- Chemical Resistance
- Safety Data Sheets (SDS)
- Material Properties
- PRO Systems
- PE Pressure Pipe
- PE Pipe Selection
- MAOP for PE Pipes
- Temperature Influences
- Selection of Wall Thickness for Special Applications
- Hydraulic Design for PE Pipes
- Surge and Fatigue
- Slurry Flow
- Pneumatic Flow
- Expansion and Contraction
- External Pressure Resistance
- Allowable Bending Radius
- Thrust Block Support
- Conductivity, Vibration and Heat Sources
- Polyethylene Jointing
- Handling and Storage
- Trench Preparation for Buried Pipes
- Relining and Sliplining
- Pipeline Detection
- Above Ground Installation
- Accommodation of Thermal Movement by Deflection Legs
- Service Connections for PE Pipes
- Concrete Encasement
- Fire Rating
- Testing and Commissioning
- PVC Pressure Pipe
- PVC Pressure Pipe Standards
- Pressure Considerations
- PVC Temperature Considerations
- Mine Subsidence
- Water Hammer
- Thrust Support
- Air and Scour Valves
- Soil and Traffic Loads
- Bending Loads
- PVC Pipe Jointing
- Jointing Components with Ductile Iron Flanged Joints
- Service Connections for PVC Pipe
- PVC Pipe Handling and Storage
- Below Ground Installation
- Above Ground Installation for PVC Pipe
- Testing and Commissioning for PVC Pressure Pipe
- Detecting Buried Pipes
- FLUFF – Friction Loss in Uniform Fluid Flow
- Technical Notes
Detecting Buried Pipes
Because PVC is a non-magnetic and non-conductive material, direct location by magnetic and electronic means is not possible. Several techniques are appropriate.
The use of metal detectable tapes is now common. These offer the dual facility of a colour-coded early warning visual marker during excavation and traceability of the pipe when the precise location is not known.
The tape is placed on top of the pipe surround material and can later be located by using simple metal detectors operating in the 4 – 20 MHz range at depths ranging to 450 – 600 mm depending on equipment.
Trace wires are useful where pipes are buried significantly deeper. The trace wire is usually laid under the pipe, to avoid damage, and when a suppressed current is applied it can be detected at depths up to 3 metres using commercially available inductive detectors.
Suitable trace wires are the vinyl-coated single copper wire conductors for conveyance of an electric current. Disadvantages of the system are that both ends of the wire have to be accessed to apply the current, and if the wire is broken the system cannot be used.
Several excellent audio leak detectors are now available. One type requires an acoustic signal to be introduced to the pipe at some convenient location, e.g. a hydrant. A tuned detector is then used to locate the pipeline. These units are still effective with high background noise levels.
A second type picks up the sound of turbulence from flowing water in the pipe. This must be done in the absence of extraneous background noise, particularly traffic sounds. Skilled operators can also pinpoint the location of fittings. The equipment can also be used for detecting underground leaks.