Page 21 - Reliability and Maintainability of In service Pipelines

10 Reliability and Maintainability of In-Service Pipelines

However, the handling of these pipes is particularly difficult as they are heavy as
well as prone to blockages and difficult to repair when damaged. Although during
the installation process, Teflon tape is used for fittings and the material is joined
with copper to rule out potential leakage, damage is still not prevented.
Furthermore to add extra support of horizontal hanging pipes, supports are placed
every 6 8 ft, however certain factors including pressure changes, varying tem-
peratures, and differing loads can impact these pipes, exceeding their strength and
ultimately leading to failure.

Steel Pipes
Steel pipes are the most commonly used pipes in water supply systems. They are
also used in pipelines for natural gas, and sewerage systems. Although compara-
tively expensive to other pipes, they hold the advantage of being able to withstand
high pressures and are available in more convenient lengths, and can also be
welded easily, thereby resulting in lower installation and transportation costs.
These types of pipes are highly efficient and can be used in small diameters as
needed and are 100% recyclable compared to other materials. The pipes can fur-
ther be melted down and turned into other usable material in industry.
Furthermore, the high strength of these pipes and resistance to damage caused by
human errors, tree roots, and extreme weather conditions make these pipes the
ideal choice for most water and sewerage supply systems.
The disadvantages of steel pipes include thermal conductivity, which is very
poor as there is a difference in heat transfer. These types of pipes are usually
bonded with aluminum or copper to increase thermal conductivity and improve
heat transfer. Cost is another issue, as these pipes are expensive and this is guided
by the misconception of being a one-time purchase. However, steel pipes are dif-
ficult to fabricate and lack the malleable qualities that other materials have, there-
fore repairs and replacements of steel pipes are extra difficult.

Seamless pipes
Seamless pipes are derived from solid steel that is in sheet or bar form and is
formed into a solid round shape known as “billets” which are then heated and
cast over a form such as a piercing rod to create a hollow tube or shell. These
kinds of pipes are known for their ability to withstand pressure more efficiently in
comparison to other methods of pipe manufacturing processes, as well as being
fast and cost-effective. Seamless pipes are generally used in gas lines, as well as
pipes that carry liquids (JSTEEL, 2017).
Because seamless pipes are able to withstand high pressures, they are also
widely used in high-pressure applications including refineries, hydraulic cylinders,
hydrocarbon industries, and in Oil and Gas infrastructure (Pearlite Steel, 2017).