Details:

Alternative Title:
Ann Occup Hyg
Personal Author:
Echt, Alan ; Mead, Kenneth
Echt, Alan ; Mead, Kenneth Less -
Description:
Purpose

To assess the effectiveness of local exhaust ventilation to control respirable crystalline silica exposures to acceptable levels during concrete dowel drilling.

Approach

Personal breathing zone samples for respirable dust and crystalline silica were collected while laborers drilled holes 3.5 cm diameter by 36 cm deep in a concrete slab using a single-drill slab-riding dowel drill equipped with local exhaust ventilation. Data were collected on air flow, weather, and productivity.

Results

All respirable dust samples were below the 90 µg detection limit which, when combined with the largest sample volume, resulted in a minimum detectable concentration of 0.31 mg m−3. This occurred in a 32-min sample collected when 27 holes were drilled. Quartz was only detected in one air sample; 0.09 mg m−3 of quartz was found on an 8-min sample collected during a drill maintenance task. The minimum detectable concentration for quartz in personal air samples collected while drilling was performed was 0.02 mg m−3. The average number of holes drilled during each drilling sample was 23. Over the course of the 2-day study, air flow measured at the dust collector decreased from 2.2 to 1.7 m3 s−1.

Conclusions

The dust control performed well under the conditions of this test. The initial duct velocity with a clean filter was sufficient to prevent settling, but gradually fell below the recommended value to prevent dust from settling in the duct. The practice of raising the drill between each hole may have prevented the dust from settling in the duct. A slightly higher flow rate and an improved duct design would prevent settling without regard to the position of the drill.


Subjects:
[+]
Air Pollutants, Occupational Article Concrete Construction Industry Construction Materials Drilling Dust Environmental Monitoring Humans Inhalation Exposure Occupational Exposure Quartz Respirable Silica Silicon Dioxide Ventilation
Source:
Ann Occup Hyg. 60(4):519-524.
Pubmed ID:
26826033
Pubmed Central ID:
PMC4901878
Document Type:
Journal Article
Funding:
CC999999/Intramural CDC HHS/United States
Collection(s):
CDC Public Access
Main Document Checksum:
[+]
urn:sha256:57e03a83653c4a00911b97a1bb2460d9fa3fa786679cb752636bceb7b0369e72
Download URL:
https://stacks.cdc.gov/view/cdc/39860/cdc_39860_DS1.pdf
File Type:

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