Dual sealing for high pressure gaseous fuels

A fitting assembly for a high-pressure gaseous fluid, the fitting assembly comprising:

• a female connector disposed about an axis and comprising a first sealing surface facing radially outward;
• a male connector configured to be received in the female connector about the axis, the male connector comprising a second sealing surface facing radially inward, the second sealing surface configured to engage the first sealing surface to form a first seal at a first location, wherein at least one of the first sealing surface and the second sealing surface is frustoconical;
• an annular sealing element disposed between the female connector and the male connector to form a second seal at a second location, wherein the annular sealing element comprises oppositely disposed legs configured to engage oppositely disposed third and fourth sealing surfaces of the male connector and the female connector, respectively, and wherein the first location is downstream of the second location on a pathway of potential leakage of the high-pressure gaseous fluid from the second location;
• and
• a threaded coupling nut configured to engage the first and second sealing surfaces and secure the female connector to the male connector.