Installations and Assembly

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Liquid coatings applied in factory settings are more
effective than on-site finishing in the control of
emissions because hoods and air currents typically
carry finishing solvents and other curing finish
residues away. When the factory-coated product is
installed, the finish is essentially cured and most
VOC emissions have already been released. On site
finishing usually depends on air-drying under
uncontrolled conditions that can result in greater
emission exposures and increased coating variability.
Powder coatings are a relatively recent addition to
factory wood product finishing options. Powder
coatings are applied as electrostatic solids and have
demonstrated their efficacy as a formaldehyde
emission barrier. As the use of these and other new
coating systems are commercialized, emission barrier
information on other VOC’s will be evaluated for
addition to this technical bulletin.
Wood Veneers
Veneers have been shown to be effective barriers for
some VOCs but only low to moderately effective for
formaldehyde. Non-porous woods such as maple
and birch are more effective diffusion barriers than
porous woods such as ash and oak. Low
permeability, high solids coatings applied to veneers
on standard wood composite substrates have the
potential for very low emissions of both
formaldehyde and other VOCs.
Wood veneers are frequently applied to particleboard
and MDF using UF adhesives. These veneer
adhesives create the potential for another source of
emissions and must be considered when evaluating
the overall VOC and formaldehyde emission
potential from such a system.
Emission Barrier Performance
Materials or combinations of materials are listed in
Table A under barrier effectiveness categories for
formaldehyde. Their evaluations are based on
laboratory studies and industry experience.
Category placement can be influenced by the nature
of the specific wood composite product to which
they are applied; the thickness of the laminate, film
or coating; the type of impregnating resin if
applicable; the indoor environment; and other
factors. Due to these factors, comparative technical
data demonstrating the effectiveness of the finish is
essential. Small-scale laboratory testing, such as
ASTM’s Standard Guide for Small-Scale
Environmental Chamber Determination of
Organic Emissions From Indoor Materials/
Products, ASTM D 5116-97, can be used to
quantify the effectiveness of the system in reducing
formaldehyde emission potential from the specific
product of interest. Emission barrier information
on other VOCs for the various decorative surface
finishes will be evaluated for addition to this
technical bulletin as they become available.