In response to Mike Callahan's 8/24/01 inquiry asking
why the EPA may not like the controlled spraying program: The EPA sent a
letter to the Composites Fabricators Association on April 29, 1998
responding to CFA's request that the EPA Office of Compliance &
Enforcement evaluate and comment on the enforceability of the CFA's controlled
spraying program. I believe CFA suggested that the controlled spraying
program be added to the list of emission reduction techniques being considered
in the draft MACTstandards for open molding sources. EPA stated that: "Based
on our analysis of all of the information available, the Agency's position
continues to be .. that the controlled spraying program would not be
Some reasons given in the letter were: (1) the program has
many variabilities including product surface areas, skill levels of
technicians, % transfer efficiency during spraying, etc. , (2) there is
not a practical way to quantify emission reductions which is necessary to
issue credits for the MACT program, (3) additional monitoring, recordkeeping
and reporting requirements would be necessary and there would be a burden in
maintaining detailed records, especially for small
The folks at CFA or EPA may be able to state if there has been any
additional discussion on this subject.
"Callahan, Mike" <Mike.Callahan@Jacobs.com> 08/24/01 04:28PM
Thanks for bringing this
great website to everyone's attention. Do you have any background
on why the EPA won't allow the use of controlled spraying? I think that
the CFA is right on the money with this one. Training is one of the most
important factors in reducing emissions from any spray coating
operation. I just read one of the CFA reports and I fully agree that
emissions reduction can be achieved through training and by controlling the
spray so you don't coat areas you don't want to coat. This is the
one big error of all transfer efficiency tests.
My guess is the EPA would
prefer to maintain a command and control approach because it is easier to
enforce. We ran into this in the automotive refinishing industry where
the air agencies insisted on the conversion from air spray to HVLP spray
guns. While available data at the time showed potential reductions to be
the same for HVLP versus conventional air spray with training, the push to
HVLP went on. I hope the CFA has better luck. Just my two
From: Bill Quinn
Sent: Friday, August 24, 2001
Subject: Re: Fw: Styrene
Since your note did not state what manufacturing methods the
bathtub/spa manufacturer uses now (i.e. are they casting cultured
marble and using gelcoat or just using fiberglass and resin/gelcoat, I
will generalize here.
The EPA's AP-42 emission factors for polyseter resin
products fabrication were withdrawn on 3/18/1998 and have not yet been
Section 4.4 of AP-42 was removed because the emission
factors presented in that section appeared to under predict styrene
emissions from most polyester resin operations. Many Arizona shops are now
using Arizona's Maricopa County emissions factors for polyester resins which
are currently based on the Composites Fabricator Association's (CFA)
emissions tables. The exception is that the EPA has said they will not
allow use of the column for "controlled spraying." The CFA table can be seen
as Table 2.16 in the document located at http://www.epa.gov/ttn/chief/efdocs/cfa_rpt3.pdf
This table is helpful if one wants to be able to calculate a
styrene emission reduction because it shows the allowable P2 techniques. As
seen on the table hedings, to reduce styrene emissions, one can
use vapor supression, change to a non-atomized application instead of a
spray gun, use a manual resin application, use a resin or gel coat with
less styrene %, or change to a closed molding process.
Judith Kennedy already responded with very helpful information and
websites to review.
In my experience here, the best emission reduction one can do in open
molding is to install a resin flow coater/chopper to replace a spray/chopper
gun. This works if your are using resin and fiberglass chop.
It is not used here for gel coat. This flow coater application
would be used only of the facility is using chopped fiberglass in their
products. For cast cultured marble operations, some Arizona faclilties use
chopped fiber glass on the back of their cast cultured marble products for
strength and to lighten the marble casting.
Another possibility is to use a resin or gel coat with a lower % of
styrene, but you must be careful to not degrade the finished product.
One of our Arizona facilities (Arizona Marble) is using a manually
applied gel coat or brushable gelcoat (product code G1117, distributed
by HK Research Corporation, 38% styrene) on flat surfaces.
Lastly, Judith mentioned controlled spraying. A facility
can easily implement the controlled spraying program developed by
CFA. EPA does not allow an emissions reduction for such a program, but
it does make sense to implement this simple program. This program involves
(1) simple spray operator training, (2) proper spray gun pressure
calibration, and (3) use of flanges on molds to reduce
overspray. This program can be downloaded from the bottom of
the page at: http://www.cfa-hq.org/techsvcs.shtml
The download includes an instructor guide and a student handbook.
It is important to also review the ventilation system and spray booths
to be sure it they are designed and operated properly to protect public
and worker health.
There are several other EPA documents on this subject that are worth
EPA/600/SR-97/018, September 1997: Evaluation of pollution prevention
techniques to reduce styrene emissions from open contact molding
EPA/600/SR-96/138, December 1996: Evaluation of styrene emissions from
a shower stall manufacturing facility.
EPA/625/7-91/014, October 1991: The fiberglass-reinforced and composite
Pollution Prevention Unit
"Kevin Dick" <email@example.com> 08/17/01 03:13PM >>>
received a request to forward this to these listservs from a
subscriber. In addition to a listserv reply please
reply directly to:
> I am working with a
bathtub/spa manufacturer that uses gelcoat and
manufacture these products. There is an odor (assumed health)
with their manufacturing and curing processes. The odor is from
the styrene. The question is does anyone have experience/examples
techniques (IE product substitution etc.) that would reduce or
these chemicals? They have activated carbon control on 3 of their
stacks, but the real problem is the chemicals and what is being
into and outside of the building .
> Tough question I know.
Thanks in advance for any