EPA air monitoring chain of custody, Jan 2003

NYC 9/11 Public Portal Document

t

4 « < • 7

ASBESTOS and OTHER FIBERS by PCM: METHOD 7400, Issue 2, dated 15 August 1994 - Page 15 of 15

APPENDIX C. ALTERNATE COUNTING RULES FOR NON-ASBESTOS FIBERS

Other counting rules may be more appropriate for measurement of specific non-asbestos fiber types, such as fibrous glass. These include the "B" rules given below (from NIOSH Method 7400, Revision #2, dated 8/15/87), the World Health Organization reference method for man-made mineral fiber [24], and the NIOSH fibrous glass criteria document method [25]. The upper diameter limit in these methods prevents measurements of non-thoracic fibers. It is important to note that the aspect ratio limits included in these methods vary. NIOSH recommends the use of the 3:1 aspect ratio in counting fibers.

It is emphasized that hybridization of different sets of counting rules is not permitted. Report specifically which set of counting rules are used with the analytical results.

"B" COUNTING RULES:

1. Count only ends of fibers. Each fiber must be longer than 5 pm and less than 3 pm diameter. 2. Count only ends of fibers with a length-to-width ratio equal to or greater than 5:1. 3. Count each fiber end which falls within the graticule area as one end, provided that the fiber meets rules 1 and 2 above. Add split ends to the count as appropriate if the split fiber segment also meets the criteria of rules 1 and 2 above. 4. Count visibly free ends which meet rules 1 and 2 above when the fiber appears to be attached to another particle, regardless of the size of the other particle. Count the end of a fiber obscured by another particle if the particle covering the fiber end is less than 3 pm in diameter. 5. Count free ends of fibers emanating from large clumps and bundles up to a maximum of 10 ends (5 fibers), provided that each segment meets rules 1 and 2 above. 6. Count enough graticule fields to yield 200 ends. Count a minimum of 20 graticule fields. Stop at 100 graticule fields, regardless of count. 7. Divide total end count by 2 to yield fiber count.

APPENDIX D. EQUIVALENT LIMITS OF DETECTION AND QUANTITATION

fiber density on filter* fiber concentration in air, f/cc fibers 400-L air 1000-L air per 100 fields fibers/mm^ sample sample

200 255 0.25 0.10 100 127 0.125 0.05 LOQ.... 80.... ,.102... ...0.10..... ...0.04 50 64 0.0625 0.025 25 32 0.03 0.0125 20 25 0.025 0.010 10 12.7 0.0125 0.005 8 10.2 0.010 0.004 LCD..... 5.5.. .... 7... ...0.00675, ....0.0027

* Assumes 385 mm ’ effective filter collection area, and field area = 0.00785 mm 2, for relatively "clean" (little particulate aside from fibers) filters.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94

NYC-WTC_000149415