Posted On: July 13, 2011 by GGCSMB&R

Use Of The Principles Of Safety Design Engineering In a New York Personal Injury Case Based On Negligent Product Design

By; Anthony Gair,

In personal injury cases predicated upon the negligent design of a product,(product liability cases), such as almost any type of machine which is to be used by people of varying training and skill it is imperative for the plaintiff’s attorney to understand the basics of machine design. This is crucial in New York where the plaintiff’s culpable conduct is a defense to a strict product liability action so that the percentage of fault for his injury may be, if not eliminated, reduced as much as possible. It is not enough for an attorney to simply ask a product design engineer at deposition how the product works. Such questions alone are pointless and will not result in a deposition which can be used to defeat a motion for summary judgment, or at trial, to impeach the product design engineer. As in any deposition the lawyer must ask himself what the purpose of the deposition is. Is it merely to gather information or is it to cross examine the witness so he will be pinned down at trial? In a product liability case in New York the plaintiff is allowed to serve extensive interrogatories. Hence if well drafted the plaintiff’s attorney will have most of the discovery needed for both deposition and trial. Hence it is submitted that the primary purpose of the deposition of a product design engineer is to cross examine him on the principles of design engineering. Similar to a deposition of a physician in a medical malpractice case where the plaintiff’s lawyer must know the medicine as well, if not better, then the physician the plaintiff’s lawyer must know the principles of design engineering as well as the design engineer. If one is not willing to learn this area there is no reason to undertake a complex product design defect case. The plaintiff’s lawyer must check the college and graduate school curriculum for the field of design engineering and read as many of the texts used in design engineering courses as possible.. If a lawyer is not willing to make this commitment he is better off referring the case to a specialist in product design defect cases. The following is a basic discussion of the principles of machine design.

Machine design is a sub-specialty of mechanical engineering. In designing machines, design engineers must take into consideration that a machine, will be used by people of varying intelligence, education and skill. “Human factors engineering, engineering psychology, and ergonomics are largely overlapping segments of a common area of interest: the analysis and design of the conditions affecting people operating in concert with machines”. 1

Ergonomics, or Human Factors Engineering and Design as it is commonly referred to in the United States, involves the consideration by the design engineer of human factors and characteristics when designing safety features into machines. The cardinal principal is that it is human nature to err, that is, people make mistakes. It is standard and accepted practice that the concept of human error be taken into consideration when designing a machine. A machine, must be designed to reduce, as much as is technologically feasible, without destroying the utility of the machine, foreseeable actions by the operator causing injury or death.

In designing a machine a hazard analysis must be done. From a design engineering standpoint a hazard is a condition that has the potential of causing or contributing to injury.

Danger in the context of safety design engineering theory means a higher probability of the risk of an identified hazard causing injury. Risk is the probability of being injured by an identified hazard.

When a design engineer has identified a foreseeable dangerous hazard, there is a safety design priority recognized by all design engineers with reference to preventing injury from the identified hazard which is a follows:

A. Design out the hazard if one can do so without destroying the ability of the machine to function or utility of the machine.

B. If an identified hazard cannot be designed out of the machine without destroying its ability to function or utility the next goal of the design engineer is to guard against it causing injury by incorporating guards or other safety devices.

C. The last alternative is that if one can’t design out the hazard because doing so would destroy the utility of the machine and one can’t guard against it by incorporating guards or safety devices, the last priority is to warn about it. It is the ethical responsibility of the design engineer for the machine to develop a safe functional design which eliminates or greatly reduces the potential for human error on the part of the machine operator causing injury to him self or others.

The following are sample questions that should be asked in a design defect case at the deposition of the design engineer who designed the product;




• Is it fair to say that before this machine was manufactured a hazard analysis was conducted?
• Can you explain to those of us who may not know what a hazard analysis is?
• What was your involvement in the hazard analysis with regard to this machine?
• Part of the hazard analysis would analyze among other things hazards associated with the use of the machine, is that right?
• Would you agree that from a design engineering standpoint a hazard is a condition that has the potential of causing or contributing to injury?
• Would you agree as a design engineer that once a hazardous condition is identified in a machine the first goal of the design engineer is to design out that hazard if such is possible without destroying the utility of the machine?
• Would you agree that as a design engineer that if an identified hazard cannot be designed out of a machine such as the subject machine without destroying its ability to function or its utility the next goal of the design engineer is to guard against it causing injury by incorporating guards or other types of safety devices, would you agree with that?
• Is it also fair to say that the last alternative is if you can't design out the hazard because doing so would destroy the ability of the machine to function or utility of the machine and you can't guard against it by incorporating safety devices or guards, then the last priority is you warn about it, correct?
• That is a priority, is that right?
• As a design engineer you are familiar with the concept of ergonomics, are you?
• In layman's terms that is what is known also as human factors, correct?
• In the course of your studies as a design engineer and safety design engineer, did you study the concept of ergonomics or human factors as it is also referred to?
• Is it fair to say that included in the field of ergonomics is the concept of human error?
• In designing a machine such as this machine, does a design engineer such as yourself take into consideration the fact that the machine is going to be used by people?
• When this machine was designed, you as the design engineer knew it would be used by people of varying degrees of intelligence, is that right?
• You knew, did you, that when this machine was designed it was going to be used by people with varying degrees of education, correct?
• I mean just as a general proposition as a design engineer when you design a machine and incorporate warnings and safety devices into the machine you don't do that for the highest common denominator, you do it for the lowest common denominator, don't you?
• As a design engineer when designing this machine, you knew, did you, that it was human nature to err?
• In designing this machine, you as a design engineer in incorporating safety devices including warnings and labeling into the machine took into consideration the fact that humans make mistakes, true?
• In designing this machine you as a design engineer in deciding what type of warnings to place on the machine itself and what type of warnings or instructions to put into the manual took into consideration the fact that humans make mistakes, true?
• Would you agree if we were all perfect and never made mistakes you wouldn't need any safety devices, guards or warnings on the machine, true?
• As a design engineer you design a product such as this machine with that in mind, that nobody is perfect and that people make mistakes, true?
• That is one of the cardinal principles of safety design engineering, isn't it?
• Is it fair to say that the reason safety devices are incorporated into the design of a machine is to prevent injury or death as a result of foreseeable actions by the operator of the machine?
• Is it fair to say that, from a design engineering standpoint, part of design engineering is anticipating the behavior of the machine operator and taking that into account in the design of the machine and its safety devices and warnings placed on the machine?
• As a design engineer, you're knowledgeable about the concept of risk, are you, as it relates to design engineering?
• By risk would you agree we mean the probability of being injured by an identifiable hazard?
• Would you agree that the term "Danger" in the context of design engineering theory, safety design engineering theory means a higher probability of the risk of a hazard, an identified hazard causing injury?
• And if the risk rises to a certain level then it becomes a dangerous condition
• Once you as a design engineer identify a dangerous condition on a machine, you as a design engineer then go back to the principles of safety design prioritization, correct?
• Basically that is, A, design out the hazard if you can do so without destroying the utility of the machine. B, if you can't design it out without destroying the utility of the machine, guard against it and incorporate safety devices to prevent the dangerous condition from causing injury or death. And, C, if you can't do either of those two, warn against it, Correct?
• That is the priority of the principles of safety design prioritization which you are well familiar with, aren't you?
• Would you agree as a design engineer that if you could prevent even one injury such as the one suffered by the plaintiff at a nominal cost that it would be a worthwhile thing to do?
• Do you agree that it is the ethical responsibility of a safety design engineer such as yourself to develop a safe functional machine design which eliminates or greatly reduces the potential for human error on the part of the operator causing injury to the operator?
• Can we agree that you as a safety design engineer want to make the machine as safe as technologically feasible without destroying the utility of the machine?
• Anything that you could do which was technologically feasible which could prevent injury to the operator without destroying the utility of the machine you would want to do, true?
• Isn't it correct that one of the basics of safety design engineering is to take into consideration unanticipated operator behavior in using the machine, I mean that is what a safety design engineer does, isn't it?
• Would you agree that at the time this machine was designed and manufactured, it was technologically feasible to have designed into the design of the machine without destroying the utility of the machine(the safety device you are claiming should have been used)?
• Would you agree that to assume perfect human performance can be achieved to avoid injury or death in the operation of a machine is unrealistic from a design engineering standpoint?
• Because that is the whole concept of human error, isn't it?
• You knew that when the machine was designed?
• So isn't it incumbent upon the design engineer who has done a safety analysis, who has identified hazards which can lead to serious injury or loss of life, to incorporate into the design of the machine devices which will prevent as much as possible operator error from causing injury or death?

1.Marks’ Standard Handbook for Mechanical Engineers, 9th ed., 1987, McGraw-Hill Book Company, at pps. 17-45.

For a sample of a portion of a deposition of a design engineer incorporating these principle see our prior post: NEW YORK PRODUCTS LIABILITY-DEFECTIVE PRODUCT DESIGN.

For more information on personal injury cases involving defective products contact the New York Personal Injury Lawyers at Gair, Gair, Conason, Steigman, Mackauf, Bloom&Rubinowitz.