Letter to AFMA from Keith Overcash (September 3, 1998)

September 3, 1998

Mr. Andy S. Counts
Director of Environmental Affairs
American Furniture Manufacturers Association (AFMA)
223 South Wrenn Street
PO Box HP-7
High Point, North Carolina 27261

Dear Mr. Counts:

I feel that our meeting of August 5 was extremely productive, even though we did not reach agreement on all topics mentioned in your July 13, 1998 letter. However, I believe that we continue to make progress toward a better understanding of mutual problems and limitations. I also appreciate your agreement to include Roy Huntley of USEPA, so that we could more efficiently search for optimal long term solutions.

I would like to summarize several of the advances that were made during our discussions and outline directions that the Division of Air Quality (DAQ) feels would be most productive toward resolving the remainder. Please advise as soon as possible if I have incorrectly or inappropriately included or excluded any statements that are counter to your understanding.

Woodworking and Finishing Operations
It was agreed that plant specific calculations of "% yield" for wood waste quantity determinations were reasonable and common practice. There had been a misunderstanding that we were making a new request for unique particle-size characterization (tests) specific to waste wood at each plant, which was not the case. The information cited in the April 26, 1995 memorandum from Laura Butler is indeed still used as a standard guide for staff in reviewing typical plant-wide waste data. As needs for particle size information on PM-2.5 are determined, such specifications may expand; therefore we encourage you to collect such information in future tests.

It was agreed that the operation and control efficiencies of baghouses were not an issue. We also agreed that visible emissions from a baghouse is a reliable indicator of malfunction of these devices, and suggest improper or inadequate maintenance. Inspectors will normally discuss any such observations with the plant and the plant log should be appropriately annotated.

We discussed data AFMA has supplied for paint booth over-spray that relates to determination of particle size distribution (and particularly, what part is > 10 micrometers). Mike Aldridge indicated that his staff would review these data as soon as possible.

The factors mentioned in your letter [2.11 pounds of VOC/thousand board feet (mbf) for pine, with 0.211 pounds/mbf assumed for hardwoods] were derived from industry testing performed on units in our Washington region. Later tests on the same units indicated a higher value of 3.1 pounds/mbf, which is the number our regions were using for reviewing inventories. However, this has not been done consistently in all our regions. There are also other remaining considerations; a) need to report as actual mass, rather than "as carbon;" b) tests (which we do not currently have copies of) at one large eastern NC wood products company are reported to be averaging 3.4 lb/mbf (That company is using 3.8 lb/mbf which is the conservative "two standard deviation range," for their estimates); and c) there is additional testing data evaluation underway by the National Council for Air and Stream Improvement (NCASI), due to be reported upon in final form before the end of this calendar year. In view of these several points, the DAQ agrees that the industry's use of 2.11/0.21 in the 1997 inventory should not be modified while we compile and jointly review this and any other additional similar research information. We encourage AFMA to jointly review the new information from NCASI prior to new factors being adopted for future inventory and permit purposes. If the NCASI information is not forthcoming by the end of the calendar year, to allow for its use in the CY 1998 inventories and permit applications submitted during that time, we will view the 3.4 lb/mbf number supplied and adopted by the aforementioned wood products company as the appropriate guide ("best and available information") for pine. For hardwoods, a 10% of pine assumption will still be acceptable, absent test data to the contrary.

Carbon Monoxide and Particulate Matter From Dry Wood Combustion
Our main remaining disagreements center on emissions for "dry" wood combustion in boilers. AP-42 clearly states in the text, and as a footnote to the tables, that the factors are based on tests with wood that was 50% moisture with a heat content of 4500 Btu/lb. When the fuel differs significantly from this basis, direct use of the "unadjusted" factors as stated in AP-42 (on a weight basis) is not appropriate. The DAQ continues to point out that when you put the test data and factors for combustion of wood on a pounds of particulate matter per million Btu-basis (lb/mmBtu), the wet/dry "correction" goes away. Both EPA and the DAQ feel that appropriate compensation should be made for particulate matter and CO, based on the Btu content (moisture content) of the fuel. Using "after control" (multi cyclones -approximately 52% efficient for particulate matter, w/o flyash reinjection) emissions, on a lb/mmBtu basis, the AP-42 values, our Asheville Region's partial compilation of test values, and your compilation of test values, are not grossly different for particulate matter. When you assign a higher control efficiency than 52% to the particulate matter control devices (in the absence of test data), we will likely disagree on the estimates.

The DAQ believes that estimating Carbon Monoxide (CO) emissions, on the same (lb/mmBtu) basis as particulate matter, is also appropriate until test data are compiled and reviewed. We recognize that we continue to disagree on this point.

We agree that all parties (AFMA, DAQ and USEPA) should jointly undertake efforts to complete testing and data evaluation to confirm, or refute, the points related to moisture effects on emissions, and develop data more specific to actual dry wood conditions. Further, it is our understanding that you are agreeable to locating and providing three to five appropriate and representative facilities (to be defined for review before final selection) and funding the testing for criteria pollutants from these facilities. EPA will provide support and has requested additional budget for the systematic analysis of existing and new data. DAQ is agreeable to reviewing site selection proposals, test protocols and test reports, and providing on-site observation of the tests. As soon as actual validated data are available and appropriately compiled, we can move forward to use such data for other similar and applicable facilities.

In the interim, for all new and modified sources, the DAQ insists that you use the AP-42 values on a lb/mmBtu basis or conduct stack tests. Furthermore, for any previous new or modified sources, a situation may exist where such actions trigger PSD or facility classification changes (ex. Title V, Synthetic minor, etc.). In any such situations the options are to file a new PSD application, a new Title V or other permit application, or test to show that the source's CO emissions are below the related threshold(s).

Thank you for the open, direct and productive discussions. I look forward to continuation of our dialogue and progress in the future.


B. Keith Overcash, P.E.
Deputy Director

Alan W. Klimek, P.E., DAQ
Jim Southerland, QEP, DAQ
Joseph A. Pendola, EIT, DAQ
DAQ Regional Supervisors
DAQ Section Chiefs
Alan McConnell, Kilpatrick Stockton LLP
Roy Huntley, EFIG, USEPA

Last Modified: Fri April 04 16:39:39 2014