Trace Surveys trace pipes in four main ways:
Thermography Thermal Imaging allows us to see the effect of a hot or cold water pipe influencing the temperature of the building finishes around it. Where a leak is present we can often see a spreading area around the line of the pipe where the hot or cold water is heating or cooling a wider area than intact section of pipe.
Acoustic Leak Detection We use very sensitive microphones to listen to and measure the noise level over a pipe. Escaping water or gas from a pipe will make noise so the position of the leak is determined by assessing the leak noise level over the pipes length.
Leak Noise Correlators Correlators work by calculating the distance to a leak from two or more fixed points on a pipe. The calculation is based on the time delay between a leak noise being audible at one sensor and the duration of time it takes before the same noise is audible at the next.
Trace Gas Leak Detection Trace Gas is injected into the pipe and forced out through the leak. The gas consists of very small light molecules that tend to travel up and through the materials above the leak. The surveyor scans the rout of the pipe with a trace gas sensor and finds the points where trace gas is surfacing around the leak. The leaks location should always be confirmed using an alternative leak detection method in case something has caused the trace gas to migrate from the leak site.
Moisture Mapping Damp meters and moisture measuring devices are used to find areas of saturation inside an element to help determine where the water is originating from.
Ultrasonic Leak Detection Compressed air escaping through a leak emits some ultrasonic frequencies. By pressurising the leaking pipe with compressed air we are able to scan the route of the pipe with an ultrasound detector and locate leak by identifying where the higher ultrasound levels are found.
Pipe tracing Trace surveys trace pipes in three main ways. Thermal Imaging – The route of the pipe can often be seen with a thermal imaging camera when the fluid running through the pipe is able to influence the surface temperature of the ground above the pipe. Electronic Pipe Tracing – An electric pulse is introduced through the pipe wall or through a cable inserted through the pipe. The current gives off a magnetic field and we trace that field at ground level. Acoustic Pipe Tracing – We have devices that introduce noise through the water inside the pipe. The noise can then be traced at surface level using a listening devise.
Tottenham FC’s Enfield Ground Hydrogen leak detection survey on undersoil heating pipework