Hyatt Regency Walkway Collapse

1. Hyatt Regency Walkway Collapse Presentation by William J. Frey

2. Agenda • Case Narrative • STS Table • Case Chronology • Key Decision Point • Ethical Issue—Responsible Design • To Engineer is Human (Video by Petroski) • Code of Ethics Issues

3. Case Narrative • On July 17, 1981, the second and fourth story walkways of the Kansas City Hyatt Regency Hotel collapsed killing 114 people and seriously injuring an additional 200. • Cause: • “A deviation in the design in the way the rods connected the lower skywalk to the upper and the upper to the ceiling of the atrium was clearly described and zeroed in on as the ultimate cause of the accident.” Petroski: 86

4. Case Narrative • Warning Signs • The Atrium ceiling collapsed during construction; but a study carried out by an independent engineering found nothing wrong with the skywalk • Workers carrying loaded wheel barrows across the skywalk complained about excess vibration and swaying • Petroski • “After twenty months of investigation, the U.S. attorney and the Jackson County, Missouri, prosecutor announced jointly that they had found no evidence that either a federal or state crime was committed…” • However in an investigation carried out by the attorney general of Missouri… • Duncan, Gillium, and GCE International Inc. were found guilty of “gross negligence, misconduct and unprofessional conduct in the practice of engineering.”

5. Chronology (Adopted from TAMU)

6. Chronology

7. Chronology

9. Concepts related to Safety and Risk Risk Assessment Risk Communication Risk Perception Risk Management

10. Safety • “A thing is safe if, were its risks fully known, those risks would be judged acceptable in light of settled value principles.” (Martin/Schinzinger, Engineering Ethics, 108) • Safety and risk are different sides of the same coin • One is defined in terms of the other • “Settled value principles” makes safety a matter of public policy. Government plays a role. So does business. Most importantly, so do members of the public

11. Public • “those persons whose lack of information, technical knowledge, or time for deliberation renders them more or less vulnerable to the powers an engineer wields on behalf of his client or employer” • Michael Davis. Thinking Like An Engineer • The public is in an especially vulnerable position. They stand subject to the risk. But they do not participate in the project that generates the risk • The public has the right to free and informed consent. • This right is vulnerable if risk information does not get to them, if the risk information is too complicated for them to appreciate, or no provisions have been taken to include them in the collective risk acceptability (=safety) decision.

12. Risk • The other side of the coin • Risk and safety are correlative and defined in terms of one another • “A risk is the potential that something unwanted and harmful may occur.” (MS 108) • Risk has four dimensions (assessment, management, perception, and communication) • Since risk is the probability of harm and probability implies uncertainty (lack of complete knowledge), the ethics of risk lies in how this uncertainty is communicated and distributed. • For example, does a government regulatory agency approve a product unless it is proven harmful…. • Or does it withhold approval from a product until it is proven completely safe. • In the first, the burden of uncertainty falls on the public exposed to risk, in the second on the manufacturer who can’t reap benefits from selling the uncertainly risky product.

13. Risk Assessment • The scientific and exact process of determining the degree of risk • Animal Bioassays • Animals exposed to risk fact at intense level for short period of time • Projection from animal physiology to human physiology and from short term/intense exposure to long term/less intense exposure • Epidemological Studies • Comparison between populations exposed to risk and populations not exposed to risk • Search for significantly higher risk ratio. Three-to-one not generally significant. Six-to-one is significant • Ethics of Risk • Since there is uncertainty in risk assessment, an ethical issue arises as to how that uncertainty is distributed

14. Risk Assessment in Engineering • Fault Tree • “a diagram of the possible ways in which a malfunction or accident can occur.” • “enable an engineer to analyze systematically the various failure modes attendant to an engineering project” • Determining why a car won’t start by considering different failure modes • Harris, E., Pritchard, M., and Rabins, M. (2005). Engineering Ethics: Concepts and Cases . Thompson: 156

15. Risk Assessment in Engineering • Faiure Mode • “way in which a structure, mechanism, or process can function.” • Event Tree Analysis • “reason forward from hypothetical events to determine what might have led to the final event” • Reasoning from pipe break in nuclear reactor to possible outcomes (release of radiation) • Harris, E., Pritchard, M., and Rabins, M. (2005). Engineering Ethics: Concepts and Cases . Thompson: 157

16. Limitations in Risk Assessment • Cannot predict all possible failure modes • Human error is also difficult to predict (See Reason in Human Error for a possible account) • Probabilities assigned are largely a matter of guesswork • “We can never be sure we have all of the possible initiating events…. • Harris, E., Pritchard, M., and Rabins, M. (2005). Engineering Ethics: Concepts and Cases . Thompson: 157-8

17. Different Kinds of Accident • Normal Accidents (Perrow) • Happens in tightly coupled systems • Leads to non-linear causality • Small failure proves difficult to isolate; spreads out to create other failures; these cascade to produced catastrophe • Complexity of system makes it difficult to predict accident and assess risk • Ladd calls these “loss of control” accidents • John Ladd. Bhopal Article

18. Human Error • Reason treats accidents as pathogens that are latent in a complex system • When circumstances are right, a configuration of events creates an opportunity for the pathogen to emerge • Reason argues that accidents come from human cognitive procedures that usually work for the best

19. Risk Communication • Results of risk assessment are technical and subject to different interpretations • Public has a right to informed consent vis a vis risk • To consent to take a risk (or withhold consent) they must understand the risk and be able to make a coherent consent decision • This raises issues in risk communication • Clear communication • Comprehensive communication (not leaving out anything significant) • Communication that takes into account the perspective from which the public will perceive the risk

20. Risk Perception • The public perceives risk according to a clear perspective • This renders risk perception rational because predictable (to a certain extent) • Factors which influence public perception of a risk’s acceptability • Voluntariness • Expected benefits • Control over risk • Minimal dread factor • Minimal unknown factor

21. Risk Management • Political process of determining if a certain degree of risk is acceptable according to a community’s settled value principles • Value principles are identified via a process of deliberative democracy which respect the meta-norms of reciprocity, publicity, and accountability • Community’s identify small scale project for experimental analysis • These validate settled values • These also help to determine if larger scale action is acceptable

22. Resources • Hyatt Regency Kansas City Walkway Collapse" Online Ethics Center for Engineering 11/24/2010 National Academy of Engineering Accessed: Thursday, December 16, 2010 <www.onlineethics.org/Resources/Cases/24338.aspx> • Henry Petroski (1985). To Engineer is Human: The Role of Failure in Successful Design. St. Martin’s Press: 85-97.