Sunday, December 22, 2019

LNG by Rail NPRM Comments – 12-22-19

With one week to go to the original cut off of the comment period on the Liquified Natural Gas (LNG) by Rail notice of proposed rulemaking, the comments that the DOT’s Pipeline and Hazardous Material Safety Administration will have to pay attention to in formulating their final rule have started to come in in larger numbers. I addressed the ones that came in the previous week here. This week’s batch includes comments from:

Association of American Railroads (AAR) and The American Short Line and Regional Railroad Association (ASLRRA);

Lack of Safety Information

A continuing thread seen in comments is the lack of safety information about the proposed shipments of LNG with many commenters quoting the NPRM’s comment that: “It is difficult to estimate the failure rate of the DOT-113 tank car in derailments because railroads are not required to report incidents to PHMSA or FRA unless they meet a baseline threshold.”

Fire Hazards

The NASFM comment notes that there is still a fire hazard from an intact LNG railcar involved in a multicar derailment; stating that: “This is due to several factors, including the time the product would be in the tanks while cleanup is conducted, as they would off-gas from those tanks during cleanup, creating significant hazards.” (pg 2)

The ZFRD comment makes the following comparisons between an LNG release and a liquified propane gas (LPG) release:

• The flammable range for LNG is 35% greater than LPG;
• A gallon of LNG converts to 625 gallons of vapor, for LPG the number is 270 gallons; and
• The LNG ignition temperature is 999˚F, the LPG temperature was not given, but is 410 to 580˚F.

Asphyxiant Hazard

The NASFM comment raises the issue of LNG being an asphyxiant hazard as noted in the NPRM. They note that while the AAR OT-55 quoted in the NPRM makes a training containing a single toxic-inhalation hazard railcar a ‘key train’ that does not apply to asphyxiant hazard containing railcars.


The EJTF comment notes that since the filling density of LNG will be limited by the proposed rule to 32.5%, there will be significant free headspace (they calculate 9.192 gallons) in ‘filled’ railcars which will lead to sloshing of the liquid while the railcars are in motion. They propose that this sloshing in multiple railcars in a consist could contribute to derailments.

DOT 113C120 Railcars

The railroad comment notes that there is a task force (including PHMSA) ‘evaluating the DOT-113 specification for LNG’. Their report should be available next summer. A separate study that has already been completed by AAR recommends the following changes to the current 113C120 tank car standards to improve crash worthiness:

• Increasing the outer tank thickness from 7/16” (the thickness of a standard DOT-113C120 tank car) to 9/16”;
• Increasing the head from 1/2” to 9/16”;
• Increasing the gross rail load to 286,000-pound; and
• Additional hardening of the protective housing for valves and fittings.

The comment from Chart Industries corrects a statement about the LNG railcar in the NPRM. They note that:

“Mylar is a plastic material that is not compatible with the potential flammable gas being in the annular space. The common wrapped insulation used in such tanks is often referred to as Multi-Layer Insulation (MLI), Super Insulation (SI) or Multi Layer Super Insulation.”

Emergency Response Training

The ZFRD comment notes that:

“Fire departments are not well trained or equipped to control, extinguish or mitigate a fire involving one or more LNG tank cars. It is not realistic to think that existing fire department resources, including response of mutual aid fire departments, can intervene and mitigate a fire caused by LNG tank cars in a timely manner.”

The comment above was supported by similar comments from IAFF and IRC.

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