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t .LJJ. Research Triangle Pdrk, North Carolina 27711

Clarification of Degreasing RegulationRequirements

Richard G. Rhoads, Directo

Control Programs Development Division (MD-l5)

flh-ector, Air and Hazardous tiaterials Division, Regions I, 1I1—X

Director, Environmental Programs Division, Region II

It has come to my attention that the existing guidance in the control technology guideline (CTG) for solvent metal cleaning operations was not sufficiently explicit. The following questions and answers should clarify any remaining ambiguity in this area.

For urban nonattainment areas (>200,000 population), what are the appropriate exemptions for solvent metal cleaning operations?

The only exemptions which would generally be allowed are those explicitly provided for in th preface 2f the CTG. Namely, conveyoriec degeasers smaller than 2.0 m (21.5 ftj of air/vapor interface should he e>:empted from the requirement or a majo control device and open top vapor degreasers smaller than l m (10.8 ft ) of open area should be

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exa’pt from the application of refrigerated chillers (or carbon adsorbe).

the board exemptions for small sources (e.g., 3 lb/day) should not he approved. Because of the latge number of small metal. cleaning operations in existence, an exemption of this nature wouli significantly

reduce the overall effectiveness of the controls program in this CTG catqory. ie recognize that for cold cleaners (batch operated, non—

bol solvent degreasers typically oi the type found in automotive repair facilities) these limits will be difficult to enforce. However,

since the sources are sc ubiquitous, we feel it would be preferable o

set requirements whichare applicable to similar pieces of equipment

throughout the industry and prioritize enforcement rather than exempt

particular sectors because of the difficulty with enforcement.

For rural nonattainment areas, what are appropriate exemptions for

solvent metal cleaning regulations?

Besides those exemptions listed above for urban areas, the policy

allows exeiptions for sources less than 100 tons/year. Hence, an exemp

tion for all cold cleaners in rural nonattainment areas would he approvable since a typical cold cleaner emits approximately 0.3 tons/year. However,

States should not exempt all open top vapor degreasers or conveyorized

degreasers which individually emit less than 100 tons/year in rural nonattainment areas because large scale users may have over 100 separate degreasing operations at one plant location. I-f a State chooses to exempt

open top or conveyorized degreasing operations in rural nonattainment

areas, the limitation-should be 100 tons or less on a facility—wide

basis based on annual solvent purchase records. Further, any exemption

FORM 3?3-G (FV. 3-76
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which distinguishes between open top vapor degroasers and conveycrized degreasers should not be approved because of the potential of switching between equipment types. Although conveyorized decjreasers are larger eriitters, they emit significantly less solvent than do open top vapor de-2aars for an equivalent workload. Thus, ‘it would not be advantageous to encourage degreaser operators to choose open top vapor degreasers in order to avoid regulations on conveyorized degreasers.

The CTG for solvent metal cleaning identifies a Control System A and a Control System B. Under what circumstances are each appropriate?

States should be encouraged to control all sources to Control System B level.

Al] tirban nonattainrent areas seeking en extension, and all facilities

emitting in excess of 100 tons/yr in a nonattainment area, must apply

Contra] System B.

cc: Chief, Air Branch, Regions I-X

Don Goodwin, Director. ESED

David Patrick, ESED

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