Solution Summary: Real-time Physiological Monitoring For Heat Strain in Workers
Heat-related incidents can be reduced on construction jobsites by an innovative administrative control: a connected platform that provides real-time physiological monitoring of workers. This cloud-based platform uses data collected from devices worn by workers. The devices are capable of monitoring heart and breathing rate, electrocardiogram (ECG), and skin temperature. It can also help detect falls on the job via a motion and tri-axis accelerometer to alert site personnel.
A real-time physiological monitoring platform, such as Black Ghost by Equivital (see figure 1), collects physiological data from the eq02+ LifeMonitor, which requires Bluetooth-connection to smartphones or radios. The data is then submitted via Wifi or radio transmission to the analytics software. Black Ghost provides live and retrospective data analysis. The software can accurately estimate core temperature with the capability to predict heat strain conditions 15 minutes ahead so that organizations can prevent rather than react. It also offers alerts in the systems that allow users to take timely action.
Figure 1. Real-time physiological monitoring via the Equivital Black Ghost platform (Photo courtesy of Equivital)
The eq02+ LifeMonitor contains a Sensor Electronic Module (SEM) that is worn in a chest harness (see figure 2) which is made of flexible stretch material and comes in 9 sizes to accommodate different body types. As the harness makes contact with the skin, it measures clinical grade cardiorespiratory, temperature and activity data that include:
1) Heart activity (ECG, Heart Rate, etc.)
2) Respiratory rate
3) Skin temperature
4) Galvanic skin response
6) Body position movement
7) Oxygen saturation
Figure 2. eq02+ LifeMonitor (Photo courtesy of Equivital)
The eq02+ LifeMonitor includes a medical grade infrared thermometer measuring skin temperature every 15 seconds and a high resolution tri-axis accelerometer providing data for activity monitoring and gait analysis. It can provide up to 48 hours of battery life from integral power supply. It also includes ancillary power packs and an 8GB memory which facilitates 50 days of continuous logging of physiological data.
Data is stored on the sensor and can be transmitted wirelessly for viewing on a mobile phone or computer. Medical and subject-identification data is encrypted using AEs256 to NIST standards.
The large and dynamic nature of construction jobsites makes maintaining site control a challenge, particularly complying with regulations and monitoring the safety of workers. Consequently, a real-time monitoring platform can reduce construction risks from a variety of hazards, including heat stress among workers and falls from elevation.
How Risks are Reduced:
While there is no federal standard for heat stress prevention, the American Conference of Governmental Industrial Hygienists (ACGIH) recommends a program of heat stress management. This includes acclimatization, early recognition of symptoms with appropriate first aid, recognition of personal risk factors, as well as carry-over effect from a previous day's exposure. In preventing heat stress and strain, the ACGIH recommends a threshold limit value (TLV) for body core temperature within +1oC of normal 37oC (98.6oF). In sum, Equivital is in the process of incorporating the ACGIH heat stress and strain TLV into the Black Ghost solution to facilitate users to comply with the TLV.
In addition, there is a free 2016 NIOSH Criteria Document “Occupational Exposure to Heat and Hot Environments" (https://www.cdc.gov/niosh/docs/2016-106/default.html) that references TLV and is similar in approach to the aforementioned ACGIH TLV.
Implementing a real-time monitoring platform to monitor workers can also improve safety through hazard identification and response when a fall from elevation is detected.
One study showed the advantage of using multiple physiological measures for enhancing physical exertion modeling to prevent physical fatigue development and its ill effects (Umer et al, 2020). Results from another study implied cardiorespiratory parameters and local skin temperature, in particular, were good surrogates for measuring physical fatigue (Anwer, Li, Antwi-Afari, Umer & Wong, 2020).
In addition, there has been work by Mike Schmoldt where he demonstrated real field applications that physiological monitoring was able to flag potential heat stroke risks where the heat stress monitoring of environmental conditions with WBGT measurements would not have predicted a problem.
It is recommended users follow all manufacturer guidelines and have proper training before using this device to ensure worker safety and compliance with applicable local, state or federal regulations.
Jean Christophe Le, MPH - CPWR The Center for Construction Research and Training
Bruce Lippy, CIH, PhD - CPWR The Center for Construction Research and Training
National Institute for Occupational Safety and Health DHHS (NIOSH) Publication Number 2016-106
To obtain information, visit Criteria for a Recommended Standard: Occupational Exposure to Heat and Hot Environments