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Damage to brick sewers can now be picked up remotely by a laser unit
developed by Thames Water, which serves people in the London area. The unit,
which can go down pipes as narrow as 10 centimetres in diameter, can be
controlled from above ground. Using data from a sensor that picks up reflected
light from a revolving laser beam, it can measure the cross section of the pipe
accurately enough to spot patches of missing mortar. The unit will be tested on
its first sewer in two or three months’ time, says Grant Ockleston, who managed
the £18 000 project.