[Federal Register Volume 62, Number 182 (Friday, September 19, 1997)]
[Rules and Regulations]
[Pages 49171-49172]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-24974]


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DEPARTMENT OF TRANSPORTATION

Research and Special Programs Administration

49 CFR Part 171

[Docket No. RSPA-97-2133 (HM-225)]
RIN 2137-AC97


Hazardous Materials: Cargo Tank Motor Vehicles in Liquefied 
Compressed Gas Service; Advisory Guidance for Leak Testing Discharge 
Systems

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

ACTION: Advisory guidance.

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SUMMARY: On August 18, 1997, RSPA published in the Federal Register a 
final rule adopting certain safety standards applicable to cargo tank 
motor vehicles used in liquefied compressed gas

[[Page 49172]]

service. This advisory guidance identifies a potential safety problem 
when leak testing a cargo tank motor vehicle's discharge system and 
clarifies a pressure test requirement for new or repaired transfer 
hoses. It is responsive to a petition for reconsideration and a request 
for clarification.

FOR FURTHER INFORMATION CONTACT: Ronald Kirkpatrick, Office of 
Hazardous Materials Technology, RSPA, Department of Transportation, 400 
Seventh Street, SW., Washington, DC 20590-0001, telephone (202) 366-
4545, or Nancy Machado, Office of the Chief Counsel, RSPA, Department 
of Transportation, 400 Seventh Street, SW., Washington, DC 20590-0001, 
telephone (202) 366-4400.

SUPPLEMENTARY INFORMATION: On August 18, 1997, RSPA published a final 
rule in the Federal Register (62 FR 44038) that adopts temporary 
requirements for cargo tank motor vehicles in certain liquefied 
compressed gas service. It requires a specific marking on affected 
cargo tank motor vehicles and requires motor carriers to comply with 
additional operational controls intended to compensate for the 
inability of passive emergency discharge control systems to function as 
required by the Hazardous Materials Regulations. The interim 
operational controls specified in the rule are intended to assure an 
acceptable level of safety while the industry and government continue 
to work to develop a system that effectively stops the discharge of 
hazardous materials from a cargo tank if there is a failure of a 
transfer hose or piping.
    Following publication of the August 18, 1997 final rule, The 
Fertilizer Institute (TFI) filed a petition for reconsideration 
seeking, in part, a revision to a requirement in Sec. 171.5(a)(1)(i) 
which specifies that an operator must subject the transfer hose to full 
transfer pressure before commencing the first transfer of each day. 
TFI's petition stated, in pertinent part:

    In the final rule, RSPA adopts a requirement concerning the 
pressure testing of the transfer hose prior to the first transfer 
each day. Specifically, RSPA requires that ``prior to commencing the 
first transfer of each day, the transfer hose shall be subjected to 
full transfer pressure.'' 49 CFR 171.5(a)(1)(i). No further guidance 
concerning this requirement is found in the regulations or the 
preamble to the final rule. TFI is concerned that RSPA or Federal 
Highway Administration (FHWA) inspectors may interpret this 
requirement to mandate pressurizing the hose, after opening the 
vapor valves on the cargo tank and customer tank, and engaging the 
power take-off (PTO) without opening the product valve on the 
customer's tank. Under such an interpretation, this requirement is 
unreasonable and not in the public interest. To explain why such a 
requirement is unreasonable and not in the public interest, it is 
necessary to describe a typical anhydrous ammonia unloading 
operation.
    To unload a cargo tank containing ammonia, the operator first 
connects the vapor line from the cargo tank to the customer's tank 
and opens the valve at each end of the line. Next, the operator 
connects the product transfer hose to the cargo tank and customer's 
tank. After making this connection, the operator opens the internal 
valve on the cargo tank to flood the pump and, after the pump is 
flooded, opens the discharge valve on the pump to charge the 
transfer hose. At this point in the delivery process, the transfer 
hose is charged with the product pressure. Next, if there are no 
signs of leakage, then the operator opens the product valve on the 
customer's tank. Finally, the operator engages the PTO to commence 
product transfer.
    If Sec. 171.5(a)(1)(i) is interpreted to require engagement of 
the PTO and pumping against a closed product valve at the customer's 
storage tank, TFI asserts that such a requirement is unreasonable. 
This requirement is unreasonable because pumping against a closed 
valve could cause the vanes in the transfer pump to break. Also, the 
PTO, which is rotating at 650 revolutions per minute, could be 
damaged and break. Because of the likely potential for damage to the 
pump and PTO, it is unreasonable for RSPA to require an ammonia 
cargo tank operator to pump against a closed product valve to ensure 
the integrity of the transfer hose.
    In addition to being unreasonable, such a requirement is not in 
the public interest because failure of the pump or PTO may result in 
injury to the cargo tank operator and public in proximity to the 
unloading operation. If the vanes in the pump break, it is possible 
that the integrity of the pump casing may be compromised, resulting 
in flying debris. Also, a PTO which breaks, while rotating at 650 
revolutions per minute, may cause injury, including death, to those 
within proximity of the cargo tank.
    TFI understands RSPA's concern with ensuring the integrity of 
the transfer hose prior to commencing product transfer. As RSPA is 
aware, TFI has consistently been a proponent through this rulemaking 
of measures designed to ensure the integrity of the transfer hose 
and couplers. TFI believes that RSPA's goal of ensuring that a hose 
is sound prior to commencing transfer may be accomplished through 
the daily visual inspection of the discharge system, including the 
transfer hose and couplers, and charging of the transfer hose with 
product at the pressure within the closed system. This is especially 
true when RSPA considers the safety implications of engaging the PTO 
with the customer's storage tank product valve closed.
    For these reasons, TFI requests that RSPA modify the language in 
49 CFR 171.5(a)(1)(i) to read:
    In addition, prior to commencing the first transfer of each day, 
the transfer hose shall be subjected to product pressure without 
mechanical influence (e.g., engaging the power take-off).

    The provisions of Sec. 171.5(a)(1)(i) are intended to ensure that a 
cargo tank's discharge system, including transfer hose and couplings, 
is subjected to pressure prior to beginning transfer of product from a 
cargo tank motor vehicle to a receiving tank. It is not intended that 
any components of the discharge system should be subjected to pressures 
greater than full transfer pressure as part of this leak test.
    RSPA believes that the problem described by TFI is common to larger 
cargo tank motor vehicles, known as transports, which may not have 
separate back-to-tank bypass valves; smaller cargo tank motor vehicles, 
known as bobtails, generally do have separate back-to-tank bypass 
valves, and during delivery the transfer hose is charged with pump 
discharge pressure all the way to the hose end valve, which tests the 
integrity of the transfer system at each delivery.
    RSPA agrees with TFI's concern that some cargo tank pumping systems 
are not capable of pumping against a closed product valve without being 
damaged. Therefore, operators may determine the leakproofness of a 
delivery system, before beginning transfer of product from a cargo tank 
motor vehicle to a receiving system, by flooding the pump and charging 
the transfer hose with product pressure before the receiving system is 
opened.
    RSPA will publish a response to TFI's petition for rule change and 
petition to extend the termination date of the final rule in the near 
future.
    Section 171.5(a)(1)(ii) requires, in part, that prior to commencing 
transfer using a new or repaired transfer hose or a modified hose 
assembly for the first time, the hose assembly must be subjected to a 
pressure test performed at no less than 120 percent of the design 
pressure or maximum allowable working pressure (MAWP) marked on the 
cargo tank motor vehicle, or the pressure a hose is expected to be 
subjected to during product transfer, whichever is greater. In response 
to a recent telephone inquiry, RSPA noted that this requirement is 
based on the MAWP marked on a cargo tank motor vehicle, not the maximum 
working pressure marked on a transfer hose.

    Issued in Washington, DC on September 16, 1997.
Alan I. Roberts,
Associate Administrator for Hazardous Materials Safety.
[FR Doc. 97-24974 Filed 9-18-97; 8:45 am]
BILLING CODE 4910-60-P