COUPLING FOR VACUUM-INSULATED PIPING

A coupling is provided for connecting vacuum-insulated piping. The coupling facilitates the detection of unwanted fluid ingress into the low pressure insulating outer portion (18, 20) of the vacuum-insulated piping and the detection of a leak from the inner portion (6, 7) of the vacuum-insulated piping that is used to carry cold fluids. This is achieved by providing a first flow path (12) from the inner portion of the vacuum-insulated piping to a sensor outlet (11) and a second flow path (13) from the outer portion of the vacuum-insulated piping to the sensor outlet (11). One sensor (50) may be used to detect unwanted fluid ingress into the low pressure insulating outer portion and also detect a leak from the inner portion of the vacuum-insulated piping.