Return to Sender: System Maintenance, Reverse Logistics, and Hazardous Materials Transportation by Scott Gunderson, Portland, Oregon   Page:  1 | 2 | 3 Systems extend across time through their life-cycle stages of design, production, operation and retirement. Within the scope of operation, system maintenance can represent an extension across space through the logistics functions of component removal for failure analysis, repair or replacement. Service occurring away from the site of the owner or operator extends system boundaries with the addition of reverse logistics. Peters and Peters introduce expansion of system safety to non-traditional disciplines [Ref. 6]. System maintenance with reverse logistics provides a similar opportunity for system safety expansion, not only by drawing new boundaries to include off-site service, but also through the analysis of risks associated with residual contamination and hazardous materials transportation. Reverse logistics challenges the perception of any system as confined to its hardware/software architecture. Fleischmann defines reverse logistics in the context of "the growing importance of material flows opposite to the traditional supply chain direction," and includes return transportation for reuse, remanufacture, repair, recycle or disposal. Much of this is derived from design for environment metrics and increasing supplier take-back and recovery obligations for organizations conducting business in the European Union [Ref. 4]. Successful implementation of reverse logistics activities requires attention to design for disassembly for safe and effective system maintenance [Ref. 2]. Accessibility is a significant element of this design consideration, and Kumar and Crocker cite an aerospace example with an incredible requirement for one maintenance technician to hold another upside down by the ankles to reach an internal disconnection point [Ref. 5]. Aside from the human factors and safety issues for the technicians performing this task, additional issues include increased maintenance time, decreased availability, excessive handling, and potential for system damage and reduced reliability upon final return to service [Ref. 3].   "Kumar and Crocker cite an aerospace example with an incredible requirement for one maintenance technician to hold another upside down by the ankles to reach an internal disconnection point" Potential hazardous materials contamination further complicates both maintenance and reverse logistics. The semiconductor industry, which uses both a large quantity and variety of hazardous materials in the manufacture of its products, has a number of system safety elements in its equipment design and operation standard [Ref. 8]. Other standards for decontamination and disposal provide guidance on designing for the end of the system life cycle [Refs. 9, 10]. But in spite of these standards, the challenges of contaminated legacy systems continue to present both frustrations and learning experiences, and semiconductor industry representatives continue to revisit this issue for lessons learned and opportunities for improvement [Ref. 7]. Such lessons provide cases for risk analysis and design initiatives to prevent such liabilities, and reduce total cost of ownership and probability of accidents. Risk Analysis A simple fault tree illustrates the risk associated with reverse logistics and hazardous materials contamination (see Figure 1). If starting with contaminated material, then shipping "as is" may only take place with trained personnel qualified to perform the evaluation, documentation and packaging necessary for a regulated hazardous materials shipment [Ref. 1]. Additionally, new transportation security requirements have increased the compliance burden for both shippers and carriers of hazardous materials [Refs. 11, 12]. Mistakes in the initial shipping sequence, or later during transportation (such as dropped packages or other handling errors), may result in hazardous materials release in transit, causing delay, human harm, third-party liability and potentially large regulatory fines. The scope of this fault tree and this article presumes adequate evaluation and legal shipment. The worst-case scenarios of intentionally mislabeled and undocumented "stealth" shipments, or accidentally unlabeled and unrecognized shipments (such as the oxidizers that initiated the 1996 Valujet crash in Florida) are outside the scope of this analysis [Ref. 14]. NEXT PAGE »