Improving workflow reliability is paramount to the success of lean-based production operations. Unreliable workflow results from variability in performance. In the construction industry, sources of variability include late delivery of material and equipment, design errors, change orders, equipment breakdowns, tool malfunctions, improper crew utilization, labor strikes, and environmental effects. Another important source of variability, which is often overlooked in research and practice, is worker physical performance degradation. This degradation is caused by long term physical fatigue resulting from physically demanding work that remains ubiquitous in the construction industry. This research was motivated by the need to investigate the physical demands of construction work as an indirect source of workflow unreliability. Using work physiology principles, physiological measures of energy expenditure, including oxygen consumption and heart rate data, were collected for 18 construction laborers performing actual construction work. The results reveal that some workers routinely exceed one or more published guidelines for acceptable levels of physiological demands. The research points to the need to promote concepts of work physiology at the workplace to better the occupational safety and health of the construction workforce while simultaneously reducing performance variability and enabling lean conversion efforts.
Occupational Ergonomics, Work Physiology, Construction Safety