Employing PtD as the first line of defense against control panel electrical hazards
Smarter electrical designs for industrial equipment control panels lower risk and improve safety. In 1979, the National Fire Protection Association (NFPA) released the first version of the NFPA 70E Standard for Electrical Safety in the Workplace. Today, Occupational Health and Safety Administration (OSHA) statistics show exposure to electrical hazards remain the sixth-most common cause of workplace fatalities overall and the third-most common cause in construction. Similarly, the Electrical Safety Foundation International (ESFI) found that from 2003-2017 the highest numbers for nonfatal electrical injuries were in construction and manufacturing.
Despite efforts to create awareness of electrical hazards and implement electrical safety programs that establish training and work procedures, electrical incidents continue to occur and workers are suffering the consequences. Prevention through design (PtD) can help workers with awareness and safety. The goal of PtD is to prevent workplace injuries through designs that limit human exposure and interaction with hazards as much as possible.
Best practice is to establish and verify an electrically safe work condition exists before performing work. Correctly de-energizing, verifying the absence of voltage, and complying with lockout/tagout (LOTO) requirements requires the proper training, qualifications, and procedures.
As plant operations evolve, personnel other than qualified electricians are interacting with electrical equipment when operating equipment. Tasks include updating firmware or programming, performing thermal scans, monitoring sensors, and performing non-electrical maintenance tasks. It is essential all personnel are aware of electrical hazards and these tasks are considered during the design phase so steps can be taken to mitigate potential exposure to electrical hazards.
Performing absence-of-voltage verification with a portable test instrument is dependent on human input, interaction, and interpretation. Human error can and does occur even for experienced personnel.
How can a worker safely perform these tasks in what’s potentially an electrically unsafe work environment? The need to maintain, monitor, and troubleshoot plant networks is increasing. This means it’s vital to use the best technology available to minimize direct access to potential electrical hazards.
Understanding the hierarchy of risk controls
Control engineers and equipment designers are the first line of defense against electrical hazards. Planning for safety throughout the equipment’s lifecycle needs to be top of mind when designing a workspace and selecting and installing equipment and safety technology.
A common challenge is: How do engineers develop a standardized solution that safeguards authorized personnel from the energy source in electrical enclosures?
PtD depends on understanding of the hierarchy of risk controls. The hierarchy ranks risk control measures from most to least effective:
- Elimination physically removes the hazard.
- Substitution replaces the hazard with something non-hazardous or minimizes the hazard.
- Engineering controls prevent access or act as a barrier between personnel and hazards.
- Administrative controls attempt to change the way people work through training, procedure, policy and signage.
- Personal protective equipment (PPE) can be effective in tandem with administrative controls, but does not eliminate the hazard.
The process of verifying absence of voltage in many organizations relies primarily on the lowest two tiers of the hierarchy, administrative controls (including LOTO procedures, training and devices) and PPE.
These methods are often the quickest to implement as they don’t require changes to existing equipment but are subject to human errors and may not be the most effective method to control exposure to hazards as a long-term solution. Between training, PPE replacement costs, and remaining potential for incidents, implementing these two tiers of controls alone may end up being more expensive in the long run than designing a workspace with advanced safety technology in from the start.
For example, PPE cannot prevent an electrical incident from happening; it only limits exposure. The effectiveness of administrative controls depends on the type of hazards and how consistently the controls are followed. Both leave significant room for human error.
Unfortunately, the most effective methods of risk control may not be feasible to implement. Eliminating electricity from an electrical enclosure is not an option. However, engineers can opt to implement substitutions that reduce shock hazards by replacing 120 V control circuits with 24 V. Exposed terminals also can be substituted with IP20-rated “finger-safe” terminals to prevent the risk of accidental contact with energized conductors.
Engineering controls don’t eliminate hazards but can isolate personnel from them and reduce risk to “as low as reasonably possible.” Mounted on the outside of a control panel, a data access port provides access to electrical outlets and control panels without the need for personnel to open the enclosure itself. In the case of network troubleshooting, data access ports (also referred to as programing port or service port) or remote network access allows personnel the ability to check or change program parameters without having to open the door to the electrical enclosure.
PtD technology advances
When it comes to electrical hazards, engineering controls are more effective and reliable than administrative controls and PPE alone. Active engineering controls may still require human interaction, but they are less susceptible to human error.
Data access ports, permanently mounted voltage indicators, voltage test portals, and automated absence of voltage testers are tools or technologies that can be used with the prevention through design methodology to help reduce exposure to electrical hazards in the workplace.
When de-energized work is required, automated absence-of-voltage testers (AVTs) can make the verification step of establishing an electrically-safe work condition safer and more efficient. By verifying the absence of voltage before the electrical equipment is even opened, automated testers reduce exposure to potential electrical hazards. Automating the process also makes it less susceptible to human error.
Realizing the benefits of employing PtD
Innovations like data access ports and automated AVTs are making it viable to complement existing control procedures or replace less-effective ones. These technologies prove that well-designed engineering controls protect workers without interfering with productivity. In fact, PtD can often improve productivity, save costs by making processes more efficient, and minimize direct and indirect costs that come with incidents that are a result of processes that rely more on human input.
Safety innovations need to move as fast as the manufacturing industry is. Administrative controls and PPE can only go so far when it comes to mitigating risk from electrical hazards. If safety professionals want to see electrical hazards drop off OSHA’s list of top risks, PtD and engineering controls will be key to making that happen.
Keywords: prevention through design, PtD, electrical safety
Prevention through design (PtD) can help workers with awareness and safety.
PtD depends on understanding of the hierarchy of risk controls and knowing what is the most and least effective.
PtD, if used correctly, can also improve productivity while minimizing direct and indirect costs.
How many tiers of the hierarchy of risk controls is your company following and what could you be doing better?