Can Sensors Identify Hazard Zones to Reduce Risk?

reduce risk

High risk industries such as construction have a clear focus to reduce risk. Currently, most safety inspections on construction sites are conducted by site managers as a visual activity, for example hazard identification, accident investigations, audits or when preparing job hazard analyses. Inspections are hampered by the ever changing environment where site conditions can change on a daily basis. Manual observation is inefficient, labor intensive, prone to error, inconsistent and costly.

Training in safety is the first step to reduce risk in high risk environments. Organisations should ensure their training regimes are thorough, on-point and as engaging as possible. Tap Into Safety can certainly help here, but real-time location systems have also been shown to help. They can monitor site activities and provide warnings and alerts when an employee enters a recognised and nominated hazard zone. The question that this post looks to answer is: can real-time location system monitoring, as a preventative measure, positively affect the safety performance of the employee? To answer this question we review recent research conducted on the US construction industry.

Zone based safety risk model

Over 20% of fatal accidents in the construction industry are associated with workers moving through high hazard zones at a construction site. These zone-based hazards include, but are not limited to, hazards associated with the physical conditions of a construction site. For example, unprotected large openings that account for 38% of all construction injuries in the US. In this study, workers were tracked using a real-time location system using sensors. The intent of the study was to develop a framework for an automated safety monitoring system to evaluate the movement of workers in and out of safety zones. Without such monitoring there is limited understanding of a worker’s actual movements on site. This procedure serves as an objective, quantitative method to evaluate safety performance determined by data collected on site.

The study developed a zone-based safety risk (ZBSR) model that aimed to mathematically process real-time location data to understand the behavior of workers. Zone-based hazard boundaries were established and defined as core hazard areas where the exposure to injury was high or envelope zones around the high risk area that workers should avoid entering. The degree of exposure, frequency of exposure and potential degree of injury were calculated. The core hazard was represented by a zone that must not be breached, and the hazard envelope was represented by a zone that should be protected.

The research involved two sets of field experiments to test the ZBSR model by quantifying the safety performance of a worker who was exposed often to hazardous areas. The size of each imminent hazard zone was specified by the site manager, based on the space and conditions of the hazard. The size of the envelope zone was chosen to be twice as large as that of the core hazard area that the safety manager considered reasonable. Based on these scenarios, the worker was tracked when they passed through a hazard zone and/or stayed in/out of a hazard zone. The tracking system collected the location information of the worker. The ZBSR model was applied to interpret and analyse the data in order to assess the safety performance of the worker in the form of a safety index.

A typical example of a workers movements in and around the nominated hazard zone was that the worker was:

  • in the safe area for 10 seconds
  • exposed to a low hazard for 10 seconds
  • exposed to a high hazard for 17 seconds
  • detected as remaining in the high hazard zone for 25 seconds
  • out of the high hazard zone for 28 seconds
  • back into the high hazard zone for 35 seconds
  • detected as remaining in the high hazard zone for 40 seconds
  • back in the safe zone.

The tracking of the worker in this example was very accurate and indeed showed movement in and out of hazardous zones. In using this method, construction organisations can develop a continuous job safety analysis, as well as a job-safety plan with real time data showing the behaviour of their workers.  Such a capability to quantify the safety performance of workers provides unprecedented levels of information to the site manager. This information can be useful for daily safety training as well as for real-time warnings to reduce risk.

But this example of a workers movements in and out of the high hazard zone raises several other questions:

  1. Was the worker aware of the hazard zones and that they shouldn’t be entering them?
  2. Was the work required within the high hazard zone to complete the task at hand and entering the zone was the only option?
  3. Was the worker taking a short cut through the high hazard zones and breaching safe operating procedures?
  4. Was the site layout designed in such a way that the worker had no choice but to enter high hazard zones on a regular basis?

Hazard perception training

Site managers and construction workers should be able to identify existing and predictable hazards at the site and should have the authority to take actions to eliminate such hazards. In recent years, monitoring of the safety conditions of workers has become more challenging with the increasing complexity of construction projects. Because of this trend in construction, safety managers are challenged with continuously monitoring and identifying incidents that may cause safety problems, and their ability to accomplish this task and to make proper and prompt decisions may be inadequate. The use of real-time location system using sensors to monitor worker movements provides interesting and insightful data. But in order to set up zone-based hazard areas the site manager must be able to identify each hazard, understand the risk and control methods to reduce risk.  The expectation that site managers automatically know what hazards are on site and understand how to reduce risk is flawed. Equally, in order to keep workers safe, employees must be trained in hazard awareness, pertinent to that site. This is where interactive hazard perception training is important.

Tap Into Safety offers interactive and engaging hazard perception training that is delivered via smart devices and online to reduce risk. We use real workplace photographic, panoramic examples that workers relate to because they show their work sites governed by the required regulations for their industry. Well-designed, visually pleasing, interactive, mobile and online solutions that include gamification, not only engage the user but encourage problem solving and knowledge retention. Our software has been designed to support workers with low literacy or minimal English language capabilities. We don’t use Power point, we use real workplace photographic, panoramic examples that workers relate to because they show their work sites. The training is delivered in 15 minute modules and can be even be accessed by sub-contractors with their competencies verified before they step foot on site. On the Tap Into Safety Platform there are 18 pre-built safety training modules, including many for construction workers. If you’d like to know more please contact us or click through to try a free online demo.


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