by Jack Rosebro
|A Chicago Fire Department firefighter using a hydraulic cutter to remove the roof off of a pre-production Chevrolet Volt during a demonstration at the 2010 Fire-Rescue Conference International in Chicago. Click to enlarge.|
Using a pre-production example of the Chevrolet Volt as a teaching tool, General Motors launched a nationwide electric vehicle training tour and outreach project for emergency personnel this week at the 2010 Fire-Rescue International Conference in Chicago. The workshop included classroom training as well as a live extrication exercise in which Chicago firefighters practiced door and roof removal before an audience of several hundred firefighters.
Material presented in the workshop is the product of several months of collaboration with representatives of organizations such as the International Association of Fire Chiefs (IAFC), International Association of Fire Fighters (IAFF), Illinois Professional Firefighters’ Association (IFPA), National Emergency Number Association (NENA), and the National Fire Protection Association (NFPA).
|A Chicago Fire Department firefighter using a hydraulic spreader to perform a “dash roll” of a pre-production Chevrolet Volt, as part of a demonstration at the 2010 Fire-Rescue Conference International in Chicago. Click to enlarge.|
Three pilot workshops were also held in which the automaker incorporated feedback from extrication specialists and first responders into GM’s electric vehicle curriculum for emergency personnel.
Additional workshops are planned for cities including Detroit, Los Angeles, San Francisco, and Washington, D.C., in support of the rollout of the Volt in select markets later this year. General Motors will also issue an emergency response guide (ERG) for the Volt, and will make the guide available at its Service Technical College website’s first responder page.
Powering Down The Electric Powertrain. The live extrication exercise was performed on one of more than a hundred pre-production Volts that had been subjected to crash testing. Chicago firefighters demonstrated the sequence of tasks required to safely disable the vehicle’s powertrain and extricate injured occupants.
|Underhood warning label for emergency personnel, showing cut point location to disable the Chevrolet Volt’s 12V electrical system, which controls the vehicle's high voltage circuits. Click to enlarge.|
After inspecting the instrument panel to verify that a crashed Chevrolet Volt has been turned off, emergency personnel are advised to stabilize the vehicle with a standard “chock and block” procedure, and then deflate the vehicle’s tires to ensure that the vehicle remains stable during cutting and extrication operations. The vehicle’s 12 volt electrical system, which controls its high-voltage components, is then disabled by cutting its 12V battery cables at designated cut points behind a trim panel at the rear of the car.
Although a removable high-voltage service plug in the Volt’s rear center console can be used to disable high voltage components, it is designed primarily for use by automotive technicians, and can be difficult to access at the scene of an accident.
On-Board Safety Systems. As with many current passenger vehicles, the Volt automatically unlocks its doors, activates its emergency flashers, and disables its fuel pump when an airbag signal is generated. The Volt also employs two front occupant airbags, two front knee airbags, two full side curtain airbags, and two rear airbags. Airbag inflator locations are marked so that firefighters will avoid attempting cuts at or near those areas.
|An LG Chem lithium-ion battery cell, as used in the 2011 Chevrolet Volt. Click to enlarge.|
The 360V, liquid-cooled lithium-ion battery pack, which one GM representative referred to as the “fifth passenger”, is bolted to the underside of the vehicle floor from underneath. The battery pack has been subjected to a wide range of abuse tests, including overcharge, discharge, vibration, excess heat and cold, short circuit, humidity, fire, crush, water immersion, salt water immersion, and nail penetration.
GM recommends that a Volt battery fire be fought with water rather that dry chemicals, and rates the Volt battery as having no explosion or electrocution hazard as the result of a collision. The high-voltage system is designed to shut down automatically in the event of an airbag deployment, and to detect a loss of communication from an airbag control module.
|The Chevrolet Volt’s structural steel, with high-strength steel highlighted in blue. According to GM, the Volt’s 70% high-strength structural steel content is the highest percentage in the industry. Click to enlarge.|
Ultra High Strength Steels Present Challenges. The live exercise in Chicago also highlighted a potential issue for first responders with the Volt as well as with many other late-model vehicles: the inability of some emergency cutting tools to penetrate ultra high strength steel such as boron or martensite.
High-strength structural steel was first employed in some Volvo vehicles in the late 1990s, and is now becoming more commonplace in the industry, particularly in light of new National Highway and Traffic Safety Administration (NHTSA) federal motor vehicle safety standards (FMVSS) concerning side impact protection and roof strength integrity.
More than 70% of the Volt’s structural steel is ultra high strength steel, including the floor, which supports the vehicle’s battery pack.
Reciprocating saws are largely ineffective on high-strength steel, and high-speed rotary cutoff saws present a sparking and fire hazard. Furthermore, the jaws of older hydraulic cutting tools may spread from excessive side loads when a cut is attempted on the newer materials. Most extrication equipment providers now offer hydraulic tools that have been upgraded to work with the new steels.
Refining OnStar Services For The Volt. Representatives from General Motors subsidiary OnStar confirmed that the Volt’s powertrain configuration will automatically be transmitted to its advisors in the event of a crash that triggers OnStar services. Dispatched first responders can then be notified that the Volt has an electric powertrain before they arrive at the scene of the accident.
OnStar application advisors can triangulate the vehicle’s position to determine if it has left the roadway, and can sound the vehicle’s horn to help emergency personnel locate the vehicle.
OnStar also announced the development of an Impact Severity Predictor (ISP), a computer program that evaluates parameters such as air bag deployment, intensity and angle of impact, the presence of multiple impacts and/or rollover events. The ISP then uses an algorithm to predict the likelihood and expected severity of injuries within the vehicle. GM is working with the Center for Disease Control (CDC) to develop a unified injury severity score which can be transmitted to 911 operators through GM’s OnStar emergency services network.
As about half of the nation’s 911 services give no medical instructions to injured callers, OnStar is also training their Level 2 application advisors to provide emergency medical dispatch (EMD) services, using internationally accepted MPDS (medical priority dispatch system) protocols to assist injured callers while emergency services are en route.
OnStar employs approximately 2000 application advisors, and responds to roughly 10,000 requests for emergency services each month, including around 2,000 crash events.
GM hosted Green Car Congress at the event.