from the phrase of the poet, Alexander Pope, “to err is human, to forgive is divine” (Alexander Pope: 1688–1744), the PtD version might read as “to err is human; to prevent by design is divine.” Fallibility is an inherent, ever‐present element of the human condition. The potential for human error and mistakes during interactions between system elements – humans, tools, machinery, software, materials, procedures, and the work environment – always exists. However, when overly complex or error‐prone elements exist in workplace systems, the likelihood of errors increase (1). In other words, poor or confusing designs lead to potential error‐traps, which in turn lead to incidents, injuries, and even fatalities. The practice of PtD must include designing for error‐free work using human factors engineering and ergonomics principles.
2 THE RELATIONSHIP BETWEEN FATALITIES AND UNSAFE DESIGN
For the practice of OSH, a major concern remains the number of workplace fatalities each year. Over the years, incident rates have been on a decline, however, fatality rates have flattened and slightly increased. Bureau of Labor Statistics (2) data indicate 5190 workers died from occupational injuries in 2016, a 7% increase over 2015, and the highest since 2008.
Studies indicate a causal relationship may exist between workplace fatalities and unsafe workplace designs. In Australia, a 2014 study examined the relationship between occupational fatalities and unsafe design of machinery, equipment, and facilities over a six‐year period. The study found that 12% of the fatalities were directly caused by unsafe design or design‐related factors, while 24% were possibly caused by design‐related factors (3). Fatalities and serious incidents (FSIs) that occur in the construction industry can be directly linked to the level of prevention incorporated into the planning and design of the project (4). According to studies of fatalities in construction, over 40% were connected to the design‐related factors (5). For occupational FSIs to be effectively and consistently reduced, prevention and safety must be designed into workplace systems and methods. This requires the use of risk avoidance, elimination, and substitution, the most effective risk treatment options in the PtD hierarchy of controls, to be incorporated into design and redesign efforts. For future FSIs to be avoided or reduced, the workplace systems and conditions that present hazards and risks that make FSIs possible must be designed out.
3 THE DEVELOPMENT OF PD
Avoidance of hazards and risk, the top of the hierarchy, should always be considered the first in the practice of OSH. Fundamentally, avoiding a problem rather than accepting it and managing around it, makes good sense from an OSH as well as a business standpoint. Systems are designed and brought into the workplace, bringing with them embedded elements, some of which are hazard‐risks. These embedded hazards are present in the system for its entire lifecycle. When efforts are made to anticipate, identify, assess, and control hazards and their risk during design, the resulting system is improved in a number of ways. This concept is known as PtD.
Prevention through design, PtD as it is known, can be traced back to the 1970s in certain industries including automotive as a result of the newly enacted Occupational Health and Safety Administration (OSHA) safety regulations. In an effort to meet regulations, process engineers began exploring ways of designing in safety to improve machine designs, safeguarding, and noise reduction (6). Efforts to design in safety continued in certain industries, however, inconsistently. Then, in 1994, a Position Paper was released by the American Society of Safety Engineers–American Society of Safety Professionals (ASSE–ASSP now) to promote the gathering of knowledge and applications of “Designing for Safety” as it was originally called. In 1995, the National Safety Council established a 10‐year effort, the Institute for Safety through Design. This Institute fulfilled a need for integrating hazard analysis and risk assessment into the conceptual stages of design with the purpose of avoiding and eliminating hazards and risks. In 1999, the Institute published the landmark book, “Safety through Design” edited by Fred Manuele and Wayne Christensen. It provided real‐life examples from 20 contributing authors of PtD and design safety efforts from various industries and presented the benefits derived. The work and research conducted through the Institute and the National Safety Council were to be the foundation of the current PtD concepts and practices.
In 2007, after the 10‐year National Safety Council effort concluded, leaders at the National Institute for Occupational Safety and Health (NIOSH) invited all stakeholders, including the authors of “Safety through Design,” to continue the effort and join with them in a National Initiative called “PtD” (7). As part of the PtD initiative, over three hundred representatives representing ten different industry sectors met, culminating in “The Plan for the National Initiative” in 2009 (www.cdc.gov/niosh/docs/2011-121). Goals in the plan are organized into education, research, practice, and policy. A progress report was published in 2014, “The State of the National Initiative on PtD” (www.cdc.gov/niosh/docs/2014-123). Other PtD efforts at NIOSH can be found at the PtD website, www.cdc.gov/niosh/topics/ptd.
A key policy advance was the American National Standards Institute (ANSI)/ASSP Z590.3 PtD consensus standard, discussed in detail in the remainder of this chapter. Important policy guidance was also needed in the burgeoning “green” industry. In 2009, NIOSH held a “Making Green Jobs Safe” PtD workshop, where, in his first official speech as OSHA administrator, Dr. David Michaels, asked: “How sustainable is dangerous technology?”
After four years of collaboration with the NIOSH PtD and Construction programs, the U.S. Green Building Council (USGBC) published, in 2015, a Leadership in Energy and Environmental Design (LEED) PtD pilot credit for building certifications (www.usgbc.org/articles/new-leed-pilot-credit-prevention-through-design). The pilot credit, developed in partnership with NIOSH, prompts the use of PtD methods to design out worker hazards for both the construction phase and operations and maintenance phase of a building's life cycle. Similar to the publishing of the ANSI/ASSP Z590.3 PtD Standard, this PtD LEED credit is considered a major strategic advance for PtD, as LEED criteria are used throughout the United States, and around the world.
Returning to the first of the key policy advances for PtD, in 2011, the first U.S. standard to address the need for incorporating safety into design was published – ANSI/ASSP Z590.3‐2011 PtD – Guidelines for Addressing Occupational Hazards and Risks in Design and Redesign Processes standard. ANSI/ASSP Z590.3‐2011 (R2016), or the PtD standard as it is sometimes called, provides guidance for assessing and treating risk throughout the life cycle of a system. Z590.3 provides an operational risk management model that balances environmental, safety, and health goals over the life span of a system as shown in Figure 1.
Workplace systems, facilities, equipment, and products all have a defined life cycle in which risks may change. As shown in Figure 2, these phases, changes, and events of a system's life cycle represent “triggers” for identifying, assessing, and treating risks to achieve and maintain acceptable risk.
As stated in Z590.3, an important goal of the standard is to educate designers, manufacturers, OSH professionals, business leaders, and workers in PtD principles and encourage their application in design and redesign efforts.
An important concept in PtD is the “avoidance” of risk in designs. The ANSI Z590.3 PtD hierarchy of controls model, shown in Figure 3, promotes the use of higher‐level controls – avoidance, elimination, substitution, and engineering – in the design and redesign phases. These higher‐level controls are considered the most effective in reducing risk and more economical than lower‐level controls such as administrative and personal protective equipment (PPE). This concept is logical, however, in practice, few organizations have fully taken advantage of pre‐operational risk management