LNG Tank Certification
The LNG vehicle fuel tanks designed and patented by Cryogenic Fuels are manufactured, tested and certified in compliance with the National Fire Protection Association, NFPA-57, Code For Liquefied Natural Gas Vehicular Fuel Tanks & Fueling Facilities, 2002 Edition.
This code specifies that LNG vehicle fuel tanks "shall be designed, fabricated, tested and marked in accordance with the requirements of DOT Specification 4 L or the "Rules for the Construction of Unfired Pressure Vessels, ASME Boiler and Pressure Vessel Code, applicable at the date of manufacture".
The DOT, Specification 4-L, Section 178.57 provides manufacturers the requirements for the design, fabrication and certification testing of insulated, welded cylinders intended for use in the transportation and handling of non-flammable and flammable cryogenic liquids. Specification 4-L also references other sections of the DOT code on the issues of, sizing of relief systems, fill limits, fill density and markings for 4-L containers. Additional references include Sections 173.316 and 173.18 for "cryogenic liquids in cylinders" & "cargo cryogenic containers".
Crash Test Simulation
In accordance with the certification requirements of the Federal Highway Administration (FHWA) vehicle fuel tanks must be subjected to both a 30’ drop test on one end and a 10’ drop test on the filler neck fitting or plumbing end of the tank. The 30" and 10’drop testing is required on only the largest size tank in a design series. The drop testing and crash simulation testing on the CFI, Model C-100-26-2 LNG fuel tank was successfully performed under DOE Contract No. DE-FCO2-O1CH11084.
Shock & Vibration
In addition to the DOT, NFPA & FHWA certification testing the CFI tank design has also successfully completed dynamic structural testing. The test procedure consisted of 380,000 cycles of 3.5 "G" shock loads, applied to a test tank filled with liquid nitrogen, at design operating pressure. The testing simulated 500,000 miles of heavy-duty truck operational service. The testing was performed by Mack Truck at their test facility in Allentown PA in 1997.
Markings and Reports
The DOT code also requires that the manufacturer shall prepare a report for each tank that contains, at a minimum, the applicable information listed in CGA Pamphlet C-11, in accordance with the test report requirements of this subchapter. Any additional test information or markings that are required by the applicable specification must be shown on the test report. The manufacturer of the cylinders must retain the reports required by this subpart for fifteen (15) years from the original test date of the cylinder. As a matter of practice the purchaser (user) should be provided a copy of the "inspectors report".