Understanding Corrosion in Water Pipelines: A Guide for Pipeline Designers


Condition Survey – The Backbone of a Good Coating Specification

By Mark Weston
Published: January 29, 2018
Key Takeaways

Condition assessments are considered step one on any maintenance or coatings project. But there are important preliminary factors that an experienced surveyor must address before starting the survey work. Human issues, project costs, the level of detail required, and the client’s maintenance philosophy all affect how the survey should be conducted.

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Coating specification best practices call for an independent condition survey to be done first, in order to prescribe the most appropriate maintenance to rectify problems. The facility or asset to be surveyed may be an oil and gas refinery, an offshore rig, a container ship, a port structure, a railway system, a mineral processing plant, a bridge, or a power generation plant—virtually any infrastructure that must perform its design function for private enterprise or for public use.


The coating specification is based on key questions that the condition survey answers:

  • What is the substrate?
  • What is the existing coating system?
  • Is there rust or chalking?
  • Is the coating well adhered or is it peeling?
  • What are the likely causes of coating deterioration—age, damage?
  • Is the paint classified as hazardous, thus requiring special removal protocols?
  • Is the coating foundation in good enough shape to recommend more cost-effective recoating or spot repairs?
  • Is other repair work required, such as steel or fastener replacement, testing, welding, or mechanical work?

But before the survey is conducted, there are important aspects that must be addressed. (For more information read How to Plan Facility Coatings Condition Assessments.)


The Human Engineering Factor

Because perceptions play a key role in determining asset condition, the first thing to do is to get all the various people involved to view the asset in the same condition. This sounds very simplistic, but it’s very hard to do. There’s nothing worse than doing a survey, and two years later coming back and having a different group of people doing the same survey and coming up with things that have "self-healed" or improved miraculously; when in fact, nothing has been done.

I call this "human engineering", and it requires constant monitoring during a survey to ensure that people are seeing the same things and are in agreement.

We learned this through trial and error. In the past we would say, “Let’s look at this surface finish and rank it on a scale of 1 to 10.” When you are training people to assess things, asking them to rank an item on a scale of 1 to 10 is actually one of the most impossible tasks for humans to do.


But surveyors generally need to put a numerical scale on each item we’re assessing. What we learned is that humans can do a selection of three very easily, so we developed a different ranking system based on that. Now we ask, “How would you rank that item—good, fair, or poor?” If they say it’s a fair, it’s in the middle. At that point, you ask them to look away, and turn and look again at the item. Then you ask, “Would you say it’s fair-plus or fair-minus, or just fair?” And suddenly you’ve got a selection of nine.

It doesn’t matter whether you’re talking about the condition of the threads of a bolt, the degree of rust on an item, or the condition of an existing protective coating—now you’ve got something you can put a reasonably accurate numerical figure on.


How Much Detail to Collect?

Another dilemma that occurs in all surveys is deciding how much depth to go into. How much data do you collect? Here’s an example of the problem: If you’re going to assess the condition of a simple four-legged table, do you count it as one item, or do you look at the top of the table, underneath the top of the table, and at each leg? If it’s the latter, then suddenly that one item becomes six items.

We have a tendency to get too much detail and that clogs up the whole system. So instead of 20,000 data points, you’ve got 100,000 data points. Therefore you need to control that aspect too; that’s all part of the planning of a survey.

What Does the Client Want?

Another aspect I’ve found that is particularly important before the work starts is to sit down with the engineer and the people who are going to use the survey, and ask, “What information are you looking for?” This becomes very important and usually the engineer doesn’t really quite know what he wants. (More on this topic can be found in the article Defining Client Objectives for Coatings Specification.) The engineer or the person responsible for the survey needs to answer these questions:

  • What is the value of the asset?
  • What is the value of the maintenance work going to be?
  • Will maintenance in fact add value to the whole asset?
  • What will be the cost if we don’t do this maintenance, this asset management now?
  • If we don’t do it now, what’s it going to cost in 2 to 4 years’ time?

That’s the name of the game in business today, and the parameters we work around all the time. This is all beside how you physically conduct the assessment, and what parameters you measure it against. But if you don’t get these elementary things right, then the whole thing can go pear-shaped on you very quickly.

I’ve seen surveys done and the results get put on the shelf because no one looks at them. Sometimes assessments are mandated by legislation, but they are usually done by a client who wants to know what conditions things are in. In recent years, there has been a push by a number of suppliers and paint companies to provide assessments as a marketing tool to try to sell their product. Those surveys usually get left on the shelf, and are usually of questionable value.

Maintain the Asset or Let It Fail?

Considering offshore rigs, in some parts of the world the owner may let the whole thing deteriorate until bits fall off and they just patch and repair it. In other parts of the world, the client tries to keep the asset in good condition, requiring minimum maintenance.

Sometimes the surveyor will hear the owner say, “This mine site has only got a life of 10 years. We just need it to produce 10 years and then we’re going to bulldoze it.” But 20 years later, they are still maintaining it. That’s a real problem.

There is a lot of mining in Australia, so our company does a lot of work in that industry. Offshore it’s mostly oil and gas. Onshore, we have mineral processing plants that are as aggressive as offshore in terms of corrosion.

The first thing you should do is go out to the site and try to determine what has been done to it in the past. That can be anything. It’s a bit of an art to try and find what sort of protective layers are on there. Even determining the substrate can be very difficult at times. So you have to go out with expert staff to look at that.

Again, all this is done before you even start the survey. Those are just some of the things we’ve developed over a period of time by pain and learning it the wrong way around.

Maintenance Cost: Dollars and Sense

The main question to ask the engineer is: "How much do you want to spend on maintenance and where are you going to spend it?" Then he’s going to have to fight with management and say, “I’ve done an assessment, and I need $7 million to do necessary maintenance and repairs.” He’ll usually get this reply from management: “You can have a quarter of that, and you just have to make do.”

How does that engineer justify the maintenance costs? How much is it going to cost to keep it maintained?

One of our clients has electrical transmission towers—high-voltage pylons. There’s a point at which it is more economical to replace bits of steel rather than protect them with coatings. That’s something the client has to judge.

One of the big things about the survey is that you’ve got to come back with a reasonable dollar value. “What is it going to cost to rectify?” That can be compared to a dollar cost—what it will cost to replace it. That’s normally among the decisions the surveyor makes. You have to come back with some numbers on it; be they within 10 or 15%, they are still numbers that mean something.

The survey can be a budgeting tool, but it doesn’t give you precise figures. We know, for example, if you’re going offshore, what the cost is to abrasive blast clean and put down two or three coats of product per square meter on that particular site. We know what the cost is to send a guy out with a scraper and a wire brush because he can’t abrasively blast clean. Access costs become a very big factor in those surveys.

Again, you must step back and ask: What does the engineer really want to know? Usually it’s: "How much money do I have to spend? Where do I have to spend it, and what happens if I don’t get all that money? What’s the escalation going to be? How far off is failure?"

But then, if you haven’t got the money, or engineers or situations change, unfortunately maintenance gets deferred and the problem ends up just sitting there. And after a couple of years, the survey is no longer worth anything other than historical information, and it will have to be done again.

The whole economics of oil & gas, mining, mineral process, food processing, or railways has changed dramatically to a "let’s keep it running" sort of philosophy. "We don’t have the luxury of spending great wads of money to make this thing look pristine."

Fresh Eyes on the Scene

A common problem is that you’ve got one poor guy who’s working all hours of the day and night, and really doesn’t have the opportunity to go around and have a close look at everything. And again, it’s human nature to focus on various things they already know about.

The survey needs to be independent. It needs a team of experienced people who are not working on that particular site, who can look at things with different eyes. I remember one survey we did for a major oil and gas company. I presented the results to the engineer; he looked at it for a while and said, “That’s interesting. Leave it with me.”

The engineer got back to me about a month later and said, “You are right. You’ve seen all these things that we have ignored and not seen. When I first got the report I thought, 'Well this is a whole lot of rubbish. It’s not what I’m really looking for.'" But he went out to have a look at the site and look at the points that we came up with, and he said, “You’re quite right.”

One of the problems is of course corrosion. It often appears to be much worse than it actually is in many cases. But equally, it can be quite deceptive; it can hide a whole lot of problems as well.

When we’re doing a survey, we do it independently of any coating supplier. We have a look at what needs to be done. Often we’re called on to provide full or part-time supervision or instructions to the contractor on what needs to happen.

Again, human nature plays a part. You say, “Go and do this, and do it this way,” and you find that someone just slapped a coat of paint on it. That’s maybe not the contractor cheating so much as it’s just the guy who’s actually doing it to take shortcuts. Supervisors can’t be everywhere.

We often end up doing a lot of project management of the rectification on some sites. If we’re talking about paint, we work very closely with the paint suppliers so that they are in agreement with the recommended product types we select. It’s very important not to be selling paint or labor, but to be selling expert opinion. Otherwise it doesn’t quite work.

The Safety Factor

The two things that engineers look at is failure and safety. Protecting humans working around those sites becomes very important. Sometimes safety is more important than the whole plant breaking down.

First and foremost is personnel safety—ensuring that handrails, walkways, and things that could fall on people are taken care of and are safe. You don’t want to kill anyone, and you don’t want the place to blow up or catch fire. Companies use a performance matrix where you rate the likelihood of failure of a particular item against the consequences of failure of the item.

The survey rates the likelihood of each item failing. So that failure factor comes up on one axis in the matrix. The other axis is the consequences of failure. You can have the TV news, helicopters, world press, people killed—down to a little bit falling off, and no one cares much about it. On that matrix, you might end up with a grid with five columns high and five columns wide.

Are you considering a piece of pipework with high-pressure gas in it? If that fails, the consequences can be severe. (Learn more in The Impact of the Pipeline Safety Act of 2011 on the Industry.) You could also consider a hot water pipe going to a shower; if that fails, it’s not a real problem. Both these pipes will fail from the same sorts of mechanisms. What tends to happen is that they look at first maintaining the items that carry most significant failure consequences.

Sometimes management will decide that physical appearance is their number-one priority. Railways are a good example of that; they will keep the locomotives immaculately clean and shiny, irrespective of what’s going on underneath. It’s public perception; every industry is different.


Over my nearly five decades in this industry, I have done countless condition surveys. Because we work with humans, we must use the best approaches to ensure full agreement from the outset with all parties involved in the process of seeing an asset.

Attending to these foundational factors can mean the difference between success and failure, with success being a survey that holds real value for the client and that matches their needs across a spectrum of possibilities.

More in the "How to Write a Great Coating Specification" series:

Coatings Specifications, Good, Bad or Ugly: Lou Vincent Q&A
Why it’s a Mistake to Reuse Old Coating Specs: Lou Vincent Q&A
Who Participates in Selecting Equal Coating Products?
Defining Service Requirements & Environmental Factors for Coating Specification
Defining Client Objectives for Coatings Specification
Methods & Pitfalls in Selecting Coating Systems for Specification
Tightrope: Identifying Limiting Conditions for Coatings Specification
Problems Caused by the Lack of Clarity & Definition in Coating Specifications
Writing Safety Into Your Coating Specification

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Written by Mark Weston | Technical Director, Incospec & Associates

Mark Weston

Mark Weston, a native of South Australia, is a distinguished corrosion expert with over 45 years’ experience in technical management roles at companies specializing in abrasive blasting and application equipment, corrosion in mining and mineral processing, and protective coatings, linings, and paints. He is a frequent lecturer for both NACE International’s and Australasian Corrosion Association's coating inspection programs, a lifetime member of the ACA and a member of the NACE Peer Review Panel. Weston lectures locally and internationally on corrosion and corrosion control topics, and has published numerous papers at international conferences and in industry journals. He currently focuses on failure analysis and thus he is frequently in demand as an expert witness.

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