Quantifying hazard exposure using real-time location data of construction workforce and equipment

Traditional risk-assessment methods typically evaluate accident probability, exposure frequency or duration, and consequence severity, respectively, and finally determine a quantitative risk score or a qualitative risk level. The assessment process is prospective and subjective. Changing and complex construction situations impede their practical and efficient application. To assess safety risk with regard to changing site conditions in an objective and efficient way, this study proposes a quantitative model for hazard exposure assessment based on real-time location data of construction workforce and equipment, collected by a location-based proximity warning system. In contrast with traditional risk-assessment methods, the model proposed in this study combines accident probability and hazard exposure duration into a single quantitative concept - hazard exposure amount. This concept takes into account the space factor as well as the time factor of construction activities. For ease of understanding, a hazard is analogized as a radiation source and the hazard exposure is then referred to as the radiation quantity received. The longer duration and closer proximity in which a person is exposed to a radiation (hazard), the more radiation the person receives (the higher risk to which the person is exposed). A trial study is described in which a proximity warning system was developed and used to demonstrate and test the model's capability of hazard exposure assessment. This shows that the system can provide safety officers with an ongoing and immediate means of comparing safety risk trends from worker, hazard, and project perspectives.