PLASTIC PIPE LOCATION AND LEAK DETECTION ON PLASTIC PIPES
FR0257

March 1992

SUMMARY

I OBJECTIVE

To review both current methods and new developments for locating MDPE

II REASON

The Water Industry is now almost exclusively installing plastic service pipe systems and conventional metal pipe and leak location methods are much less effective.

III CONCLUSIONS

There is no single device which will be applicable in all pipe locating and leak location situations.

Each device looked at requires a degree of experience and skill to enable it to be used to its full effectiveness.

The following pipe location techniques have proved successful and are exploited by commercially available instruments:

  1. Insertion sondes
  2. Hydraulically generated acoustic pulses
  3. Electrically generated acoustic pulses
  4. Electro-magnetic induction.

A number of other techniques offer a potential solution but there is, as yet, either no evidence of their effectiveness or no commercial exploitation.

Leak noise correlation or gas injection using SF6, are currently still the most effective ways of finding leaks.

Leak noise correlation using hydrophones at tappings can probably be used with equal success on MDPE or metal service pipe systems if the pipes are above the ground water level.

Where MDPE service pipes are below groundwater level or in a saturated soil, leak noise correlation could be difficult to achieve.

IV RECOMMENDATIONS

Water companies should take advantage of loans or sale or return purchase to assess which instrument(s) would be most suitable for their needs.

Where appropriate any such instrument purchased by a water company should be dedicated to a particular operative. This allows the necessary experience to be built up and promotes good care and maintenance of the instrument.

Companies should keep accurate and up to date records of installations.

Manufacturers should be encouraged to further develop the available instruments and exploit other potential techniques.

The possible use of hydrogen as a tracer gas to locate pipes, with the ability to penetrate dense overlays, should be investigated. Its safe use however would need to be fully established.

V RESUME OF CONTENTS

Two issues relating to location when using buried MDPE pipes are considered. For both pipe location and leak location most of the commonly known and newly developing techniques are presented. For each method a general description is given, the scope of application and a discussion of its advantages and disadvantages.

Copies of the Report are available from FWR, price 15.00 less 20% to FWR Members