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Re: Fw: Styrene



Hi Kevin,
 
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The  EPA's AP-42 emission factors for polyseter resin products fabrication were withdrawn on 3/18/1998 and have not yet been replaced. 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 noting:
 
EPA/600/SR-97/018, September 1997: Evaluation of pollution prevention techniques to reduce styrene emissions from open contact molding processes.
 
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 plastics industry
 
These may still be available at http://www.epa.gov/ncepihom/catalog.html 
 
 
Bill Quinn
ADEQ
Pollution Prevention Unit
Phone: 602-207-4203
Fax:      602-207-4538
Website: wwwadeq.state.az.us/environ/waste/capdev/p2/index.html

>>> "Kevin Dick" <dick@unr.edu> 08/17/01 03:13PM >>>
I received a request to forward this to these listservs from a non-listserv
subscriber.  In addition to a listserv reply please reply directly to:

Kevin Gieschen
805 583-6462
Kgiesche@simivalley.org


> I am working with a bathtub/spa manufacturer that  uses gelcoat and
fiberglass to manufacture these products. There is an odor (assumed health)
problem with their manufacturing and curing processes. The odor is from
primarily the styrene. The question is does anyone have experience/examples
of P2 techniques (IE product substitution etc.) that would reduce or
eliminate these chemicals? They have activated carbon control on 3 of their
4 stacks, but the real problem is the chemicals and what is being  emitted
into and outside of the building .
> Tough question I know. Thanks in advance for any assistance.
>
>