Section 61.152 - Air-cleaning(a) The owner or operator who uses air cleaning, as specified in §§ 61.142(a) , 61.144(b)(2) , 61.145(c)(3)(i)(B) (1), 61.145(c)(4)(ii), 61.145(c)(11)(i), 61.146(b)(2), 61.147(b)(2), 61.149(b), 61.149(c)(1)(ii), 61.150(a)(1)(ii), 61.150(a)(2)(ii), and 61.155(e) shall:(1) Use fabric filter collection devices, except as noted in paragraph (b) of this section, doing all of the following:(i) Ensuring that the airflow permeability, as determined by ASTM Method D737-75, does not exceed 9 m3/min/m2 (30 ft3/min/ft2) for woven fabrics or 113/min/m2(35 ft3/min/ft2) for felted fabrics, except that 12 m3/min/m2 (40 ft3min/ft2) for woven and 14 m3/min/m2 (45 ft3min/ft2) for felted fabrics is allowed for filtering air from asbestos ore dryers; and(ii) Ensuring that felted fabric weighs at least 475 grams per square meter (14 ounces per square yard) and is at least 1.6 millimeters (one-sixteenth inch) thick throughout; and(iii) Avoiding the use of synthetic fabrics that contain fill yarn other than that which is spun.(2) Properly install, use, operate, and maintain all air-cleaning equipment authorized by this section. Bypass devices may be used only during upset or emergency conditions and then only for so long as it takes to shut down the operation generating the particulate asbestos material.(3) For fabric filter collection devices installed after January 10, 1989, provide for easy inspection for faulty bags.(b) There are the following exceptions to paragraph (a)(1):(1) After January 10, 1989, if the use of fabric creates a fire or explosion hazard, or the Administrator determines that a fabric filter is not feasible, the Administrator may authorize as a substitute the use of wet collectors designed to operate with a unit contacting energy of at least 9.95 kilopascals (40 inches water gage pressure).(2) Use a HEPA filter that is certified to be at least 99.97 percent efficient for 0.3 micron particles.(3) The Administrator may authorize the use of filtering equipment other than described in paragraphs (a)(1) and (b)(1) and (2) of this section if the owner or operator demonstrates to the Administrator's satisfaction that it is equivalent to the described equipment in filtering particulate asbestos material.49 FR 13661, Apr. 5, 1984; 49 FR 25453, June 21, 1984, as amended at 51 FR 8199, Mar. 10, 1986. Redesignated and amended at 55 FR 48430, Nov. 20, 1990