Paints & Coatings

It is common knowledge by now that lead paint is a health hazard, especially for children.  Fewer people are aware that certain ingredients still found in paints today can pose health concerns, and fewer still know how to avoid these substances!

Architectural paints and coatings make up about half the total production of the United State’s coating industry, amounting to more than 650 million gallons in 2010!  Being conscientious about the ingredients in architectural coatings can go a long way toward reducing exposure to dangerous chemicals in paints.

No matter what paint or coating one chooses, it is wise to avoid buying large excesses, follow label instructions regarding ventilation, and dispose of old or unused products properly (for instance, at a Zero Waste Pittsburgh Household Hazardous Waste Collection event).

History

The first paints were natural pigment-based mixtures that got their colors from minerals, crushed beetles and berries, or more unusual sources such as a discharge from mollusks.  The first synthetic pigments and ready-mixed paints were created in the 1800s.  Additives were discovered that could improve colorfastness, application, and durability of paints and coatings.  Lead was one such additive, becoming widely used to speed drying, increase moisture resistance, and produce a desirable smooth, white finish.  Today many paints are mixed with the desired colorant at the point of purchase.

Types of Coatings

Coatings are decorative, functional, or both.  Functional coatings can, for example, enhance mold resistance, water repellence, and protection against wear.  Stains, finishes, sealants, varnishes, and paints are common coating types.

Green Paint (flickr: UnitedSoybeanBoard)

Green Paint (flickr: UnitedSoybeanBoard)

Most paints are composed of three main parts: a pigment/colorant, a binder to help paint apply and stick to a surface, and a solvent/carrier to keep the paint liquid.  Other compounds such as stabilizers, surfactants, and thickeners may also be added.  Once paint is applied, the solvent evaporates and leaves the solid components on the surface.  Solvents are the biggest contributor to the level of volatile organic compounds (VOCs) in paints.

VOCs are chemicals with high vapor pressures at room temperature, meaning they easily enter their gaseous form and dissipate into the surrounding air.  The smell associated with many paints is due to their VOC content.  Not all of them are harmful, but certain VOCs may contribute to headaches; dizziness; exacerbation of asthma; irritation of the eyes, nose and throat; and, if exposure is prolonged, organ damage or cancer.  VOCs also contribute to smog and ground-level ozone.

Luckily, there are many low- or no-VOC products on the market!  One option is natural coatings made from clay, lime, linseed oil, chalk, milk protein, plant or mineral dyes, natural latex, or any number of other natural materials.  Before buying, check to make sure these paints are composed of only non-toxic ingredients and that they do not contain essential oils that may aggravate chemical sensitivities.  Low-VOC manufactured paints and coatings are becoming more and more common as well.  Typically these coatings are water-based rather than containing organic solvents.  Definitions of no-VOC and low-VOC are not always consistent, but as a general rule no-VOC products have less than 5 g/L VOC content and low-VOC products should be below 50 to 150 g/L.  Varnishes and lacquers tend to have much higher VOC levels than paints.  Reported VOC levels do not necessarily include the VOCs from pigments, especially when products are colored at the point of purchase.  Other chemicals besides VOCs are also of concern, which is where certifications such as Green Seal are useful.

Green Seal Certification

Numerous paint and coating labels and certifications exist, but Green Seal is one of the best known and used.  The LEED credit for low-emitting paints and coatings uses Green Seal and SCAQMD standards.  Green Seal standards include performance criteria as well as restrictions on chemical content.  Three Green Seal standards apply to different categories of coatings:

  • GS-11 Paints and Coatings

“The standard includes wall, anti-corrosive, reflective coatings, floor paints, and primers and undercoats.”

GS-11 lays out criteria for flexibility, water resistance, colorfastness, adhesion, opacity, and other qualities of paints and specified coatings.  The standard prohibits the inclusion of carcinogens, mutagens, reproductive toxins, hazardous air pollutants, and ozone-depleting compounds, and requires that manufacturers provide appropriate end-of-life product instructions for consumers.

The VOC content limit is 50 g/L for flat topcoat paints and 100 g/L for other topcoats.  The highest limit in this category is 250 g/L for anti-corrosive coatings.  An additional 50 g/L is allotted for point-of-sale colorants.  Learn more here.

  • GS-43 Recycled Content Latex Paints

“The Green Seal standard for recycled content latex paint, GS-43, establishes environmental requirements for recycled-content, consolidated, and reprocessed interior and exterior latex paint.”

Floor varnish (flickr: Rubber Dragon)

Floor varnish (flickr: Rubber Dragon)

Learn more here.

  • GS-47 Stains and Finishes

“The GS-47 standard applies to stains and finishes that are intended and labeled for use on wood and metal surfaces: lacquers, shellacs, varnishes, sealers and stains (film-forming and penetrating).”

This standard includes criteria regarding dry time, adhesion, and UV resistance.  VOC limits vary from 120 g/L for low solids (up to 0.12 kg/L solids) coatings to 350 g/L for varnishes to 730 g/L for clear shellacs.  Learn more here.

Maintenance

Performance is important when considering how environmentally friendly a paint or coating is!  Long-lasting coatings mean that less maintenance is needed, producing lower overall VOC emissions over time.  Some coatings need numerous applications to achieve desired results and the number of coats also affects emissions.  Protective coatings help surfaces last longer, potentially reducing environmental impacts.  Typical latex paints may last three to seven years before a fresh coat is needed, whereas some high-performance reflective paints are less affected by heat and have much longer lifespans.  Take both performance and composition into consideration when choosing paints and coatings.

Advantages of Green Paints & Coatings

  • Lower VOC emissions and less ozone pollution
  • Low risk of health effects or chemical sensitivities
  • Improved indoor air quality
  • Excellent performance properties, such as UV resistance, durability, or flexibility
  • Potential LEED points

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