Section 226.155  Total Enclosure

a)         An owner or operator of a lead emission unit subject to this Part must install, maintain, and operate one or more total enclosures to minimize fugitive emissions from the operations listed in subsections (a)(1) through (6) at all times that the applicable lead emission unit in the total enclosure is operating or housekeeping activities are being performed.  The total enclosure must meet the requirements specified in subsections (b) through (e).

1)         Battery breaking areas.

2)         Dryer and dryer areas, including transition pieces, charging hoppers, chutes, and skip hoists conveying any lead-containing material.

3)         Reverberatory furnaces or rotary furnaces charging any lead-containing material and the associated reverberatory furnace areas or rotary furnace areas, including any associated lead taps, slag taps, and molds during processing. 

4)         Alloying and refining kettles and associated areas, including any associated lead taps, slag taps, and molds during processing. 

5)         Areas where dross, dust from fabric filters, sweepings, or used fabric filters are handled, except for areas where all such materials are in closed, leak-proof containers at all times.

6)         Material handling areas for any lead-containing materials.  The following areas are exempt from the total enclosure requirements unless the areas listed also contain operations listed in subsections (a)(1) through (5):

A)        Those areas where refined lead is melted and cast;

B)        Those areas where spent refractory brick is stored in closed containers prior to and after crushing;

C)        Those areas where ladle repairs take place; or

D)        Those areas where lead-bearing scrap is sorted and handled, if the area is enclosed and equipped with a capture system ducted to a control device subject to the requirements of Section 226.140(e) during all sorting and handling activities and if the scrap is stored in closed containers at all other times.

b)         An owner or operator of a lead emission unit subject to this Part must duct the gas stream collected by each total enclosure to a control device that meets the applicable requirements of Section 226.140.

c)         The total enclosure must be maintained and operated with an inward flow of air through all natural draft openings while the lead emission unit applicable to the operation listed in subsection (a) in the total enclosure is operating.  The average facial velocity of air flowing into the enclosure through all natural draft openings during operation of lead emission units in each total enclosure in any one hour period must be at least 200 fpm (3,600 m/hr) or an average negative pressure value of 0.007 inches of water (0.013 mm Hg) must be maintained inside the enclosure over any one hour period.

d)         The total enclosure required by subsection (a) must be maintained at any opening, including, but not limited to, vents, windows, passages, doorways, bay doors, and roll-ups while lead emission units in the total enclosure or enclosures are operating, except as needed for temporary access to conduct manufacturing operations (e.g., during load-in and load-out of materials or passage of personnel or equipment).

e)         The total enclosure must be free of cracks, gaps, corrosion, or other deterioration that could cause or result in dust being emitted to the atmosphere through those openings, except that the total area of all natural draft openings must not exceed 5 percent of the surface area of the total enclosure's walls, floor, and ceiling.