2022 Verkade NDT Services GmbH

HOIS test

After 15 years of experience, customers asked Verkade to participate in a HOIS trial for tests on thin wall pipes on supports in October 2012.

The proud result was that the UT method of Verkade NDT Services came out as the best method after angular computed

radiography. That makes it the most practical

method in the field in most cases.

Final word

We hope we have informed you well about the different types of investigation we can carry out.

If you have any questions, please don't hesitate to ask.

Verkade NDT Services GmbH

An der Grotte 1

49716 Meppen-Versen

Germany

Tel. +49 5931 17312

Fax. +49 5931 14731

email: kontakt@verkadendt.de

Customers located in:

Europe

Africa

Asia Pacific

Dented pipes

During a test in Belgium we were confronted with a new challenge concerning support points.

Details: 12” pipe, wall thickness +/- 5,5 mm, lying on a round iron bar with a diameter of 20 mm at the support point.

Because of the weight, the pipe has been dented at the point where the pipe meets the bar.

After raising the pipeline it turned out there was no corrosion present.

During the testing in circumferential direction the signal clearly indicated heavy corrosion to be present. That was not the case.

During the testing of the exact same point in longitudinal direction, the signal indicated that there was no corrosion present.

In the newsletter of April last year, we have reported that there is a difference with testing in longitudinal or circumferential direction. For this cause multiple tools have been developed.

This test proves we are able to tell the difference between dented pipes and corrosion.

Investigation for corrosion:

special cases

Investigation for corrosion underneath supports and pipe clamps

With this kind of investigation piping from 1.5 inches up to 48 inches of diameter can be examined.

Wall thicknesses can be with an accuracy within a range of 0.5-1.0 mm.

Because of the recording of some parameters, it is possible to do follow-up measurements to determine if the process of corrosion is still continuing.

The pipeline is attached on the truck

Investigation for level of slug in pipeline

In 2014 our customer in Brunei send us the question if it

was possible to find the level of slug/sand in a 10 inch pipe filled with water and oil.

Although this is not our core business, we did manage to indicate the level of solid material and liquid.

We prepared a pipeline filled with sand, oil and water and using 2 probes, we performed the test. As can been seen in the pictures, there is a difference in signal when reaching the slug.

This test demonstrates the many possibilities we have and we can perform on request.

Investigation for corrosion with extended Verkade tools

Investigation for corrosion using magnets

In response to the question to examine pipes with big

diameters which lay on saddles (welded and not welded), we extended two Verkade tools. We are now able to examine bigger objects, like vessels, who are lying in saddles.

The tool on the pictures has a length of 1,80 m and can be made longer or shorter. Advantages are a short building time, flexibility and the tool only needs a free space with a height of 100 mm.

With this kind of investigation piping from 1.5 inches up to 48 inches of diameter can be examined.

The big advantage of this tool are the magnets which hold the tool in place. As can be seen in the movie, the tool can be moved easily without losing grip.

Investigation for corrosion using rope access (jetty, piping bridges)

Beginning 2015 we started to perform testings using rope access at jetty's. A big refinery in The Netherlands has many jetty's due to its location near the water but these were never tested before.

The results are satisfying and quality is equal to the results of regular support point testing.

Since then we have been testing using rope access with many customers on- and offshore.

Investigation for corrosion underneath supports and pipe clamps

4 inch

Investigation for corrosion underneath supports and pipe clamps

1.5 inch piping and 2 inch piping

Trunnions welded on an elbow

From an offshore location belonging to a big refinery in the UK, we received the question if it was possible to test trunnions welded on elbows.

We are proud to inform you that we have been able to develop a tool which makes it possible to test elbows from 2”and upwards. We can test from the inner and outer radius

Full signal inside the trunnion, no corrosion

Investigation for corrosion underneath supports and pipe clamps

(longitudinal)

Investigation for corrosion underneath supports and pipe clamps

Testing of the 3” elbow with the

tool on the inner radius

Deepest corrosion, signal drops below 10%, means 4,5 mm corrosion

4 inch with angle bars piping

This drawing shows the investigation of the piping underneath pipe clambs. The principle of investigation is the same as on the previous page, only now the signal is send in longitudinal direction, instead of in circumferential direction.

On the next pages, pictures of our tools will be presented. These tools are called the Verkade tools and they are developed under Verkade supervision.

It starts with 1.5 inch up to a 30 inch piping.

Investigation for corrosion underneath supports and pipe clamps

Investigation for corrosion underneath supports and pipe clamps without removing clamps

4 inch piping with heavy corrosion, found at a refinery in the offsites.

The estimated remaining wall thickness was 1.5-2.0 mm.

4 inch and 8 inch piping with clamp

Investigation for corrosion underneath supports and pipe clamps

X-ray picture of the same piece.

The true remaining wall thickness was 1.7 mm.

Clamps

Investigation for corrosion underneath supports and pipe clamps

12 inch piping and 30 inch piping

Recently, we have developed a new tool for smaller diameters, starting from 2” pipelines and upwards.

One reason is that much small piping is fitted with clamps. The big advantage using our new tool is that these clamps don’t have to be removed anymore before testing.

This new tool is light and easy to handle and can be laid out till 8” of diameter.

Investigation for corrosion in trunnions

A couple of years ago, we received the question about the possibility of testing for corrosion inside trunnion supports. During and after fabrication the surface of the pipe inside the trunnion doesn't get coated. Due to different conditions outside corrosion can start in the invisible area.

Investigation for corrosion in welds

One corrosion problem is losing weld material, although the material of the pipe itself is still in good condition.

The next picture shows the examination of the material next to the weld. It has the normal wall thickness of 8.6 mm.

Investigation for corrosion underneath supports and pipe clamps

Investigation for corrosion in bolts

Investigation for corrosion in welds

Now comes another hot issue with many customers:

The investigation of the unreachable parts of piping lying on supports, and hanging in pipe clamps.

The principle behind this investigation is very simple: send a signal through the material you have to investigate, and compare it with the signal of material without corrosion.

A few years ago, a customer in the Netherlands approached us with the question if it was possible to measure bolts for corrosion.

They found some corroded bolts by removing them, but they wanted a method to check the bolts without removing.

Here the corrosion is clearly visible from the inside.

Here you can see the thickness at a spot where there is corrosion inside the weld. Only 3.2 mm of the normal 9.8 mm is left.

Investigation for corrosion underneath supports and pipe clamps

(circumferential)

These 2 drawings show one situation without corrosion, on the left, and with corrosion on the right. Due to the corrosion the signal is more spread or even stopped in case of heavy corrosion, and by comparing with the signal of the material next to the support, it is possible to make a statement about the presence of corrosion, and how much material is approximately left.

Investigation for corrosion in RF (Raised Face) Flanges

Investigation for corrosion in bolts

Bolts can corrode at places which aren't visible. By comparing the signal from the affected bolt, and a new one from the same type, it is possible to determine if there is corrosion present, and approximately how much.

Investigation for

Hydrogen Induced Cracking (HIC)

Few or no echoes, corrosion is heavy.

In this picture we interpretate the echo the other way around. Several echoes mean there is no corrosion.

Investigation for

Hydrogen Induced Cracking (HIC)

Here some cracks inside the material. These cracks lie parallel to the surface and are not visible from the in- or outside. Only ultrasonic testing can reveal these cracks.

Here are some blisters. The pressure of the hydrogen inside the cracks has pushed an opening inside the material. These are visible from the in- and/or outside.

Investigation for

Hydrogen Induced Cracking (HIC)

Investigation for

corrosion in isolation couplings

This is were we started with, and is still our main business.

Working in over 40 refineries, we are monitoring about 5000 objects for the presence of HIC, and for the growth of the HIC-damage.

An isolation coupling was leaking gas, due to corrosion, and although the cathodical shield was regularly checked, this corrosion wasn't found.

So the question was: "Is it possible to examine a coupling for corrosion, even when it is partly covered with layers of bitumen?

Isolation couplings are separating the installation from the underground pipelines in an electrical way. On the picture a part from a coupling is visible while it is being tested for demonstration purposes.

The echo is 100% meaning no defects.

Multiple echoes appear meaning there are defects inside the material.

Investigation for

Hydrogen Induced Cracking (HIC)

About the company

Investigation for

corrosion in isolation couplings

Founder J.C. Verkade started his carrier in 1965 and worked for the NAM (The Netherlands) since 1987. In 1991 NAM Schoonebeek (NL), offered him the opportunity to start a business. On the 1st of April he started his own company and on the 1st of July 1991, the company was founded as we know it today.

Verkade NDT Services GmbH started with 2 operators working in 3 countries.

At the moment we are working with 8 operators in 15 countries in the regions Europe, Africa and the Middle-East.

This picture shows a part of a vessel with locally heavy HIC-damage. In this case the damage is concentrated only at one side, in the gasphase.

The examination is carried out with normal straight and angle probes.

This picture shows the difference on the screen of the ultrasonic equipment. The lower screen shows the signal of a normal part of the coupling, the upper screen shows the signal of the corroded part of the coupling. In this case, there is no signal at all.

This picture shows the same part of the isolation coupling, but then lying in the same way as it was in service. Clearly visible is the corrosion in 5-7 hour position. It is caused by dirt lying in the pipeline, and an electrical current which starts to flow through the dirt.

Investigation for

corrosion in isolation couplings

Our specialties

On the drawing is shown how the coupling is examined, by angle probe from positions A and G, and by straight probe from positions B till F, when possible.

Since there are a lot of (big) NDT companies, you'll have to do something special to distinguish.

That is why we have developed some special kinds of NDT techniques, which are unique in the NDT world.

The following techniques are presented on the next pages.

• Testing on isolation couplings;
• HIC;
• Bolts;
• Welds;
• RF flanges;
• Trunnions;
• Supports and clamps circumferential;
• 2 inch diameter;
• 4 inch;
• 12 inch;
• 30 inch;
• Supports and clamps longitudional;
• With rope access;
• With magnets;
• Level of slug;
• Supports with clamps;
• Trunnions welded on elbows.

In 2012, Verkade NDT Services attended an international NDT meeting to perform a trial. This HOIS result is presented at the end of the prezi.

In 2019 we attended the HOIS meeting for testing trunnions. These results will be expected soon.

In December 2021 revision 7 was completed.

The additions that were made were:

• investigation for corrosion at welds of plates in 6 hour position, 5 till 7 hour position or full welded plates.
• investigation for corrosion at unreachable parts like pipes passing walls and decks.
• tool VKK-08, for investigation in longitudinal direction of pipes with diameters of 2 “and higher.
• Investigation with rope access.
• Work instruction nr 3 made for the determination of corrosion in wall and deck transitions

In 2021 we started collaboration with Bilfinger Netherlands for UT testing. Not only can they provide the required capacity, Bilfinger employees are also taught our way of testing.

A small introduction to Verkade NDT Services GmbH