Chemical Engineering February 2016 - 18

VoC HealtH effeCts, limits and measurement
A
lthough definitions for volatile organic compounds (VOCs) can vary depending on the
context, the key aspects for paints and coatings involve organic compounds with low
boiling points that can undergo chemical reactions in the atmosphere as a result of
interaction with ultraviolet radiation. Aliphatic hydrocarbons, acetone, ethyl acetate, glycol
ethers and others are VOCs that have been used as ingredients in paint and coating formulations.
Health effects of VOCs generally depend on the concentration in the air, and on how
long and how often a person breathes the air. Acute effects can be eye, nose and throat irritation,
nausea, headaches and exacerbation of asthma symptoms. Chronic exposure to high
levels of VOCs can increase the risk of certain types of cancer, liver and kidney damage and
the risk of damage to the central nervous system. for more information on health and VOCs,
visit the Indoor Air Quality Scientific findings resource Bank (iaqscience.lbl.gov).
In the u.S., VOCs in paints are regulated by the Environmental Protection Agency (EPA;
Washington, D.C.; www.epa.gov). federal VOC limits are now set at 250 grams per liter (g/L)
for flat paints and 380 g/L for others. The establishment and evolution of VOC limits for paint
has seen a large degree of input from industry. " The whole history of VOCs in paint is a good
example of how industry can work with government to produce win-win situations, " Golton
says. There are now much better-performing paints with much lower VOC content. So the
public got less pollution and the paint manufacturers got better paint.
Some states and regions have lowered the VOC levels for paints that can be legally sold
in their areas beyond those required by u.S. federal regulations. for example, California's
standards are more stringent: 150 g/L for nonflat finishes and 100 g/L for flat. In areas where
smog can be a public health problem, the limits go further. The South Coast Air Quality Management
District (SCAQMD; Diamond Bar, Calif.; www.aqmd.gov), the air-pollution control
agency for the areas surrounding Los Angeles, has set an even more ambitious limit - 50 g/L
of VOC for all finishes. So-called " super-compliant " products meet a standard of less than 10
g/L, explains Sam Atwood of the SCAQMD. He says that over the past 20 years, more than
50 ton/d of VOC emissions have been reduced from architectural coatings through four major
rule amendments and a fee/reporting rule adopted in 2008, which has provided incentive to
manufacturers to further lower VOC emissions.
Legislation to limit and lower VOC emissions are becoming more common elsewhere also.
The European union has reduced VOC limits in regulations put forth in 2007 and again in
2010. Also, its rEACH legislation on chemical toxicity affects VOC use. China is moving to
limit VOCs because of air-quality issues resulting in part from rapid development.
Measurement. Measurement of VOCs has historically been an imprecise process. EPA's
Method 24 is said to be unreliable for paints with very low levels of VOCs. At lower VOC levels,
the test has had a difficult time achieving accurate measurements. In its new GS-11 standard
(see box, p. 20), GreenSeal says it has incorporated a more direct method into the standard
that produces a more accurate reading as the amount gets smaller. The test is estimated to
be 10 times more effective and improves further as the VOC gets closer to zero
" The old Test Method 24 was set up a long time ago, when a lot of the companies didn't
have big laboratories, " says former consultant Golton. " That meant it had to be easy to do,
but the rudimentary test was never intended to measure VOC levels below 100 g/L. " A newer
test method, ASTM D 6886 is based on gas chromatography, and has gained wide acceptance
in the u.S. A similar method is the standard in Europe.
The SCAQMD is aware of those drawbacks and uses Method 313-91, which is supposed to
be more accurate for no- and low-VOC paints. Although companies acknowledge the unreliability
of Method 24, it remains the only method that can be used for certification. The EPA
has not yet revised Method 24 to give manufacturers another option.
ager for PPG Architectural Coatings
(Pittsburgh, Pa.; www.ppgac.com)
in the u.S. and Canada.
The shift to new materials has required
much effort to negotiate the
tradeoffs that arise among the various
attributes of paints and coatings.
" In the past, the perception
was that a better environmental
profile necessarily meant a sacrifice
of performance, but the industry
has improved significantly in
both environmental and paint performance,
a tradeoff between the
18
two may not be necessary, " says
AkzoNobel's Cook.
Eastman's Murray Hemsley
agrees: " Companies understand that
consumers are not usually willing to
trade off quality for sustainability, and
through hard work and formulation
expertise, paint formulators are very
close to matching the performance
of conventional paints [with their
low-VOC products]. "
AkzoNobel's Cook says performance
improvements for low-VOC
paints have been made " across the
board, but especially at the higher
price points. " One issue that remains
for low-VOC is glossiness - a highgloss
finish with no brush marks is
still hard to achieve with water-based
products, Cook notes.
Zero-VOC paints
While the proliferation of low-VOC
(designated by VOC levels lower than
250 g/L) coatings products continues,
there is a considerable push to
achieve much lower levels than that
in many market segments. Paint sellers
such as Benjamin Moore, Sherwin-Williams
and several others have
pushed the VOC levels lower, to a
point where they can be marketed
as " zero-VOC " paints. Truly zeroVOC
paints do not exist, says former
industry consultant Golton, but the
levels in these paints are less than 5
g/L of VOCs in order to be classified
as " zero-VOC. "
Benjamin Moore's zero-VOC product
lines Natura and ultra Spec are
among the growing offerings. " In
the past you could expect lower
levels of durability, or perhaps different
application characteristics [for
zero-VOC], " says Glenn Cooper, vice
president of product development for
Benjamin Moore, " but we have really
conquered those issues now. "
Health risks also have decreased.
The zero-VOC Natura brand, for example,
has been certified asthmaand
allergy-friendly by the Asthma
and Allergy foundation of America,
Cooper notes.
PPG offers the PPG Pittsburgh
Paints Wonder-Pure brand, a zeroVOC
interior latex paint and related
primer with low odor, which allows
painters and maintenance professionals
to paint in occupied spaces
with little disruption, PPG says.
New additives
Although typically accounting for
only 0.5-5.0 wt.% of a paint, additives
play a critical role in the
paint's properties, including those
having to do with environmental
and health impact. research and
development investment over the
past several years on new additives
for paints and coatings is now
bearing fruit. Chemical companies
ChemiCal engineering www.Chemengonline.Com february 2016

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Chemical Engineering February 2016

Table of Contents for the Digital Edition of Chemical Engineering February 2016