This chapter covers the engineering methods widely used to minimize adverse effects on health, well‐being, comfort and performance at the workplace and in the community. Major attention will be given to controls for chemical airborne contaminants, although many of the control principles are also applicable to biological and physical hazards. Brief case studies illustrate the applications of the techniques. The target for control may be a hand tool, a piece of equipment or a device, an integrated manufacturing process such as an electroplating line, or a complete manufacturing facility in a dedicated building such as a foundry.
The critical zones of contaminant generation, dispersion, and exposure are shown. Ideally the goal is to design each element of the process to eliminate contaminant generation. If it is impossible to achieve this goal and a contaminant is generated, the second defense is to prevent its dispersal in the workplace. Finally, if these defenses fail and the material released from the operation results in worker exposure, the back‐up control is collection of the air containing the contaminant by exhaust ventilation. Frequently the contaminant is removed from the exhaust air stream by air cleaning before returning the air to the workplace or the general environment. Unfortunately, in the United States little emphasis is often given to the prevention of contaminant generation and release and we rely on ventilation as a principal remedy. In this chapter the author confirms the importance of ventilation but emphasis will be placed on the primary controls associated with process and material design to minimize generation and release of the contaminant.
The Occupational Safety and Health Administration (OSHA) considers engineering controls as any modification of plant, equipment, processes or materials to reduce employees' exposure to toxic materials and harmful physical agents. Authors have used a variety of approaches to classify the various engineering control techniques. These approaches provide a useful outline for discussion and act as checklists to ensure a comprehensive review.
In this chapter, engineering controls include all techniques except personal protective devices and administrative controls, those changes made in the work schedule to reduce the time weighted average exposure of the worker.