Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

The effect of a proposed change to fiber-counting rules in ASTM International Standard D7200-06.

Authors
Harper-M; Lee-EG; Harvey-B; Beard-M
Source
J Occup Environ Hyg 2007 May; 4(5):D42-D45
NIOSHTIC No.
20032077
Abstract
Asbestos is a form of certain serpentine or amphibole minerals that has crystallized in a particular habit known as asbestiform. Amphibole minerals are often encountered in metamorphic geological environments, but the majority will not have crystallized in the asbestiform habit. Thus, ore deposits in these environments may include coarsely crystalline amphiboles that can produce cleavage fragments when the rocks are crushed. These fragments may meet morphological criteria that cause them to be designated as "fibers" but without their being asbestiform per se. In an attempt to distinguish cleavage fragments from asbestiform fibers, the American Society for Testing and Materials (ASTM) International Standard D7200-06(2) includes a procedure for determining whether the particles observable under the phase contrast microscope that meet a morphological definition of a fiber are likely to be asbestiform fibers or cleavage fragments. (The morphological definition of a fiber is that described in the National Institute for Occupational Safety and Health [NIOSH] 7400 "A" counting rules, i.e., >5 mu/m in length and with aspect ratio [length:width] greater than or equal to 3:1). Under ASTM D7200, any particle meeting the definition of a fiber that is curved or has any morphology that suggests that it is a bundle of fibrils is automatically assigned to a class of particles (Class 1) defined as potentially asbestiform, whatever its actual dimensions.
Keywords
Environmental-contamination; Environmental-exposure; Environmental-hazards; Fibrous-bodies; Molecular-structure; Particulate-dust; Particulates; Work-environment; Analytical-processes; Analytical-methods
Contact
Shih-Houng Young, PhD, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, 1095 Willowdale Road (M/S 2015), Morgantown, WV 26505
CODEN
JOEHA2
Publication Date
20070501
Document Type
Journal Article
Email Address
sby5@cdc.gov
Editors
Ashley-K
Fiscal Year
2007
NTIS Accession No.
NTIS Price
Issue of Publication
5
ISSN
1545-9624
NIOSH Division
HELD
Source Name
Journal of Occupational and Environmental Hygiene
State
WV
TOP