Mr. Win Sabatka, President
Finishing Equipment, Inc.
3640 Kennebec Drive
St. Paul, MN 55122

RE: Halogenated Solvent Cleaning NESHAP

Dear Mr. Sabatka:

     Thank you very much for your continued interest in compliance issues associated with the
Halogenated Solvent Cleaning NESHAP (Part 63, Subpart T).  We have reviewed your letter
concerning the need to increase the freeboard ratio on enclosed design machines.  In summary,
you assert that the need to increase the freeboard ratio to 1.0 or to use a cover on a machine with
what you term a "total enclosure" is not necessary. You describe your "total top enclosure" to
include a horizontal part entry port as opposed to the enclosed design with a vertical entry port. 

     Under the NESHAP, you are allowed to comply using a freeboard ratio of 1.0, reduced
room draft or working-mode cover, and superheated parts technology.  One of the alternatives for
demonstrating compliance with the reduced room draft is through the use of an enclosed design.
Your units include the superheated parts technology and achieve the reduced room draft by means
of your "total top enclosure" (hereinafter called a horizontal port enclosed design).  You have
suggested that this horizontal port enclosed design also be allowed to meet the requirement of a
cover, and the 1.0 freeboard ratio.

          While the rule does not distinguish between a horizontal port enclosed design and other
     enclosed designs, the supporting information for this rulemaking did.  On page 3-37 of the
     "National Emission Standards for Hazardous Air Pollutants: Halogenated Solvent
     Cleaning - Background Information Document" (EPA-453/R-93-054, November 1993)
     the EPA notes that "the enclosed design with a horizontal entry/exit port (Figure 3-13.A)
     is not affected by room air drafts."   The primary purpose of an increased freeboard is to
     reduce the impact of room drafts across the lip of a cleaning machine.  An enclosed design
     that eliminates any and all potential for drafts achieves the same purpose of an increased
     freeboard. 
          When measuring a freeboard ratio, the numerator is the height of the freeboard area.  This
     measurement is taken because the top of the freeboard area is typically the point where
     ambient air and room drafts can impact the cleaning machine.  Clearly, on units with
     horizontal entry ports, this is not the case.   In cases where units with horizontal entry
     ports are designed such that no air currents can travel up the port and into the machine, 
     EPA agrees that increasing the actual freeboard height will not result in any additional
     emissions reductions.

          Covers, both working-mode and down-time, are used on halogenated solvent cleaning
     machines to eliminate drafts within the freeboard and to reduce diffusion losses.  As
     discussed in the background information document for the halogenated solvent cleaning
     NESHAP an enclosed design, such as the horizontal port enclosed design, completely
     encloses the solvent cleaning machine except for a single opening through which parts
     enter and leave the enclosure. Such enclosed designs reduce idling and working emissions
     by creating a still air environment inside the solvent cleaning machine, which limits solvent
     diffusion.  Furthermore, the preamble to the proposal of the halogenated solvent cleaning
     NESHAP (58 FR 62576) states that "an enclosed design is considered to exert equivalent
     control as a reduced room draft, and a cover."  Therefore, an enclosed design that
     eliminates any and all potential for drafts achieves the same purpose of a cover. 

     In conclusion, the EPA agrees that a reasonable equivalent compliance alternative for
batch cleaning machines is the horizontal port enclosed design combined with superheated vapor
technology.  The horizontal port entry should achieve at least the same emission reduction as the
combination of a reduced room draft and an increased freeboard ratio, and the combination of a
working-mode cover and an increased freeboard ratio.  This is, of course, contingent upon the
owner or operator's ability to demonstrate that no air currents are introduced around the machine
that would travel up the horizontal entry port and into the machine.  Again, we thank you for your
interest in exploring innovative options to help the regulated community implement the
halogenated solvent cleaning NESHAP standards.  Please contract Tracy Back (202-564-7076)
with any questions regarding this NESHAP.



                                   Sincerely,


                                   Elliott Gilberg, Director
                                   Chemical, Commercial Services and  
                                     Municipal Division


cc: 
Paul Almodóvar, OAQPS
Charlie Garlowe, ORE
Patricia Embry, OGC