Forwarding WTC air monitoring scope for final review, Aug 2002

NYC 9/11 Public Portal Document

Pt. 763, Subpt. E. App. A 40 CFR Ch. I (7-1-00 Edition)

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

Count matrix as 1 structure.

no NOT OOCOT AS STOaCIOTES;

Fiber protrusion <5:1 Aspect Ratio No fiber protusion Fiber protrusion <0.5 microneter

— <0.5 microneter in length <5:1 Aspect Ratio

An Intersection is a non-parallel touching or (1) Fiber. A structure having a minimum crossing of fibers, with the projection having length greater than 0.5 pm and an aspect an aspect ratio of 5:1 or greater. Combina­ ratio (length to width) of 5:1 or greater and tions such as a matrix and cluster, matrix substantially parallel sides. Note the appear­ and bundle, or bundle and cluster are cat­ ance of the end of the fiber, i.e., whether it egorized by the dominant fiber quality—clus­ is flat, rounded or dovetailed, no intersec­ ter, bundle, and matrix, respectively. Sepa­ tions. rate categories will be maintained for fibers (2) Bundle. A structure composed of 3 or less than 5 pm and for fibers greater than or more fibers in a parallel arrangement with each fiber closer than one fiber diameter. equal to 5 pm in length. Not required, but (3) Cluster. At. structure with fibers in a ran­ useful, may be to record the fiber length in dom arrangement such that all fibers are I pm Intervals. (Identify each structure Intermixed and no single fiber Is Isolated morphologically and analyze it as it enters from the group: groupings must have more the “window”.) than 2 intersections.

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