Forwarding WTC air monitoring scope for final review, Aug 2002

NYC 9/11 Public Portal Document

Environmental Protection Agency Pt. 763, Subpt. E, App. A

count clusters as 1 structure; fibers having greater than or equal to 3 intersections.

Count matrix as 1 structure.

no NOT OOUOT as STROCTORES:

Fiber protrusion <5:1 aspect Ratio No fiber protusion Fiber protrusion <0.5 micrcireter

------ <0.5 micrcmeter in length _ <5:1 aspect Ratio

1. Fiber. A structure having a minimum from the group. Groupings must have more length greater than or equal to 0.5 gm and an than two Intersections. aspect ratio (length to width) of 5:1 or great­ Iv. Matrix. Fiber or fibers with one end free er and substantially parallel sides. Note the and the other end embedded in or hidden by appearance of the end of the fiber, l.e., a particulate. The exposed fiber must meet whether it is flat, rounded or dovetailed. the fiber definition. 11. Bundle. A structure composed of three b. Separate categories will be maintained or more fibers In a parallel arrangement for fibers less than 5 gm and for fibers equal with each fiber closer than one fiber diame­ to or greater than 5 gm in length. ter. c. Record NSD when no structures are de­ ill. Cluster. A structure with fibers in a tected in the field. random arrangement such that all fibers are d. Visual Identification of electron diffrac­ Intermixed and no single fiber is Isolated tion (ED) patterns is required for each asbes­ tos structure counted which would cause the

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NYC-WTC_000139292