Presentation Abstract

Title: Asbestos Crane Friction Debris Study

Author: Cleo Thomas Driscoll

Presented at: AIHCE 2010, Denver, Colorado


Numerous studies have been conducted to determine the presence of asbestos fibers in automotive friction product wear debris. However, the literature regarding the asbestos content of crane friction product wear debris is lacking. Similar to automotive friction products, crane friction products have historically contained chrysotile asbestos. However, the configuration and operation of crane braking systems are different than automotive friction systems. Consequently, the purpose of this evaluation was to assess the presence or absence of asbestos fibers in the wear debris created by the friction components of cranes.


This study involved the examination and sampling of four cranes. To verify the presence or absence of asbestos in various friction components in the cranes, bulk samples including the boom, load, swing, and whip friction/brake materials were collected and analyzed by the polarized light microscopy (PLM). Following confirmation of asbestos in the friction components, wear debris samples were collected from friction surfaces using the ASTM Standard D-5755 vacuum method. Additionally, vacuum wipe samples from the operatorís cabs and three bulk debris samples from friction surfaces were collected.


PLM results of the friction components indicated that 19 of the 34 friction surfaces contained from 20% to 90% chrysotile asbestos.  The vacuum wear debris PLM sample analysis indicated that 38 of the 40 samples had no detectable asbestos (<1% wt).  Two vacuum debris samples obtained from a swing friction surface and a power down friction surface were each found to contain one chrysotile asbestos fiber. Additional testing of these two positive samples using PLM point count methodology and transmission electron microscopy (TEM) revealed no asbestos detected (<0.25% wt). 


The bulk asbestos in the debris from the friction products of the four cranes evaluated in this study was below the level deemed as an asbestos-containing material by EPA and OSHA. 

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