7 Safety In Engineering Design

RESPONSIBILITIES OF ENGINEERS                                                                                                              

As the act of engineering often results in a device, structure, or system being built, the engineers are obligated to consider the safety conditions of not only the product, but also the persons working on the product and the end user. Frameworks and methods of design and production have been developed to consider safety.  Within these frameworks exist rules and regulations that have been put in place to reduce accidents during construction and operation, and to optimize for future improvements, but at the end of the day,  it is still up to the engineer to work within, and often beyond, these frameworks and safeguard against foreseen and potentially unforeseen circumstances by following these codes and standards.

HAZARD RECOGNITION AND CONTROL                                                                                                     

Hazards, regardless of the field, will always need to be eliminated or mitigated. Thus, there exists an entire field of research devoted to the methods surrounding hazard identigication and elimination, known as risk management. “Hazards” are the dangers themselves, be they chemical, physical, or psychosocial, while the term “risk” entails the likelihood of these hazards affecting the workers or consumers. In general, the many frameworks used in risk management utilize a series of checklists to identify hazards and decrease risk. A very basic risk management procedure is shown below [1]:

1. Identify and assess the hazard.
2. Prevent or eliminate the hazard.
3. If elimination is not possible, treat the hazard as a “source” of harm that may flow to the user. This is known as the “source-path-receiver” analysis, and identifies the 3 main points where action should be taken to minimize hazards.
4. If all steps fail, perform damage control by recalling unsafe devices, notifying people of danger, assisting the injured, and so on.

Identifying and Assessing Hazards

According to the US Department of Occupational Safety and Health, hazards can often be broken down into a few key categories [6].

• Chemical Hazards – Volatile materials, materials that have low exposure limits, or chemicals used in large quantities or in poorly ventilated spaces.
• Physical Hazards – Excessive noise or vibrations, extreme temperatures, or sources of radiation.
• Biological Hazards – Sources of disease, molds, toxins, or any animal materials capable of causing allergic reactions or asthma.
• Ergonomic Hazards – Activities requiring heavy lifting, working above shoulder height, repetitive motions, or tasks with significant vibrations.
• Psychosocial Hazards – Stressful work environments, violent behaviours, etc. [5]

To effectively identify and categorize hazards, one must consider whether or not the product itself is safe, whether the individuals building and working on the product are safe, and one must be mindful of the means by which the end user may incorrectly use the product or accidentally harm themselves with it.

In general, designing an item for a wider audience is more difficult, as the needs of the users vary more, and their mental and physical abilities occur over a very wide spectrum. Due to this fact, minimum skill level requirements must not be overestimated, as users with different needs or abilities will all be interacting with your product in different ways.

Additionally, the device itself may cause issues. You must anticipate common errors people will make, and common modes of failure for your product to minimize damages if the worst does occur. Health and safety evaluations of your product should also be undertaken as a part of a design review, ensuring that obvious hazards are avoided or warned against, and that if a lawsuit should occur, you have proof that you did your best to mitigate harm.

Hazard Prevention/Control

Workplace hazard prevention is a very involved process, with its own hierarchy. At best, all workplace hazards should be eliminated, and at the very least, workers should always be equipped with the appropriate Personal Protective Equipment (PPE) for their task.

Consumer hazard prevention can be as simple as designing your product with safety in mind, and providing adequate warnings and labels for misuse. Warnings should always be affixed in highly visible places, and be in bright colours so as to not be overlooked. Ideally, they should also be permanently affixed to your product in some way. Pictorial warnings have also been shown to be more effective than written warnings, so you should be aware and make use of applicable common labels. These labels are often regulated and recommended by standards institutes such as the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO) [1].

•    DANGER  : The danger sign warns of extreme or imminent risk of death or injury. The lettering is white on a red background.
•  WARNING : The warning sign denotes a specific potential hazard that could result in injury or death. This panel has black lettering on an orange background.
•  CAUTION  : The caution sign is used to warn of risks or unsafe practices that could result in minor or moderate injury. The panel has black lettering on a yellow background.

Hazard Elimination

Hazard elimination is difficult in many cases. Job sites often necessitate some of danger, as variables such as temperature, humidity, sounds and vibrations can be very difficult, and very expensive, to keep at optimal levels. These variables are stressors, or causes of stress, which cause strain on workers, affecting their health and well-being. To eliminate as many hazards as possible, and safeguard against the rest, checklists are often used to ensure safe working and operating conditions.

Additionally, there are three main points of hazard prevention as mentioned above. Source control ensures that the hazard itself is isolated by capturing, guarding, enclosing, or insulating it.  Path control increases the distance between the source and the user, which is particularly useful for minimizing variables such as noise or electrical hazards. Finally, user control ensures that all workers or users wear adequate personal protective equipment (PPE), and have schedules to minimize exposure to unavoidable hazards, such as noise, light, or radiation.

Damage Control

If all else fails, product recalls can be a good way to minimize further hazard exposure. This can give you the opportunity to evaluate the device to see what went wrong, and thus learn from the experience. Recalls should be your last line of defense, as they often indicate something has already gone wrong, and thus recalls may be instituted for one or more of five principal reasons:

1. Analysis reveals the presence of a potential hazard.
2. Reports indicate unsafe conditions, unsafe incidents, or unsafe product characteristics.
3. Incidents reveal a previously unforeseen product deficiency.
4. Government codes or standards have been violated.
5. The product does not live up to its claims of safety.

RISK MANAGEMENT                                                                                                                                         

Risk management often requires an increase in capital. Increased research and development, better equipment, more worker rotations and the need for more complex processes or devices all require money. Engineers must balance hazard mitigation with factors such as monetary constrains, and thus risk management is a very complex topic.

Risk management is a function of actual or expected costs, and the likelihood that a failure event will occur. Thus, there are three main stages of risk management [1]:

• Risk Analysis: This is the process of identifying hazards or the consequences of hazards. To deduce the likelihood of these events, engineers must use logic, deduction, and mathematics, ensuring that risk analysis is rational and objective.
• Risk Evaluation: The evaluation of risks tends to be a little less objective than their assessment. The risks assessed in the previous step must be eliminated or minimized, in order to have probabilities of dangerous events below a given threshold. This threshold is based on many factors, such as the perception of risk and the cost of mitigation, and thus engineers often have to make the call of determining how safe is “safe enough”.
• Management Decisions: Once all the risks have been identified and evaluated, it is the job of management to implement the elimination or mitigation strategies. This involves monitoring these potential sources of danger, reviewing the actions taken and their effects, and revising these activities if and when necessary.

REFERENCES                                                                                                                                                      

[5] Canadian Centre for Occupational Health and Safety, “Hazard and Risk”, May 4th, 2018,
https://www.ccohs.ca/oshanswers/hsprograms/hazard/hazard_identification.html (Accessed September 2nd, 2023).

[6] Occupational Health and Safety Administration, “Hazard Identification and Assessment”, US Department of Labor,
https://www.osha.gov/safety-management/hazard-Identification (Accessed September 2nd, 2023).

[7] Engineers Canada, “Risk Management Process”,
https://engineerscanada.ca/public-guideline-on-risk-management#-risk-management-process (Accessed September 2nd, 2023).