[Federal Register Volume 64, Number 220 (Tuesday, November 16, 1999)]
[Proposed Rules]
[Pages 62161-62162]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-29904]
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DEPARTMENT OF TRANSPORTATION
Research and Special Programs Administration
49 CFR Part 178
[Docket No. RSPA-99-5921(HM-213A)]
RIN 2137-AD34
Hazardous Materials: Cargo Tank Rollover Damage Protection
Requirements
AGENCY: Research and Special Programs Administration (RSPA), DOT.
ACTION: Advance notice of proposed rulemaking (ANPRM).
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SUMMARY: RSPA is requesting comments on a research study conducted by
the University of Michigan Transportation Research Institute (UMTRI)
titled ``The Dynamics of Tank-Vehicle Rollover and the Implications for
Rollover-Protection Devices.'' The intended effect of this action is to
obtain information concerning the need, if any, for amending the
Hazardous Materials Regulations (HMR) concerning cargo tank rollover
damage protection devices, the costs and benefits associated with such
amendments, and ways to minimize impacts on small businesses. This
ANPRM addresses DOT specification cargo tanks used for the
transportation of liquid hazardous materials.
DATES: Comments must be received by May 15, 2000.
ADDRESSES: Submit written comments to the Dockets Management System,
U.S. Department of Transportation, Room PL. 401, 400 Seventh Street,
SW, Washington, DC 20590-0001. Comments should identify the docket
number, RSPA-99-5921 (HM-213A) and submitted in two copies. If you wish
to receive confirmation that RSPA has received your comments, include a
self-addressed stamped postcard. Comments may also be submitted to the
docket electronically by logging onto the Dockets Management System
website at http://dms.dot.gov. Click on ``Help & Information'' to
obtain instructions for filing the document electronically.
The Docket Management System is located on the Plaza Level of the
Nassif Building at the Department of Transportation at the above
address. You may review public dockets between the hours of 10 a.m. and
5 p.m., Monday through Friday, excluding Federal holidays. Internet
users may review all comments received by the U.S. Department of
Transportation by accessing RSPA's Hazmat Safety website at http:/
hazmat.dot.gov.
FOR FURTHER INFORMATION CONTACT: Ms. Jennifer Karim, Office of
Hazardous Materials Standards, Research and Special Programs
Administration, telephone (202) 366-8553; Mr. Ronald Kirkpatrick,
Office of Hazardous Materials Technology, Research and Special Programs
Administration, telephone (202) 366-4545; or Mr. Danny Shelton, Office
of Safety and Technology; Federal Highway Administration, telephone
(202) 366-6121, U.S. Department of Transportation, 400 Seventh Street
SW, Washington, DC.
SUPPLEMENTARY INFORMATION:
I. Background
Between January and May 1991, the National Transportation Safety
Board (NTSB) investigated seven highway accidents involving MC 306, MC
307, and MC 312 specification cargo tank motor vehicles that had
overturned and released hazardous materials. As a result of these
investigations, NTSB published a Hazardous Materials Special
Investigation Report on February 2, 1992. NTSB found that, in all
cases, the rollover protection devices failed to protect the cargo tank
manholes and fittings from damage. NTSB reported that in three of the
accidents structural failure of the rollover protection devices caused
impact damage to the fittings. In the other four accidents, the design
and configuration of the devices were found to be inadequate for
protecting and shielding the top fittings from external objects or from
striking into the ground. The damaged closures or fittings on top of
the cargo tank caused the release of hazardous materials during the
accidents.
In each case, the rollover protection devices failed to protect the
cargo tank manholes and fittings from damage sufficient to result in
loss of lading. The report found that ``* * * there is inadequate
information about the forces that can be encountered in a rollover
accident and the extent to which rollover-protection devices for cargo
tanks can reasonably be designed to withstand these forces * * *'' In
safety recommendation H-92-10, NTSB recommended that RSPA and the
Federal Highway Administration (FHWA) conduct a study to analyze the
forces and energy involved in cargo tank rollover crashes. In response
to NTSB recommendations, FHWA contracted with the University of
Michigan Transportation Research Institute (UMTRI) to conduct a study
on cargo tank rollover protection.
II. UMTRI Study
The results of UMTRI's study are found in a November 1998 report
titled ``The Dynamics of Tank-Vehicle Rollover and the Implications for
Rollover-Protection Devices.'' The study investigated the dynamics of
mild, moderate and severe rollover crash events involving cargo tank
motor vehicles. The crash situations and vehicle characteristics were
influenced by the rollover accidents investigated in the NTSB report.
These were all DOT specification cargo tank motor vehicles and, in each
incident, the top damage protection structures were impacted. In the
UMTRI study, not all simulations resulted in ``rollover'' to this
degree. Vehicle rotations in which the top damage protection is not
affected may be more accurately termed ``overturn.'' UMTRI drew
conclusions from the simulated rollover crashes based on the position
and speed of each modeled tank at the point when it struck the ground.
You may obtain copies of the study by calling the Records Center at
(202) 366-5046, by mailing a request to the Records Center, RSPA, Room
8421, 400 Seventh Street, SW, Washington, DC 20590, or by downloading
the study from the DMS electronic docket at http://dms.dot.gov.
III. Request for Comments
RSPA requests comments responding to the questions listed below to
facilitate decisions on the potential need for additional changes to
the HMR with regard to cargo tank rollover damage protection standards.
Commenters are requested to include information pertaining to their
experience with damages incurred in other rollover accidents. RSPA also
invites comments on any aspect of the UMTRI study not specifically
addressed by questions in this ANPRM. Information, including
photographs, sketches and accident investigation reports, on rollover
accidents in which cargo tank manholes and fittings were, or were not,
damaged would be helpful to RSPA in determining whether to revise the
current requirements. Similarly, information on release of lading
through damaged heads or shell is solicited.
A. Impact Scenarios
Under the heading ``Implications of the Results for Minimum
Performance Requirements for Rollover-Protection
[[Page 62162]]
Devices,'' the UMTRI report lays out three impact scenarios for
rollover crashes based on different levels of severity. To restate and
simplify the rollover events described in B. Rollover Crashes below,
three scenarios affecting impact were formulated: (1) Mild overturn or
rollover, (2) moderate rollover, and (3) more severe rollover. In each
rollover event, it is important to characterize the surface impacted.
For example, type of surface--was it asphalt, concrete highway paving,
wet earth, sand, or rocky shoulder materials; angle of surface--was it
horizontally oriented or did it have an up or down slope; or did the
vehicle strike a vertical object such as a guardrail, curbing or a tree
or pole?
A1. What description of actual accidents can you provide for better
understanding about the nature of the rollover event?
A2. What is your judgement of the severity and application of the
rollover? How can ``severity'' best be characterized?
A3. How did other accidents that you provided information on differ
from the simulations performed in the UMTRI study?
B. Rollover Crashes
The UMTRI study examined the dynamic behavior of cargo tank motor
vehicles by simulating two straight trucks and five tractor semitrailer
combinations in rollover events. The study characterized the simulation
program as follows: ``Each (vehicle) was subjected to 126 simulated
maneuvers intended to result in rollover. Test maneuvers included mild,
low-speed turns that just barely produced rollover, more dynamic
maneuvers on smooth surfaces, and high-speed impacts with curbs and
guardrails that result in rapid rollover with substantial pitch and
yaw.'' In mild overturns, the vehicle may fall onto its side and rotate
no more than 135 degrees, or it may continue to roll on a flat ground
surface to engage the rollover protection devices. In more severe
events, the vehicle may land on its side and slide sideways into any of
the many objects with vertical surfaces that are oriented along the
roadway; such objects include guardrails, retaining walls and
embankments. In somewhat more dynamic rollovers, the vehicle may become
airborne and rotate rapidly enough to bring the rollover protection
devices into direct contact with the ground. For example, this could
happen when the vehicle rolls onto a sloping or depressed roadside
surface or becomes airborne due to striking a curb. On actual rollover
accidents that you are aware of:
B1. What was the approximate rollover rate, impact angle, impact
object, and damage condition of the protection devices?
B2. Were the accident protection devices impacted during the
rollover crash? What was the magnitude of the damage to the tank shell,
fittings, manholes, etc.? What was the damage condition of the
protective devices?
B3. Did the rollover protection devices function as designed? If
not, did they fail because of a design flaw?
C. Rollover Protection Device Performance Goals
The UMTRI report recommends that performance goals for rollover
protection devices should be expressed in terms of impact events rather
than in terms of the strength of the devices. This must include mass,
velocity and surface parameters. The forces acting on the protection
devices are the result of an impact. The protection device should be
designed in such a way as to effectively manage the energy encountered
by the device during a rollover impact.
UMTRI suggests that the design of rollover protection devices
should be able to provide protection when an impact onto a flat surface
normal to the surface of the cargo tank occurs at velocities of at
least 12 ft/sec, and further that this occurs at angular orientations
of the tank with respect to the impact surface which are representative
of actual incidents. They suggest that impact velocities of up to 24
ft/sec would be desirable.
C1. What approach should be used in defining the performance goals
for rollover protection devices? Should a performance goal be based on
impact energy absorption and distribution? Should performance testing
be used to validate calculations?
C2. What minimum design goals should be required for rollover
damage protection devices? Should design goals establish a finite space
into which the protection device could be displaced without contacting
the protected fittings? Conceptually, should this be done along the
lines of rear-end protection devices as set forth in Sec. 178.345-
8(d)(1)?
C3. Should the design goals be based on impact velocity as
suggested by UMTRI?
C4. If impact velocity is used, what is an advisable value that
will cover the majority of accidents?
D. Feasibility of UMTRI Recommendations
If implemented, the UMTRI recommendations for designing rollover
protection devices would require more sophisticated analyses on the
part of cargo tank designers and manufacturers to assure that rollover
protection devices meet specified performance goals.
D1. What degree of economic burden, if any, would performance goals
impose on small businesses such as manufacturers and engineering
consultants? Would requirements for computerized analysis impose an
economic burden on small businesses which may be more apt to rely on
hand calculations?
D2. Would a standard design, validated to satisfy a given
performance standard, be an acceptable alternative to a performance
standard? Would this approach minimize economic impact on small
business?
D3. What additional economic burdens might cargo tank designers and
manufacturers incur if the UMTRI recommendations are adopted?
E. Application to Existing Cargo Tank Motor Vehicles
If we adopt new rollover protection device design requirements, we
will need to decide whether and to what extent to apply the new
requirements to cargo tank motor vehicles that are already in service.
E1. Should any new performance criteria for rollover damage
protection devices be applied to cargo tank motor vehicles currently in
hazardous materials transportation service?
E2. Should there be a provision proposing new standards for
rollover damage protection devices which limits the amount of time a
cargo tank motor vehicle currently in service may be used if it does
not meet the new requirements?
E3. Should a retrofit or phase out provision be applicable to all
cargo tank motor vehicles currently in service or just to cargo tanks
manufactured under superseded specifications, such as MC 306, MC 307
and MC 312?
E4. What economic burden would cargo tank owners incur if they are
required to retrofit or replace cargo tank motor vehicles that do not
meet the new performance criteria?
Issued in Washington, DC on November 10, 1999, under authority
delegated in 49 CFR part 106.
Alan I. Roberts,
Associate Administrator for Hazardous Materials Safety, Research and
Special Programs Administration.
[FR Doc. 99-29904 Filed 11-15-99; 8:45 am]
BILLING CODE 4910-60-P