Engineering Controls

Engineering controls are used to remove a hazard or place a barrier between the worker and the hazard. Well-designed engineering controls can be highly effective in protecting workers. The initial cost of engineering controls can be high, but over the longer term, operating costs are frequently lower, and in some instances, can provide a cost savings in other areas of the process. Examples of engineering controls include wet method cutting, mechanical ventilation, and dust collection systems.

Wet method cutting can reduce respirable dust by 85 percent. This method uses a drill with a water connection. This is particularly useful when cutting concrete, which has a high silica content.

If wet cutting is not practical, another option is to use a dust collection system. This method basically vacuums up the dust. However, these systems typically do not reduce exposure below permissible limits and additional controls still need to be implemented. A HEPA vacuum is an example of a dust collection system.

Mechanical ventilation is another engineering control to reduce chemical exposure. Ventilation can either be general (dilution) or local (exhaust) systems.

General ventilation forces fresh air into an area and dilutes contaminants. This provides a continual supply of fresh air. It is important to note that pure oxygen must never be used for ventilation purposes as it increases flammability risks. General ventilation works best when air contaminants are widely dispersed and toxicity and concentration levels are low. General ventilation can be simply achieved through the use of fans to blow fresh air inside the work site.

Local ventilation removes contaminated air. The contaminated air removed from the work space must be discharged into the open air, well clear of the source of intake air. Local ventilation works best when air contaminants are generated at a single source and there are high concentrations of toxins that need to be removed. Examples of local ventilation include exhaust hoods and fans set to pull or blow air out of the worksite.

To learn more about Construction Chemical Hazards visit our Construction Chemical Hazards & Toxic Substances Online Training web page.