Zythryn wrote:GRA wrote:Just found this, although it dates from Feb. 11th:https://www.ntsb.gov/investigations/AccidentReports/Reports/HMD18FR001-preliminary.pdfPRELIMINARY REPORT
High-Pressure Hydrogen Gas Cylinder
Fire During Transportation
Diamond Bar, California
February 11, 2018
HMD18FR001. . . Preliminary findings from the investigation include the following:
• The 25 aluminum-lined carbon composite gas cylinders were each 120 inches in length,
17.8 inches in diameter, and had a nominal water capacity of 18,716 cubic inches
• The cylinder module was shipped with all but one cylinder full. Each cylinder contained
about 10.0 kg of hydrogen at a pressure of approximately 7,500 PSI gauge (psig).
• Cylinder damage was limited to fire exposure.Twenty of the cylinders exhibited varying
degrees of fire exposure, but none of them were breached[/b] (see Figure 2).
• Pressure relief devices activated on 12 of the cylinders.
• The cylinder manufacturer specifications call for type CG-5 pressure relief devices set at
10,000 psig.1 However, NTSB investigators and investigation party members found
pressure relief devices set at an incorrect pressure rating of 5,833 psig installed in three
of the cylinders. Two of these under-rated pressure relief devices had activated. The
source of the incorrect pressure relief devices is under investigation.
• The trailer included tubing attached to each pressure relief device outlet to safely vent
relieved gases upward to the outside top of the cylinder module. Seven of the vent tubes
became detached from the pressure relief device assemblies and vented gas to the interior
of the trailer, which fueled the fire. The separated tubing had not been tightly secured by
the compression fittings.
• The incorrectly rated pressure relief devices and unsecured vent tubing were not identified
during the cylinder requalification inspections at FIBA Technologies Inc.
• Responding to initial findings, Air Products inspected its remaining fleet of 13 hydrogen
cylinder modules. One trailer undergoing qualification inspection was found to have a
cylinder with an underrated pressure relief device. Improperly secured vent tubing was
found in about half of all the lines inspected.
• Air Products and FIBA have revised the requalification inspection procedures to address
fittings securement and pressure relief device compatibility.
Interesting how the same piece can read very different simply by changing the bolder text.
Indeed. And your point being?