## I 1’ -.1

. t .LJJ. Research Triangle Pdrk, North Carolina 

### 27711 Clarification ofDegreasing 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 tomy attention thatthe existing guidance in the control technology guideline (CTG) for solventmetal cleaning operations 

### was not sufficiently explicit. The following questions and answers 

### should clarify any remaining ambiguity in this area. For urban nonattainment areas (>200,000population), what 

### are the appropriateexemptions for solventmetal cleaning operations? The only exemptions whichwould generallybe allowed are 

### those explicitly provided for in th preface 2 ftheCTG. Namely, conveyoriec degeasers smallerthan 2.0 

### m (21.5 ftj 

### ofair/vaporinterface should he e>:empted from the requirement or

### a majo control device and open top 

### vapor degreasers smaller than l m (10.8 ft

## ) ofopen area should be exa’pt fromthe application ofrefrigerated chillers (or carbon adsorbe). Acrs the board exemptions for small sources (e.g., 3 lb/day) should 

### not he approved. Because ofthe latge number ofsmall metal.cleaning operations in existence, an exemption ofthis nature wouli 

### significantly reduce the overall effectiveness ofthe controls program in this CTG catqory. ie recognize that forcold 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 itwould be preferable o set requirements whichare applicable to similar pieces 

### ofequipment throughout the industry and prioritize enforcementrather than exempt particular sectors because 

### ofthe difficultywith enforcement. For rural nonattainment areas, what are appropriate exemptions for solventmetal cleaning regulations? 

### Besides those exemptions listed above forurban 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 vapordegreasers or conveyorized 

### degreasers which 

### individually 

### emit less 

### than 100 tons/year in rural non

### attainment 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. 3-762 which distinguishes between open top vapordegroasers and conveycrized degreasers should not be approved because ofthe potential ofswitching between equipmenttypes. Although conveyorized decjreasers 

### are larger eriitters, they emit significantly less solventthan do open top vapor de-2aars for an equivalentworkload. Thus, ‘itwould not be advantageous to 

### encourage degreaseroperators to choose open top vapor degreasers in order to avoid regulations on conveyorized degreasers. The CTG forsolventmetal cleaning identifies a Control SystemA and a Control System B. Underwhat circumstances are each appropriate? States should be encouraged to control all sources to Control SystemB 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] SystemB.

cc: Chief, AirBranch, Regions I-X Don Goodwin, Director. ESED 

### David Patrick, ESED 

# )



# .