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ASBESTOS and OTHER FIBERS by PCM:METHOD 7400,Issue 2,dated 15 August 1994-Page 15 of 15 <br /> 5. Count free ends of fibers emanating from large clumps and bundles up to a maximum of 10 ends(5 <br /> fibers),provided that each segment meets rules 1 and 2 above. <br /> 6. Count enough graticule fields to yield 200 ends.Count a minimum of 20 graticule fields.Stop at 100 <br /> graticule fields,regardless of count. <br /> 7. Divide total end count by 2 to yield fiber count. <br /> APPENDIX D.EQUIVALENT LIMITS OF DETECTION AND QUANTITATION <br /> Fiber density on filter* Fiber concentration in air,f/cc <br /> Fibers per 100 fields Fibers/mmZ 400-L air sample 1000-L air sample <br /> 200 255 0.25 0.10 <br /> 100 127 0.125 0.05 <br /> LOQ 80.0 102 0.10 0.04 <br /> 50 64 0.0625 0.025 <br /> 25 32 0.03 0.0125 <br /> 20 25 0.025 0.010 <br /> 10 12.7 0.0125 0.005 <br /> 8 10.2 0.010 0.004 <br /> LOD 5.5 7 0.00675 0.0027 <br /> *Assumes 385 mm2 effective filter collection area,and field area=0.00785 mm2,for relatively"clean"(little <br /> particulate aside from fibers)filters. <br /> NIOSH Manual of Analytical Methods(NMAM),Fourth Edition <br />