Pipeline Welders tend to command a premium in wages, hence it is a highly desired niche for many Welders. It is however a very demanding environment and not everyone is cut out to lead the life of a pipeline Welder.
we discuss the job of pipeline Welder on this page, we will be looking at the
construction of both cross country pipelines and subsea pipelines. While there
are obvious differences between these two jobs, there are also a lot of
big question that many people ask is: What is the difference between a pipeline
Welder and a piping Welder? Well, a piping Welder tends to construct piping
systems that are contained within an industrial environment such as an oil
refinery or chemical plant or other factory. It typically deals with many
different sizes of piping and potentially many different materials. The pipe
spools that are made up all tend to have unique shapes, so they are pretty much
custom made on a one-off basis.
pipeline Welder works on "transmission" pipelines that can span my
kilometres. It is not uncommon for these pipelines to span hundreds of
kilometres. These pipelines typically transport oil from oil fields to refinery
or production facilities, or transport gas from gas processing facilities to
end user markets etc.
constructing these long pipelines, the welds tend to be very similar in nature,
and the highly repetitive nature of the welding work tends to favour the use of
highly productive welding processes and techniques. Some welding techniques
such as the use of cellulosic welding consumables are allowed on pipeline
welding, when they would be prohibited for most other pressure containing
applications, due to the specific productivity advantages that they provide.
This means that pipeline Welders need to have these skills in their arsenal,
which would not be required by the process piping Welder.
is important to note that pipelines are designed and built to different codes
than process plant piping. To take account of the fact that transmission
pipelines are more material intensive, and are often installed in such a way
that they are isolated from humans, they tend to be made to higher stressed
designs than is the case for process piping.
first thing to note is that under most circumstances today, the mainline
welding is performed with automated welding. This requires pipeline Welders to
get training on the use of the automated welding set-ups to be used on the job.
There are a number of different automated welding set-ups, so irrespective of
the Welder's past experience, all Welders being taken on to do mainline welding
on a pipeline project will be required to go through a 1 to 2 week training
course to be familiarized with the particular welding equipment and welding
procedures. The automated welding is mostly based on Gas Metal Arc Welding
(GMAW) so you will need to master the semi-automatic version of this before you
can be considered for the training on the automated equipment.
you are to be a pipeline Welder, then you also need to have the skills
associated with the manual welding processes typically used in pipeline
construction. For some shorter and smaller diameter pipelines, the manual
processes may be used on the mainline and for tie-ins, but for the larger
pipeline projects, the manual processes will only be used for tie-in welding.
the main welding processes / techniques that the cross country pipeline Welder
needs to be able to use are:
addition to the above welding processes, the pipeline Welder obviously also
needs to know how to use all the standard "tools of the trade" such
as propane torches, grinders, hot boxes etc.
Pipeline Tie-in Joint Being Aligned in Trench
External Clamp Fit-Up of Tie-in Weld
cross country pipeline construction, the mainline pipeline Welder will be part
of a relatively large team that moves together in a production line-like operation.
This team will typically comprise:
tie-in welding, the team tends to be much smaller than for the mainline welds.
Typically tie-in welds are spaced quite far apart, so the logistics associated
with moving the people and equipment is also much different. The main
difference with tie-in welding is that access to the inside of the weld is not
possible, hence the welding processes employed need to be able to be done
effectively without backing.
With subsea pipeline construction, the pipeline is typically welded on a "lay barge" and slowly fed out of the back of the ship into the sea. There are different ways of doing this (S Lay; J Lay) but for our purposes we will look at the most common, which is the "S-Lay" method.
welding is done at different welding stations along a production line typically
called the "firing line". At each welding station, a certain part of
the weld is completed. A typical set-up may use 6 welding stations and also
other stations where Non Destructive Testing (NDT) and Field Joint Coating
(FJC) are performed.
the welding stations are stationary, and it is the pipeline that moves relative
to the welders, the conditions for subsea pipeline welding are more controlled
than is the case for cross-country pipeline welding.
Pipe Handling From Laybarge Hold
Pipe Leaving Back of Laybarge into Ocean
all subsea pipelines are welded with automated welding, mostly based on GMAW.
The only exception is when the pipeline diameter is so small that internal
clamping is difficult and the use of externally clamped "bugs" are
not practical. Under these circumstances manual processes such as Gas Tungsten
Arc Welding (GTAW) and low hydrogen vertical down (LHVD) SMAW welding may be
used. Manual welding processes are however typically used for performing
the main welding processes / techniques that the subsea pipeline Welder needs
to be able to use are:
costs associated with laying subsea pipelines are very high due to the very
high daily cost of operating a lay barge. For this reason, repair rates are
very critical to the success of the job, because every time there is a repair,
the entire firing line comes to a standstill while the repair is performed and
the subsequent NDT performed. This may take a hour or more, during which time
no other production is possible. Welders causing repairs are not popular in
such an environment, hence the big emphasis on making sure that welders can
perform on a consistent basis before being allowed to go off-shore. This is a
high pressure job environment!
off-shore work also carries other risks that the off-shore pipeline Welder will
face, and is therefore required to have additional certifications for.
Typically these are:
pipelines are ordinary carbon steel, hence 90% of pipeline welding is done with
carbon steel welding consumables. Some pipelines, especially subsea pipelines,
have Corrosion Resistant Alloy (CRA) liners in them. This means that while the
main structural part of the pipeline is carbon steel, the welding filler metals
used are typically Nickel based alloys. For this reason prospective sub-sea
pipeline Welders would do well to hone their skills welding with these welding
very important aspect of being a pipeline Welder is the lifestyle that comes
with it. This is not your typical 9 to 5 job, so you need to understand that it
will significantly impact your home life. For single people this is not
necessarily a big problem, but for those in long term relationships this can
cause significant stress.
life of a pipeline Welder typically comprises the following: