Detectable Rodder Locating
Inspection of the Belmont car park soak wells
Brief Summary
Explaining the many uses and easy setup of using a detectable duct rodder (flexitrace)
What is a detectable rodder with an inbuilt sonde?
A detectable rodder is a combination of high-quality fibre glass filaments and resins bonded together with two copper tracer wires along the length of the coil to produce a highly flexible, strong and durable rod.
The rodder comes in many different thicknesses e.g. 4.5mm to 12mm and length e.g. 30m to 300m the choice of size is usually governed by job application (for example using a small dia rodder in a large bore pipe over a long distance will cause the rodder to snake which will build up fiction and prevent the rodder from moving further down the pipe) A sonde is a signal generator attached to the end of the rodder and energized by a locating transmitter.
Equipment
Cable locating transmitter, receiver with direct connection lead and detectable rodder
Application
A direct connect transmitter will energize the rodder to produce an active signal along the length of the rodder or to only energize the sonde. Once the line has been energized with a signal being radiated from the rodder or sonde the locating receiver will detect the signal and enable locating. The below left image shows a direct connection to only one terminal which will energize the length of the rodder, while the right images show a connection to bother terminals which will energize the sonde only. (Note the transmitter frequency needs to match the sonde’s manufactured frequency)
Subject site
Finding and mapping the connecting PVC drainage pipes to soak wells around a Belmont office car park in Perth, Western Australia.
Procedure
Inspection of the Belmont car park soak wells identified connecting PVC piping that required locating to allow for excavation works. As PVC cannot be signal induced a rodder (flexitrace) was inserted along the length of the pipe and energized on one terminal to allow for depth and directional marking, connecting the transmitter to both terminals would energize the sonde and a signal frequency would be produced for spot locating of the sonde and allowing accurate positioning as the sonde is propelled forward or back.
The useful benefits of a rodder with sonde
A detectable rodder has many helpful application of use when locating with the range of size and flexibility for inserting down metallic and non-metallic pipes, ducts, channels, conduits, drains, voids…
