Formaldehyde Emissions and Particleboard Core Products

Formaldehyde Emissions and Particleboard Core Products
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Formaldehyde Emissions and Particleboard Core Products

Topic

Like many technical issues, the topic of formaldehyde emissions is often misunderstood. At times requests are made for formaldehyde-free products. While these materials are available, at a much higher cost, the facts indicate they are generally not necessary.

The information contained in the paper has been summarized from the following sources:
# Formaldehyde Emission Barriers for Particleboard and MDF

Composite Panel Association
www.pbmdf.com

# An Update on Formaldehyde, 1997 Revision

U.S. Consumer Product Safety Commission
www.cpsc.gov
Formaldehyde Defined

Formaldehyde is one of the most widespread chemicals in the world. It is used in consumer products, such as shampoo, lipstick, toothpaste, vaccines, disinfectants, permanent press clothing, upholstery, liquid coatings, particleboard (PB) and medium density fiberboard (MDF).

It is a simple compound made of carbon, hydrogen and oxygen, and is a colorless, strong-smelling gas. It is one of the large family of chemical compounds called volatile organic compounds (VOCs). The use of the word 'volatile' means that the compounds vaporize, that is, become a gas, at normal room temperatures.

Formaldehyde is naturally produced in plants and animals. It is important in the human metabolic process. It is a by-product of combustion in burning wood, kerosene, natural gas, automobile engines and cigarettes. Formaldehyde can also off-gas from materials made with it.

Issues

Formaldehyde has become a concern because in high levels (above 0.1 parts per million of air) it can cause watery eyes, burning sensations in the eyes, nose and throat, nausea, coughing, chest tightness, wheezing, skin rashes, and allergic reactions.

Some persons have developed allergic reactions, asthmatic reactions and skin rashes from skin contact with solutions of formaldehyde or durable-press clothing containing formaldehyde.

At very high levels it has been observed to cause cancer in scientific studies using laboratory animals and may cause cancer in humans.Typical exposures to humans are much lower and the risk of causing cancer is believed to be small.

Formaldehyde is just one of several gases present indoors that may cause illnesses. Many of these gases, as well as colds and flu, cause similar symptoms.

Formaldehyde in particleboard

Urea formaldehyde adhesives are used in most PB/MDF products worldwide. It enables the adhesive to bond the wood particles and fibers together. These adhesives are easy to work with, strong, durable and cost-effective.

Changes in resin technology and improved manufacturing controls have dramatically reduced formaldehyde emissions in particleboard, as much as 80-90% since the early 1980's. Product standards (ANSI A208.1 for particleboard) contain formaldehyde emissions limits at levels lower than those common in the past.

ANSI requirements

ANSI A208.1 states formaldehyde shall not exceed 0.3 parts per million (ppm) under test conditions. Test conditions include an air exchange rate of 0.5/hour and test temperatures of 77o +/- 2oF. Board sheets meet or exceed this requirement when manufactured.

Risk

Formaldehyde is normally present at levels less than 0.03 parts per million (ppm) in both outdoor and indoor air. Rural areas have lower concentrations than urban areas. Indoor levels can increase with the presence of products that may add formaldehyde to the air.

Many factors affect the levels of formaldehyde found in indoor air. These factors include:
# What is releasing the formaldehyde (the source).

o Bare materials, such as particleboard flooring underlayment, have greater emissions than sealed/finished materials.

# Temperature

o Higher temperatures release more formaldehyde, lower temperatures release less.

# Humidity

o Higher humidity releases more formaldehyde, lower humidity releases less.

# Season and time of day.

o Hot, humid days have higher levels of formaldehyde.

o Cool, dry days or nights have lower levels.

# Air exchange rate.

o Increased home/office sealing and insulation increases formaldehyde levels.

o Low air change levels trap emissions in a room. High changes dilute emissions.

o Rooms typically are designed to have at least 8-12 air changes per hour.

The last 20 years have seen great efforts to reduce formaldehyde emissions in manufactured products. Pressed wood products such as particleboard have had reductions of 80-90%.

For most people, low-level exposure to formaldehyde (up to 0.1 ppm) does not produce symptoms.

Risk reduction - general

To reduce exposure:

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Wash durable-press fabrics before use.

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Avoid the use of foamed-in-place insulation containing formaldehyde.

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Use panel products not made with urea-formaldehyde glues.

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Use particleboard panel products conforming to ANSI A208.1-1993.

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Ensure cabinets made with particleboard contain a high percentage of panel surface and edges that are laminated or coated.

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Ensure an adequate number of air exchanges are designed into the workplace.

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Keep temperatures cooler. Test conditions are 77oF +/- 2o.

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Keep humidity low.

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Eliminate plants from the workplace.

Risk reduction - particleboard

Particleboard is an ideal component for many products because it is dimensionally stable, has tight thickness tolerances and has a flat, smooth surface. Most often the board is used as a substrate for laminates, overlays and finishes. While these surface treatments are aesthetic; they also protect the substrate against water damage, stains and damage from normal use. These same treatments also serve as barriers, reducing formaldehyde emissions from the PB core.

Aging

Emission levels are always highest immediately after manufacturing of the board and quickly drop as the board ages. Average emission levels from unfinished boards can drop by about 25% after the first month, and are usually half the initial amount in about six months or less.

This often reflects the time the raw board is in storage at the manufacturer, in transit to the distributor, in storage at the distributor, in transit to the customer-manufacturer and in storage at the customer-manufacturer before being used in manufacturing the final customer product.

Within a year levels have decayed to approximate equilibrium with background ambient levels.

Barriers

Effective barriers can reduce emission levels by 95% or more. Good barrier properties include a continuous laminate or coating. Laminates generally require good adhesion to the board.

Case Systems recommends and uses PVA formaldehyde-free rigid adhesives. Independent tests indicate, when properly applied, PVA's are 2-1/2 times stronger than water- or solvent-based contact adhesives. With contact adhesives, adhesion failure is evidenced by delamination; with PVA's failure is evidenced not by delamination but by failure of the particleboard substrate.

Coatings properly applied in multiple layers of adequate thickness can ensure good barriers. Considerations include:

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Oil-based finishes are better than water-based or latex.

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Pinholes and other imperfections decrease the effectiveness of the coating.

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Wood veneers are less effective depending on the species and thickness. Oak is more porous than maple. Surface veneers are thinner than core veneers.

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Some finishes may contain formaldehyde and be a potential emission source.

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Water-based finishes may lose their integrity as a barrier when humidity reaches levels high enough to cause swelling in wood substrates.

Laminates are almost impermeable to emissions.

The following materials common in casework are listed in their generally recognized order of effectiveness as barriers. (Effectiveness may vary due to application and environmental factors.)

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High pressure laminates

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Cabinet liners (20 mils+)

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Melamine; thermofused more effective than foil.

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Polyurethanes

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Epoxy sealers/paints

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Oil or lacquer sealer plus varnish or lacquer top coat

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Finished wood veneers

CALCULATION OF EMISSIONS IN PARTICLEBOARD-BASED PRODUCTS

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Manufactured board maximum emission level 0.3000 ppm

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First month aging effect - 25% = 0.2250 ppm

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Barrier effect (laminate, edgebanding) - 95% = 0.0125 ppm

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Air change effect (Test rate is .5 changes/hour; x .125

4 changes used here; typical is 8-12) = 0.0014 ppm

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Lower temperatures and humidity levels decrease emissions even further.

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The 0.0014 ppm is much less than both the ANSI standard of 0.3 ppm for manufactured product and the potential effect level of 0.1 ppm.

Even if the above conditions are diluted by half, the .031 ppm result is still well below the permissible levels.

Conclusion

Standard particleboard core casework and tops, made with particleboard meeting ANSI A208.1 and properly laminated and edgebanded, should easily surpass formaldehyde emission requirements.

Additional Information

U.S. Consumer Product Safety Commission

Washington, D.C.
800/638-2772
www.cpsc.gov

Composite Panel Association

Gaithersburg, MD
301/670-0604
www.pbmdf.com

Case Systems, Inc.

Midland, MI
989/496-0773
www.casesystems.com
marketing@casesystems.com