Investigating the Utility of Global Positioning System (GPS) Technology to Mitigate the Carbon Monoxide (CO) Hazard Associated with Portable Generators – Proof of Concept Demonstration

Sciences (ESFS) staff has conducted a limited, exploratory exercise to demonstrate the feasibility of using Global Positioning System (GPS) technology to distinguish indoor and outdoor environments, with the intent of shutting down portable generator operation when a generator is used indoors. Through a series of experiments, ESFS staff demonstrated that a modified, off-the-shelf, commercially available GPS receiver unit, with a staff-developed electromechanical shutoff system installed on a portable generator, can distinguish indoor and outdoor environments and shut off the generator accordingly, with the exception of a dense tree cover scenario. If ultimately proven effective and reliable, this technology may not suffice as a sole carbon monoxide (CO) mitigation technology because it does not protect against all generator use scenarios that pose a CO poisoning risk. To protect against CO poisoning resulting from outdoor operation near an opening into a home, as well as to minimize CO accumulation from a generator operating indoors before the GPS receiver/shutdown system can shut it off, additional technology would be needed to reduce the generator's engine CO emission rate. As noted in Reference [1], page 5, deaths have occurred when generators were operating outside the home, near open windows, doors, or vents. CO emission reduction is CPSC staff's primary strategy to reduce the generator CO poisoning hazard; and staff has demonstrated that current emission control technology adapted onto a prototype generator is effective in greatly reducing portable generator CO emissions in generator indoor use scenarios that are commonly fatal. The high CO emission rate of current generator designs can rapidly create an unsafe exposure in the space where the generator is operating, as well as in adjoining spaces. Implementation of a shutoff strategy, without requiring a reduced CO emission rate, can create a hazardous CO exposure if the generator runs for even a brief period of time before indoor operation is detected. Therefore, CPSC staff views a GPS receiver shutoff strategy as a supplemental means of further reducing the risk of CO poisoning [1]. The issue of dense tree cover requires further exploration by GPS technology experts. ESFS staff believes that the challenge posed by the scenarios in this study that involved dense trees can be met as GPS receiver technology continues to evolve and become more sophisticated. However, ESFS staff recommends that the appropriate experts in the GPS/radio frequency (RF) engineering community explore the issue of dense tree cover or any additional situational limitations, …