Melting Manway Covers on Tank Cars Trigger Safety Advisory
The Pipeline and Hazardous Materials Safety Administration (PHMSA) is alerting hazmat rail tank car owners and offerors of the potential for the aluminum manway covers to melt when exposed to extreme heat. The agency urges all hazmat tank car owners and offerors to inspect their fleets for any rail tank cars currently equipped with aluminum protective housing and consider replacing them with carbon steel housing.
While the March 2 safety advisory is currently a recommendation and not mandatory, PHMSA and the Federal Railway Administration (FRA) may take additional action in the future if investigations reveal that the destruction of the aluminum manway covers and presence of melted aluminum inside the protective housing significantly contribute to improper functioning of pressure relief devices.
Derailment exposes weakness
On February 3, 2023, a train transporting 149 railcars derailed in East Palestine, Ohio. Thirty-eight railcars derailed, including 11 tank cars carrying combustible liquid and flammable gas. The derailment caused a fire impacting the derailed tank cars and damaging 12 additional railcars.
During the initial investigation of the derailment, the National Transportation Safety Board (NTSB) advised PHMSA that three tank cars containing vinyl chloride were equipped with aluminum manway protective housing covers. The primary function of a manway protective housing and cover is to protect tank car fittings, such as pressure relief valves and other fittings, from damage.
The NTSB’s investigation indicated that the aluminum covers melted during the fire, and melted aluminum was observed around the valves inside the protective housing. The investigation has yet to determine what impact, if any, the destruction of the manway protective housing covers had on the performance of the pressure relief devices of the tank cars.
Meeting industry standards
As a result of the NTSB’s findings, PHMSA, in consultation with FRA, issued the safety advisory to inform and caution hazmat tank car owners and offerors regarding the survivability of the aluminum protective housing covers. Although it is currently unclear what impact the protective housing covers may have had on the severity of the damage resulting from the derailment, PHMSA is concerned that the melting of these covers may present a danger in pool fire situations.
All tank car owners and offerors should review their fleets to determine whether their tank cars are equipped with aluminum manway covers. If equipped with the aluminum manway covers, they should replace them with carbon steel equipment, which is the current industry standard.
Key to remember: PHMSA recommends that rail tank owners inspect their fleet and replace aluminum manway covers with carbon steel manway covers. This request is currently not mandatory. However, PHMSA could make it mandatory in the future.