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On May 31, 2001, about 3:28 p.m. central daylight time, a southbound Gayle Stuart Trucking, Inc., truck-tractor semitrailer exited Interstate 540 at State Highway 282 (SH-282) near Mountainburg, Arkansas. The driver was unable to stop at the stop sign at the bottom of the ramp. The 79,040-pound combination unit was traveling approximately 48 mph when it entered the intersection and collided with the right side of a westbound, 65-passenger, 1990 Blue Bird Corporation school bus operated by the Mountainburg, Arkansas, Public Schools. The school bus rotated approximately 300 degrees clockwise and overturned; the body, which partially separated from the chassis, came to rest on its right side on the eastbound shoulder of SH-282. The tractor semitrailer continued across the roadway, rotated about 60 degrees clockwise, overturned, and came to rest on its left side. Three school bus passengers seated across from the impact area were fatally injured; one was partially ejected. Two other passengers, one of whom was seated in the impact area, received serious injuries, and four passengers had minor injuries. The school bus driver and the truckdriver both sustained minor injuries.
The National Transportation Safety Board recommends that the National Highway Traffic Safety Administration: Obtain the authority, as necessary, and include propane fuel system integrity standards for aftermarket installations in the Federal Motor Vehicle Safety Standards.
Original recommendation transmittal letter:
Closed - Acceptable Alternate Action
Mountainburg, AR, United States
Collision Between Truck-Tractor Semitrailer and School Bus
Addressee(s) and Addressee Status:
NHTSA (Closed - Acceptable Alternate Action)
Safety Recommendation History
On August 20, 2003, staff from the Safety Board and NHTSA discussed alternate means of meeting the intent of Safety Recommendation H-02-19. NHTSA now suggests that a more effective response to the Board's recommendation would be to work with the National Fire Protection Association (NFPA) to update Standard No. 58, Liquefied Petroleum Gas Code, to require protection for after-market propane fuel systems. Such a change would have the effect of a regulation, as all States except Idaho require that conversions be installed in accordance with Standard No. 58. In a December 2003 response to a corresponding recommendation (H-02-21) issued to the NFPA, that agency provided detailed information concerning changes to the 2004 edition of Standard No. 58. The current requirements of NFPA 58, and revisions already in progress for the 2004 edition, provide protection for propane fuel containers used on vehicles (including school buses). The committee revised section 8.2.3 (g) (Proposal 58-103) to enhance the integrity of all propane engine fuel systems. This change requires installation of a valve in the liquid outlet connection of a propane engine fuel container, which is actuated both manually and automatically when the engine is not in operating mode, independent of the ignition switch position. The NFPA noted that this new valve requirement is in addition to the requirement for an excess flow valve in the liquid outlet of the vehicular propane container. In implementing this additional requirement, the committee recognized that excess flow valves could not be relied upon to stop flow in all accident conditions. In the same response, the NFPA included information from the Technology and Standards Committee of the National Propane Gas Association (NPGA) concerning crash tests of propane-fueled vehicles. Both associations believe that the tests confirm that an adequate level of protection exists in the case of an accident. The NPGA noted that a propane engine fuel container is an American Society of Mechanical Engineers (ASME) pressure vessel that provides a significantly greater level of protection than the tanks used for liquid fuels on vehicles (including school buses). The NPGA further noted that ASME containers used in propane service are required to have a design pressure of 250 pounds/square inch (psi), and that ASME containers used in propane service as vehicular fuel containers are required to have a design pressure of 312 psi, a 25-percent increase in working pressure, with a corresponding increase in shell thickness. The ASME code requires a design margin of 3.5, providing additional container thickness. In addition, the cylindrical shape of an ASME propane engine fuel container provides additional ability to withstand damage. The NPGA noted that liquid fuel containers are thin-walled vessels designed to contain the liquid only. Where installed on vehicles, they require protection not needed for propane containers. In contrast, as noted above, propane containers used on school buses for engine fuel applications have significant crashworthiness due to their design characteristics. The NPGA also provided examples of bus crash and tank drop tests that demonstrated this increased crashworthiness of the vehicle propane fuel tanks. The Safety Board is persuaded by the NFPA's documentation of the NPGA's fuel container testing and agrees that increased crash protection does not appear warranted. We also believe that the addition of outlet valving controlled by the engine operating mode, coupled with the installation of an excess flow valve, satisfies this recommendation in an acceptable alternate manner, as it enhances the integrity and safety of vehicle propane fuels systems on school buses. Accordingly, Safety Recommendation H-02-19 is classified "Closed--Acceptable Alternate Action."
Letter Mail Controlled 10/2/2003 7:13:03 AM MC# 2030501 As noted in your May 5,2003 letter, NHTSA's authority to issue FMVSSs is limited to newly manufactured motor vehicles and motor vehicle equipment. NHTSA is not aware of any incidents where aftermarket LPG fuel systems on school buses have been a contributing factor to injuries or fatalities in school bus crashes. Therefore, NHTSA does not have sufficient justification to seek authority to regulate aftermarket fuel system conversions on school buses. As yea are aware, State governments' have the responsibility to implement regulations on aftermarket installations such as LPG fuel conversions on school buses. NHTSA shares NTSB's concern that LPG fuel systems are sometimes installed on school buses without any protection or provisions to ensure the integrity of the school buses' LPG fuel system in a crash. Therefore, NHTSA suggests the following alternative approach, because we believe it would likely have greater impact on safety. Currently most, if not all, States require that school buses be inspected annually. The States also have the authority and the ability to ensure that, during these inspections, aftermarket LPG fuel system conversions are performed in accordance with State laws and/or industry standards such as the National Fire Protection Association (NFPA) Standard No. 58, "Standard for the Storage and Handling of Liquefied Petroleum Gases." As noted in your letter, all States except Idaho require that these conversions be installed in accordance with NFPA Standard No. 58. However, as your letter also noted, NFPA Standard No. 58 does not have provisions for LPG fuel systems installed on school buses. NHTSA believes that improvements in safety can be better met by working with NFPA to bring about changes to Standard No. 58 so that LPG fuel systems installed in aftermarket school bus conversions have fuel system protection in the event of a crash. WC suggest that NHTSA work with NFPA to include provisions requiring LPG fuel systems installed on school buses to have shielding that will protect the fuel system during a crash. NHTSA is aware that NTSB issued a safety recommendation (H-02-21) to NFPA to change Standard No. 58 to require that propane fuel systems installed in school buses be protected and that the propane fuel systems meet the equivalent to FMVSS No. 301 "Fuel system integrity," and we are willing to work with the NFPA to ensure that this is done properly. Therefore, NHTSA requests that NTSB reconsider the "Open Unacceptable Response" to Safety Recommendation H-02-19, and change it to "Open Acceptable Alternative Action."
When issuing this recommendation, the Safety Board was aware that NHTSA's authority to issue FMVSS is limited by law to newly manufactured motor vehicles and motor vehicle equipment. In addition, the Safety Board was aware that all States, with the exception of Idaho, implement regulations on aftermarket installations such as propane or liquefied petroleum gas (LPG) fuel conversions on school buses and that they require that propane systems meet National Fire Protection Association (NFPA) standards. However, not even NFPA standards adequately protect children on buses with LPG fuel systems. Under NFPA standards, a rigid safety cage such as the one that protects gasoline and diesel fuel tanks is not required around propane tanks. The Board has investigated school bus crashes in which cages did not enclose LPG fuel tanks, and severe fires and loss of life ensued. The best way to ensure safety of children on school buses that have propane fuel systems added after buses are purchased is to implement Safety Recommendation H-02-19 as it is written. The Safety Board specifically requests that NHTSA seek the authority to regulate after-market installation of LPG fuel systems on school buses. Until this occurs, children riding on school buses that have aftermarket LPG fuel systems will not receive the same level of protection as those children riding on buses equipped with gasoline, diesel or compressed natural gas tanks, all of which NHTSA regulates. Your response suggests that, as an alternative to Safety Recommendation H-02-19, NHTSA explore the feasibility of establishing a FMVSS requirement for LPG fuel systems on newly manufactured buses. While this is a useful proposal, no new buses are equipped with propane fuel systems; all propane fuel systems are currently installed on school buses solely as aftermarket systems. Therefore, the Safety Board believes that establishing a FMVSS requirement for propane fuel systems on newly manufactured buses would be ineffective. The Safety Board believes in demanding the same high level of safety for all children riding on school buses in all 50 States. NHTSA has the authority to ensure that this high level of safety is achieved. Pending actions to include integrity standards in the FMVSS for propane fuel systems installed after bus purchase, Safety Recommendation H-02-19 is classified "Open--Unacceptable Response."
Letter Mail Controlled 01/02/2003 12:07:46 PM MC# 2030002 NHTSA notes that it is currently the State government's responsibility to implement regulations on aftermarket installations such as LPG fuel conversions on school buses. As noted by NTSB, all States, with the exception of Idaho, require that these conversions be installed in accordance with the National Fire Protection Association (NFPA) Standard No. 58, "Standard for the Storage and Handling of Liquefied Petroleum Gases." However, as also noted by NTSB, NFPA Standard No. 58 does not have any provision that LPG fuel systems installed on school buses have shielding to protect the fuel system during a crash. NHTSA is aware that NTSB issued a similar Safety Recommendation (H-02-21) to NFPA to change its Standard No. 58 to require that propane fuel systems installed in school buses be protected, and that the propane fuel systems meet the equivalent to Federal Motor Vehicle Safety Standard (FMVSS) No. 301, "Fuel system integrity." As noted by NTSB, NHTSA's authority to issue FMVSSs is limited by law to newly manufactured motor vehicles and motor vehicle equipment. An effort to get congress to change the law takes significant time and resources, with no assurance of success. We do not believe this is the best course to follow to address this issue. NHTSA shares NTSB's concern that LPG fuel systems are sometimes installed on school buses without any protection or provisions to ensure the integrity of the fuel system in a crash. Therefore, we propose that as an alternative, Safety Recommendation H-02-19 be modified to require that NHTSA explore the feasibility of establishing a FMVSS requirement for LPG fuel systems on newly manufactured school buses. NHTSA believes this approach would have a greater likelihood of achieving the intended result relatively quickly. While exploring the feasibility of establishing a FMVSS requirement, NHTSA would work with NFPA to bring about changes to Standard No. 58 so that LPG fuel systems installed in aftermarket school bus conversions would have a similar requirement. Currently most, if not all, States require that school buses be inspected annually. The States also have the authority and the ability to ensure that, during these inspections, aftermarket LPG fuel system conversions are performed in accordance with State laws and/or industry standards such as NFPA Standard No. 58. I would like to request that this response be listed as "Open, Acceptable Response."
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