VCP Cross-Section Question

[WillieR]

Examining 36" (inside diameter) VCP cross sections of pipe segments that were broken in transit, with a nominal wall thickness of approximately 6.5", we've noticed a large visual variability in the cross sections. In most of the cross sections, the clay is a homogenous red color. In several of the segments that were fractured in transit, the pipe segments have a non-homogenous, grey colored band (roughly natural clay colored) located roughly in the middle of the cross section. Is this something to be concerned about? Is this possibly an indication that the pipe the clay in the pipe hadn't been completely vitrified? Or is this nothing to be alarmed about. The pipe in question is jacking pipe.

 

[bimr]

You probably should reject the pipe.

VCP should be a homogenous heat-bonded chemically inert material. The making of VCP involves many complicated steps, several of which cannot be hurried particularly the firing range to the point of vitrification. The firing temperature must be raised and lowered very carefully and slowly in order to create no stresses in the finished product.

A hammer test is used to test the soundness of the pipe. Samples of batches are tested for physical properties.

Contact the VCP manufacturer or VCP trade organization..