UN WP.15 (Carriage of Dangerous Goods) and ADR regulatory issues regarding CNG and LNG safety on ADR-regulated trucks

42. Mr. Seisler presented the problems associated with language in the ADR that says if the fuel leaks from the tank (on the vehicle) [it] should go to the ground, which is not necessarily the case with gaseous fuels (although LNG and LPG initially are heavier than air until they vaporize). He presents the results to date of the LNG TF discussions and the proposed language for an amendment.

Comments on the presentation:
43. If the text includes the phrase ‘above the auto ignition temperature of the fuel’ LNG dilution should be mentioned.

44. The language might include the flammability range of diesel and LNG, particularly if it is raised in the amendment.

45. Focusing on the word ‘leakage’ only without looking at the practical results that might not result in a fire.

46. Where are the ‘hot parts’ of the truck? Turbo charger; exhaust pipe; other engine components. But the chance of leakage near hot parts of the engine and the dispersion of LNG at that point suggests that the LNG is likely out of the flammability range. But there also could be a spark from an electrical component (i.e. in a garage).

47. A more scientific approach could/might be taken to study where the fuel goes and if it can come into contact with hot parts of the engine or hot parts of the load.

48. Mr. Piccolo knows someone who has some ADR expertise who might be able to assist with the amendment.

Preventing LNG fuel downstream of the vaporizer

49. Mr. Dekker: There are temperature sensors that can be used to detect temperatures lower than design temperatures of the components downstream of the vaporizer. This was raised by Andrew Whitehouse (CAP) during the last LNG Task Force teleconference also as one of the possible safety ‘systems’ that could be provided under the proposed amendment.

50. Mr. Piccolo noted that there is a concern temperatures downstream on non-LNG components. Mr. Whelan indicated that there are safety features to identify low temperatures that might affect, for example, a CNG solenoid valve. Also, too much cold fuel will shut down the engine.

Minimum height of LNG tank mounted on the truck

51. Mr. Dekker said that 200 mm should be the minimum height above the ground, taking into consideration things like traffic calming measures (also called ‘speed bumps’/’sleeping policemen’). What happens if the truck wheels are on either side of the speed bump and it comes in contact with a low-hung fuel tank?

52. Mr. Rijnders asked if the original Scania tank language said ‘shall’ or ‘or (in front of the container and/or tank shall not touch the ground if any tire or tires are deflated)’. The Dutch had prescribed 200mm and if it is lower there should be protection on the tank. Mr. Seisler indicated that the LNG TF had such a discussion and the solutions were too cumbersome.

53. Mr. Dekker asked if the 200mm shall be ‘from the lowest part of the tank.’ Mr. Seisler indicated that this comment would be raised in the next discussion of the LNG TF, scheduled for 16th December 2013.