Pigging a lined pipe – response (and a record-keeping caution)

The previous post gathered a number of helpful responses from experienced industry people. But before getting to the technical responses there is an interesting sub-text to this topic, relevant to everyone in the pipeline industry. None of the following is intended to be critical of the current operator, quite the contrary – they have recognised a problem from the past and are working to resolve it.

It seems likely that somewhere in the 30 year history of this pipeline there has been a loss of important documentation (i.e. details of the lining, appropriate procedures for pigging). Like many pipelines it may have been through several ownership/management changes over its life and would not be the only pipeline to have lost records.

I once came across a pipeline for which the new owner’s bean-counters had decided not to incur the storage cost for any documents older than 7 years (the tax office rule). But the as-built documentation was older than that …

Of course the importance of keeping construction and maintenance documentation should be blindingly obvious, until it isn’t and something like this happens.

To the technical nitty-gritty about pigging a lined pipe:

  • There was a general consensus that wire brush pigging a lined pipe is not a good idea (no surprise there).
  • Lining damage may be indicated by epoxy flakes or dust found in debris from past pig runs, if there are relevant records or access to people who were involved at the time.
  • Whether lining damage matters depends on the purpose of the lining, which we don’t know. Lining is most commonly provided to reduce friction factor (increase flow and/or reduce pump/compressor cost). A flow lining which has been badly scratched is probably ineffective.
  • Flow analysis may permit back-calculation of friction factor and hence internal roughness of the pipe; there would be a lot of subtleties in the analysis, it would have to use transient flow modelling (unless the flow is perfectly steady), and may or may not be sufficiently precise to reach a clear conclusion.
  • Finally (and pedantically) to be strictly correct the lining is most unlikely to be FBE (Fusion Bonded Epoxy) – almost certainly liquid-applied epoxy.

On the basis of available information, we can’t say whether or not the existing lining has been damaged, but if the original reasons for lining the pipeline are still relevant and additional pigging runs are now needed, then the use of nylon brushes seems justified.

Pigging a lined pipeline

A question has been submitted to AS2885.info which is outside the experience of the team, so we thought we see if someone else out there is able to help:

A transmission pipeline was previously wire-brush pigged on a few occasions in the last 30 years. However the current operator has recently realised that the line has FBE internal lining.

The question:  Is there any value in using a nylon brush pig for future pig runs? Or is the lining likely to be already so damaged that further wire brushing doesn’t matter?


One of the difficult things about being an engineer (…besides everything you’ve just thought of…) is being able to recognise your own competency. 

Knowing your own competency is essential, especially in high-risk industries like pipelines and other potentially hazardous industries.  Similarly, knowing the competency of the others around you is essential too.

Not often contemplated is that there are two kinds of competencies:  knowledge, and behavioural competencies.

A person can be very competent in knowledge, but behave terribly: unethically and without principles.  That makes the knowledge, while useful, perhaps less value. On the other hand, you can have an ethical, principled person who keeps making mistakes.  Neither is a good situation.


The contents of pipelines are, more often than not, flowing under pressure. A factor in the design and operation of pipelines, is whether it is designed to operate at “high” pressure or “low” pressure.  The lines into our houses operate at a very low pressure.  The cross-country transmission lines flow at a high pressure.

Those of us who work with pipelines are also, often, under pressure.  Sometimes low pressure, and sometimes high pressure.  There are budgets, schedules, compliance, and safety issues to face. 

It’s a pressure we are proud to bear: we are serving society and responding to customer needs. But often we’re faced with difficult situation and scenarios, that test our principles, test our ability to handle the pressure.


There’s now a reference resource to help. The Australian Pipeline and Gas Association (APGA), in conjunction with the Future Fuels Cooperative Research Centre (FFCRC), have published a guidance document to help with the scenarios we face. It was put together by a group of industry leaders – many of whom are part of this AS2885.info wiki and blog.

The publication can be found here: Public Safety in the Pipeline Industry: Engineering Practice Guide.

Pipelines / Pipeline Engineers / Pipeliners / Project Engineers working on pipelines

Many years ago, when I had been working as a pipeline engineer for about 10 years, I started asking the question of people around me, “just what is a pipeline engineer?”.

In asking the question, I wanted to understand what was meant when they asked for a pipeline engineer… what were the expectations? 

I wasn’t really sure if I really was one, even if my business card gave me that title. 

Not because I didn’t know what I was doing, but because I was doing so many different tasks and roles on so many (pipeline) projects.

Pipeline engineering isn’t an established engineering discipline, not like the traditional disciplines such as civil or mechanical engineering. 

Pipeline engineering is a combination of all the engineering disciplines, as well as land management, environmental studies, sociology, and economics.  The most ambiguous statement you can make is, “I need a pipeline engineer for this”.  You’ll need to be more specific than that.

And then there are the project engineers who are (sometimes) working on a long-distance, large-diameter pipeline project. It’s not a full time gig as a pipeline engineer, but suddenly you’re a project engineer on a pipeline project, and there’s a need to know all kinds of things about cross-country pipelines … even if your last project was a wind farm, or an offshore platform, or the process piping in a fenced-off industrial plant. Is being a project engineer on a few pipeline projects enough to make you a pipeline engineer? Do you need to “be” a pipeline engineer to work on a pipeline project? What’s the minimum a project engineer on a pipeline project needs to know?

All good questions.

So, at the moment, never mind: welcome to the pipeline engineers here, and the project engineers working on a pipeline project, and the land agents and the environmental managers, and the corrosion specialists and the designers and the operators and cost estimators and the construction engineers. Maybe we’re all just pipeliners in the end.

This blog, and the associated wiki (AS2885.info) are here to make the journey a little easier, especially when it comes to using and interpreting the masterpiece that is AS2885 (laying it on a little thick maybe).

By the way, you might be a pipeliner if you:

  • – know the difference between piping and a pipeline
  • – have a sticker that announces “I heart pipelines”
  • – have stood in a paddock looking around and towards the horizon
  • – know what the dope gang, pig launcher/receiver, scraper station, and joints are
  • – have a picture on your phone of a really steep slope.  Bonus points if there’s a sideboom in the photo too
  • – miss the heady days of the expansion of 2010-2015 (that one’s Australia-specific)
  • – can’t help but notice the “Danger- Pipeline” signs when you’re out driving
  • – know there’s more to pipelines than you’ll ever know

Working with pipelines

Those of us who work with pipelines, pipeline engineer or not, understand that those pipelines go through other people’s backyards, public places, and where most of the population doesn’t know they are there.

The ‘people’ working with pipelines could be engineers, technicians, lawyers, construction workers, administrative staff, and so on. We, the pipeline people, have responsibilities to the public.

Other people’s backyard: that means the public.  The ‘innocent bystander’.

They don’t do a hazard analysis or risk assessment before stepping out their front door to walk the dog.

We have a deep ethical requirement to consider public safety in our work.  The goal every day is that ‘nothing happens’.

Our pipelines are safe and are basically invisible to the public.  And they should stay that way.