are not environmentally friendly. Research continues into this area of life-safety standards balanced against environmental impacts. A new alternative is the use of fire-barrier fabrics developed initially for the commercial mattress industry but now available to the residential furnishings trade.

The stronger the cushion construction, the longer lasting the furniture will be. The seat cushion fill can also be made of ‘8-way hand tied' springs, or ‘marshal' springs encased in honey-comb style resilient wrap. The manufacturers have multiple choices of gauge of metals used in springs, tightness of coiling, and plastic vs. metal clip attachments. Back cushions are generally made of batting, occasionally wrapped around foam.

The Frame

The frame is the structural skeleton of the upholstered piece. It can be made of metal, molded plastics or wood. Wood is the most common framing material for upholstered furniture. Kiln-dried hard woods are sturdier providing the joints are reinforced with glue on the blocks, dowels or mortise & tendon joints. Some manufacturers disclose that they use FSC (Forest Stewardship Council5) certified wood yet others are smaller, family-owned companies which own their own forests and have practiced stewardship voluntarily for years. Some manufacturers use plywood or particleboard that may out-gas. The hidden wooden structure is not sealed or finished in portions that are covered, therefore, look to the manufacturers' literature for the Hardwood Plywood Manufacturers Association (HPMA) HUD6 emission standards stamped on the composite woods they use for the structure. Exposed portions of wood should be thoroughly sealed with paints, stains and topcoat finishes that are non-toxic low VOC emitting compounds.

Inside the base of the frame, an eight-way hand tied construction is generally considered superior. If it is made with a weak gauge metal in a loose coil, fastened with plastic clips, its durability is compromised. Sinuous springs or rubber webbing are an alternative method to make a resilient surface for the seat cushions to rest on. These come in a variety of gauges and strengths, and have a neutral health affect.

When selecting a piece of furniture, be consistent in quality level of all materials and construction. That is, a well made structure with good cushions should be covered with beautiful yet heavy duty fabric. A less expensive piece made with a molded or plywood frame can have less expensive, yet still durable, fabric. Occasional pieces that do not get much use can be covered in more delicate fabrics such as silks and lightweight cottons or chenille.

The materials from which our furniture is made affect us in ways both obvious and subtle. Aside from visual appeal of the piece in our home, how does it smell when we have all natural materials, low VOC synthetic or natural materials, and good ventilation? How does the fabric feel on our bare feet, on our skin resting on the arm of the sofa? How does the room sound when we fill it with all hard surfaces (the kitchen & bath...) or with mostly soft surfaces (the bedroom)? A healthy, easy-maintenance environment can have a variety of looks and need not be predictable or dull. It can be attractive, reflecting your individual taste, yet still be healthy for you and the environment.

Article copyrighted by Michelle Molloy, ASID of PenatesTM Interior Design 206-522-7784, www.penatesdesign.com

Resources

  • Polyurethane Foam Association www.pfa.org http://www.safesleep.org/pdf/ september2002.pdf
  • The Green Guide www.thegreenguide.com
  • McDonough Braungart Design Chemisty. LLC www.mbdc.com
  • GREENGUARD www.greenguard.org
  • Indoor Air Quality Certified http://www.nfpa.org/Research/ NFPAFactSheets/ FireUSAndCanada/ fireusandcanada.asp

1. VOC; unhealthy volatile organic compounds which evaporate out of the materials into the air.
2. www.greenguard.org The GREENGUARD Environmental Institute governs the GREENGUARD Certification Program and provides the world's only guide to third-party certified
low emitting interior products and building materials.
3. CFC's chlorofluorocarbons have been eliminated from the manufacturing process by companies who are members of the Polyurethane Foam Association
4. The mission of the Polyurethane Foam Association (PFA) is to educate customers and other
groups about flexible polyurethane foam and to promote its use in manufactured and industrial products.
5. The Forest Stewardship Council was created to change the dialogue about and the practice of sustainable forestry worldwide. The FSC standards represent the world's strongest system for guiding forest management toward sustainable outcomes.
6. HUD Housing & Urban Development standard assures you that it will have lower than 0.2 ppm formaldehyde emissions.