HC 23

Controlling Silica Dust from Foundry Casting-Cleaning Operations

Exposure to respirable silica dust can lead to the development of silicosis, a debilitating and

potentially deadly lung disease. In foundry operations, workers who clean small castings made

from sand molds use various handheld chipping and grinding tools. If dust exposures are not

adequately controlled, workers breathe in high concentrations of respirable silica.

Studies conducted by the National Institute for Occupational Safety and Health (NIOSH) have

shown that excessive concentrations of respirable silica are produced when cleaning castings made

from sand molds. Use of the local exhaust ventilation (LEV) system described below significantly

reduced worker exposures to respirable dust by 59% to 77% for various cleaning tools. This system

may keep worker exposures to respirable silica below permissible limits and eliminate the need for

workers to wear respirators.

LOCAL EXHAUST VENTILATION (LEV) SYSTEM 

The LEV system consists of a downdraft ventilation booth outfitted with a turntable for

manipulating the castings. This system is designed to enclose and draw air contaminants

downward through a grate opening at the working surface of the table for cleaning small

castings. The table surface opening for this booth is approximately 5 ft long and 1.5 ft deep;

airflow rate for the system was about 5,600 ft3/min. This LEV system exceeds the minimum

recommended face capture velocity of 200 ft/min. The turntable allows the worker to have

easy access for cleaning multiple surfaces and directing the dusts generated from the tools

toward the grate opening, away from the breathing zone. (see ILLUSTRATIONS)

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Public Health Service

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health
Downdraft ventilated casting-cleaning workstation. Casting-cleaning turntable.

— call NIOSH* at 1-800-35-NIOSH (1-800-356-4674), or

— visit the NIOSH Homepage on the World Wide Web at

 http://www.cdc.gov/niosh/homepage.html

This document is in the public domain and may be freely copied or reprinted. NIOSH encourages all readers of

this HAZARD CONTROLS to make it available to all interested employers and workers.

ILLUSTRATIONS: VENTILATED WORKSTATION WITH TURNTABLE†

†U.S. Patent 5569074. For other than single use, contact NIOSH Technology Transfer Coordinator (513/841-4321)

For More Information

To obtain more free information about controlling this hazard or about other occupational safety and

health issues:

A technical

report has been published: An evaluation of a local exhaust ventilation control system for a foundry

casting-cleaning operation, Am Ind Hyg Assoc J (58): 354-358 (1997).

*NIOSH is the Federal agency responsible for conducting research and recommending measures for preventing workrelated illnesses and injuries. All HAZARD CONTROLS are based on research studies that show how worker

exposure to hazardous agents or activities can be significantly reduced.

Acknowledgments

The principal contributors to this publication are Michael G. Gressel, Rosmarie T. Hagedorn, and

Jerome P. Flesch.

December 1997 DHHS (NIOSH) Publication No. 98-106