the problem? Field joint coatings - The basics
The BTC pipeline
will be buried underground during its operational life of 40 or
more years. During this period, if the steel pipe comes into contact
with water, it will corrode. If it corrodes, eventually, it will
leak, or even rupture or explode.
The main method
for preventing water getting at a pipeline is to coat the steel
pipe in protective coatings, made of plastic or other materials.
The 12-metre pipe sections which make up the BTC pipeline are coated
in a factory with a 3-layer coating, with polyethylene (a type of
plastic) on the outside. However, this doesn't cover the joints
between pipe sections where they are welded, as this happens in
the field. Therefore, the joints are covered with field joint
coatings, which overlap with the factory coatings on the pipe
sections on either side of the joint.
In the BTC pipeline,
the problem is that an inappropriate material has been selected
for the field joint coatings: SPC-2888, which is painted on as a
liquid. SPC-2888 does not stick to polyethylene, so will peel away
from the outer coatings of the pipes. SPC-2888 also cracks in cold
weather. In both cases, water will get into the steel, and lead
to corrosion and leaks or ruptures.
admits failing BP pipeline was experimental engineering
New article (24 November 2004) by journalist Michael Gillard, published
by the Baku Ceyhan Campaign
Pipeline corrosion threat covered up by BP