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Abstract

This page describes VOC levels in plywood, which is a standard United States of America home construction material.

Introduction

Plywood is the one of the main types of wood used in the construction of our homes. It has remained popular in United States construction, due to it's strong structure, durability, and ease of use. It is commonly used as flooring, siding and other frame work. The structure of plywood is interesting as it uses thin cuts of wood, veneers as they are called. These veneers are glued together with the grain at a right angle of the opposing sheet or veneer.This adds strength and flexibility as the wood has several different angles to keep the stability of the board.[1]Although plywood has remained popular it has become under more scrutiny due to the fact that the adhesives used contain formaldehyde.

Plywood view from the side[2]


Adhesive resins have been used since the 1870's when they were accidentally discovered. These resins have become increasing cheaper and gained more use with the consumer surplus in the 1950's along with the invention of particle board. Particle board is similar to plywood, it is composed of small chips of wood that are pressed together bonding with formaldehyde resins. Particle board usually is found inside the house as it cannot handle moisture as well as plywood. Also, it does not have the strength that plywood has, in return particle boards can be commonly found as the basis for cabinets and furniture.[1] Particle board also is cheaper than plywood.

Particle Board, notice the chips of wood[3]

The major dilemma with the use of the formaldehyde resin is the slow release of formaldehyde as the bonds break apart due to heat and moisture. [4] According to the Environmental Protection Agency,Formaldehyde is "a colorless, pungent-smelling gas, can cause watery eyes, burning sensations in the eyes and throat, nausea, and difficulty in breathing in some humans exposed at elevated levels (above 0.1 parts per million). High concentrations may trigger attacks in people with asthma. There is evidence that some people can develop a sensitivity to formaldehyde. It has also been shown to cause cancer in animals and may cause cancer in humans. Health effects include eye, nose, and throat irritation; wheezing and coughing; fatigue; skin rash; severe allergic reactions. May cause cancer."[5]

Use and Consumption

"U.S. demand for hardwood plywood is principally derived from demand for cabinets, furniture, store fixtures, recreational vehicles, and manufactured homes," according to the united states intentional trade commission.[6] A Majority of the plywood is made from domestic wood, although their are imports "U.S. firms purchased 72 percent of their wood from domestic sources and 19 percent from Canadian sources,[6] in 2006. As we can see the demand for plywood has remain strong and with a large amount produced domestically. See table below also remember we had a housing market crash yet the production remained high.

Stacks of Lumber[7]
US plywood Consumption 2003 2005 2007
Millions of dollars 1,745 2,275 2,412
Millions of square feet 3,428 4,397 3,954

VOC Levels

The main VOC that is tested in plywood is formaldehyde. It can either be measured by the amount of formaldehyde released from the product measured in parts per million or amount in the product usually measured in mg/g.[8] With increasing concern and consumer interest in eco-friendly products, the United States may begin stricter regulations. The table below shows the current regulations for plywood, although companies have to pass these regulations they are not required to label their products with the results.

Current Regulations Formaldehyde Emission
Department of Housing and Urban Development 0.3 ppm
American National Standards Institute 0.2 ppm
German Standard 0.1 ppm

Products

The product choice is up to the consumer. Many companies do not show the amount of Formaldehyde levels in their plywood or particleboard. Some companies like Columbia Forest Products advertise their ability to create comparable products without the use of formaldehyde resins.[1] Their product is available for purchase at most home depots. The adhesive that is used is soy-based. This came after a University of Oregon professor tried to mimic the actions of muscles. Muscles can remain attached to rocks even through rough surf. The protein the muscles use is similar to soy protein. Professor KaiChang Li and his colleagues, "went ahead and found a good curing agent and basically cross linked the soy protein to make it stronger.[9] This has created a formaldehyde free product for a relatively comparable price. The table below is the cost of different sheets of plywood and their costs.[10]

Brand Name Product Cost Formaldehyde?
Millstead 3/4 in. x 4 ft. x 8 ft $39.95/EA Yes
PureBond® 3/4 in. x 4 ft. x 8 ft $46.97/EA No
Millstead 1/4 in. x 4 ft. x 8 ft $19.96/EA Yes
PureBond® 1/4 in. x 4 ft. x 8 ft $25.97/EA No

Alternatives

Wood glues- Even for your household projects the wood glue you may use might also contain a formaldehyde. Their is a product by Eclectic products a company from Oregon that has a wood glue that is non-toxic and rivals in strength test with name brands. Check out there site or ask your local hardware store. [2]

Type of glue Ounces Cost
EcoGlue® Premium Wood 16 $8.22
Titebond Original Wood Glue 16 $8.04


Cabinets- Using stainless steel cabinets would be VOC free. Although if you still like the appearance of the traditional cabinets there are companies like SierraPine that produce Particle boards without any added formaldehyde resins and use sources like bamboo and wheat instead of the traditional wood.[3]

See Also

References

7. Interaction of volatile organic compounds with indoor materials—a small-scale screening method, Atmospheric Environment,Volume 33, Issue 15, 1 July 1999

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