96-31731. Advisory Guidance; Transportation of Hazardous Materials in MC 330 and MC 331 Cargo Tanks

[Federal Register Volume 61, Number 241 (Friday, December 13, 1996)]
[Rules and Regulations]
[Pages 65480-65481]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-31731]


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DEPARTMENT OF TRANSPORTATION
49 CFR Chapter I

[Notice No. 96-24]


Advisory Guidance; Transportation of Hazardous Materials in MC 
330 and MC 331 Cargo Tanks

AGENCY: Research and Special Programs Administration (RSPA), DOT.

ACTION: Advisory guidance.

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SUMMARY: Recently, RSPA was advised by the Federal Highway 
Administration of a hazardous materials incident which occurred in 
North Carolina on September 8, 1996. Preliminary information suggests 
there may be a problem in the unloading configuration of a number of MC 
330 and MC 331 cargo tank motor vehicles used to

[[Page 65481]]

transport liquefied petroleum gas. The problem may result in a failure 
of a cargo tank's excess flow feature within its emergency discharge 
control system to function when a transfer hose or piping fails. 
Persons involved in the design, manufacture, assembly, maintenance, or 
transportation of hazardous materials in MC 330 and MC 331 cargo tank 
motor vehicles are reminded that these tanks and their components must 
conform to the Hazardous Materials Regulations.

FOR FURTHER INFORMATION CONTACT: Ron Kirkpatrick, Office of Hazardous 
Materials Technology, Research and Special Programs Administration, 
telephone [phone], or Steve Keppler, Office of Motor Carrier 
Safety and Technology, Safety & Hazardous Materials Division, Federal 
Highway Administration, telephone [phone], U.S. Department of 
Transporta- tion, 400 Seventh Street, S.W., Washington, D.C. 20590-
0001.

SUPPLEMENTARY INFORMATION: On September 8, 1996, more than 35,000 
gallons of propane were released during a delivery at a bulk storage 
facility in Sanford, NC. During the unloading of an MC 331 cargo tank 
into two 30,000-gallon storage tanks, the discharge hose became 
separated from its hose coupling at the storage tank inlet connection. 
Most of the cargo tank's 9800 gallons and more than 30,000 gallons from 
the storage tanks were released during this incident.
    The driver became aware of the system failure when the hose began 
to violently oscillate while releasing liquid propane. He immediately 
shut down the engine, stopping the discharge pump, but he could not 
access the remote closure control to close the internal stop valve. The 
excess flow feature of the emergency discharge control system did not 
function, and propane continued to be released from the system. 
Additionally, the back flow check valve on the storage tank system did 
not function and propane was released from the storage tanks. In light 
of the large quantity of propane released, this incident could have 
resulted in a loss of life and significant property damage if the gas 
had reached an ignition source. Fortunately, there was no fire.
    Over the past ten years, nine similar instances of propane release 
have been reported that involved local deliveries by small cargo tank 
motor vehicles. In each instance, the amount of propane released was 
much less than in the Sanford incident. However, fires resulted in the 
majority of these incidents, and several persons were injured. From a 
review of the reports, it appears that the excess flow feature of the 
emergency discharge control systems did not function as intended. In 
most cases, leakage was stopped by using the remote emergency shut-down 
operator to close the internal stop valve.
    Manufacturers of MC 331 cargo tanks and persons who operate, 
repair, test, inspect, assemble or modify MC 330 or MC 331 cargo tanks 
are reminded of the following requirement in the Hazardous Materials 
Regulations (HMR):
    For MC 331 cargo tanks intended for use in transporting compressed 
gas (except carbon dioxide, refrigerated liquid), Sec. 178.337-
11(a)(1)(i) specifies: Each internal self-closing stop valve and excess 
flow valve must automatically close if any of its attachments are 
sheared off or if any attached hoses or piping are separated.
    Although the regulatory citation is not the same as when the rule 
was first adopted, this requirement has been in the HMR for more than 
forty years.
    For MC 330 and MC 331 cargo tanks, Sec. 173.315(n) specifies: Each 
MC 330 and MC 331 cargo tank used to transport a flammable gas, 
anhydrous ammonia or hydrogen chloride, refrigerated liquid must have 
each liquid opening equipped in accordance with Sec. 178.337-11 of this 
subchapter.
    Similar requirements also are specified in Occupational Safety and 
Health Administration regulations (29 CFR 1910.110) and in the National 
Fire Protection Association's ``Standard for the Storage and Handling 
of Liquefied Petroleum Gases'' (NFPA 58).
    On June 14, 1996, RSPA published a document entitled ``Advisory 
Guidance; Offering, Accepting, and Transporting Hazardous Materials'' 
in the Federal Register (61 FR 30444). The guidance addressed a number 
of topics related to the safe transportation of hazardous materials. 
Persons who supervise or perform hazardous materials functions, 
including persons who design, manufacture, assemble, maintain or 
operate cargo tanks, or otherwise perform functions leading to the 
introduction of hazardous materials into transportation, are encouraged 
to review the guidance in its entirety and to take all necessary 
measures to ensure compliance with the HMR.

    Issued in Washington, DC on December 10, 1996.
Alan I. Roberts,
Associate Administrator for Hazardous Materials Safety.
[FR Doc. 96-31731 Filed 12-12-96; 8:45 am]
BILLING CODE 4910-60-P