Cleaning and Testing of Ducts Bank

[Anwar Pasha]

On one of the ongoing renovation works, the existing feeders cable are being cancelled and now new feeders with increased size are proposed. The pipe sizes do confirm to the codes even with the increased feeder size. The only problem being faced is how to ensure the cleaning of the pipe and to ensure that the pipes are free from any spiky elements like stone or metal pieces that would not damage the new cable. I am asking this question because this area was hit by a torrential flood and all the pipes in the duct bank are severely soiled!! Is there a standard procedure to to ensure this??

 

[broadgage]

I would engage a contractor who are experienced in CCTV drainage surveys.
They are equiped with TV cameras and light sources that may be passed along the whole length of drain pipes to check for damage or obstructions, and produce a record on disk.
There is no reason why the equipment could not be used instead to survey cable ducts.

They should be able to repair any minor damage or obstructions, as they do with drains, but any serious damage may require excavations and the laying of new ducts.

The competance and experience of such firms is rather variable, and personal recomendation is often the best guide as to this.
CCTV survey of cable ducts is relatively rare and I doubt that you will find many recomendations regarding this, but if the selected firm have genuine testimonials for drainage surveys, that is a good start.

 

[tkb]

There are wire brushes and mandrels designed for this.
Greenlee makes some, but I am sure there are other manufacturers as well.

 

[masterinbama]

Be careful with old ductbanks. If the are orangeburg ducts they may collapse when the conductors are extracted.


We had this happen on a local job and had to get a sewer contractor with a Meyers jet truck to clean them out.

Even if they aren't that may be a good way to clean the soil out. The truck blasts through their line and the truck can recover all of it's own water leaving a clean pipe and manhole.