Leak Detection Telecom Cables

ANSWER:
This is easy if you use the Duct Probe 8712, which is an accessory to the Hydrogen Leak Detector 9012XRS. You start by injecting the hydrogen tracer gas (5%H2/95%N2) into the pressurized telephone cable. You then insert the Duct Probe 8712 into the duct. The Duct Probe is a 100m long glass fiber rod with the sensor at its tip. The sensor will immediately indicate where the leak is, and you measure how many meters of the rod that has been inserted into the duct. This gives you the position of the leak.
ANSWER:
No, the gas mix of 5% hydrogen in nitrogen can never spontaneously re-concentrate and become explosive. The hydrogen can never reach higher concentrations in the man-hole than the concentration in the gas-bottle. This is according to the 2:nd law of thermo dynamics. There are better reasons to stop smoking.
ANSWER:
Yes, Hydrogen penetrates anything if you wait long enough. Concrete is normally quite porous as is also many other materials we normally think are solid. Practically we have experience in finding leaks where the tracer gas has had to pass through dirt, mud, gravel, snow, concrete, asphalt and various types of tiles and cobble-stone paving
ANSWER:
Yes, hydrogen takes the easiest way up, but will ALSO go straight up from the leak. In real tests you may in a case like this get a strong indication where you know there is no cable, which will tell you that it may just be a puff of hydrogen taking the easiest way up, through a drain, a fissure or something similar. Just go back to where you know the cable is buried and continue your search and I guarantee that you will find your leak.
ANSWER:
No. This is the advantage of our method! Once you have started to inject the trace gas into the telecom cable, the gas will escape through the leak. If you wait long enough there will be so much hydrogen that it will come up around the manhole cover. This can easily be detected by using Surface Probe 8612. You are guided to the right manhole without having to open each and every one. Screening the manholes this way will quickly narrow down the area to search in. Once you have identified the right manhole, you can go down to locate the leak just using the hand probe.