Contact

TQC
P.O Box 50
2760 AB Zevenhuizen
The Netherlands

Nijverheidscentrum 14
2761JP Zevenhuizen
The Netherlands

Tel: +31 180 631344
Fax: +31 180 632917
@: info@tqc.eu

So far the DewCheck Dock unit has been indispensible for communication between DewCheck4 and computer. Although the Dock unit provides many extra features, the investment was considered too high when used for just communicating with the computer.

For this application we now introduce the DewCheck4 Communication Cable with product code DC7510. This special cable with built-in electronics connects the DewCheck4 to the USB port of the laptop or computer.

The DewLog evaluation software can be downloaded free of charge from the TQC website. A card with instructions for downloading is included with each cable.

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The International Maritime Organisation, IMO has issued a procedure for specific coating jobs, PSPC.

The goal is to minimise maintenance of ballast tanks and void spaces in ships during the ships service life.

We have listed some frequently asked questions.

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The PSPC specifies that the coating in the relevant spaces of a ship that is built under the PSPC regime has to remain in “good” condition during the service life of 15 years.

IMO defines “good” as only minor spot corrosion with no significant corrosion or coating breakdown or detachment.

The “Tank Coatings Conditions Guide” of Lloyd’s Register defines a “good” condition as follows: “Condition with only minor spot rusting affecting not more than 20% of areas under consideration, e.g. on a deck transverse, side transverse, on the total area of platings and stiffeners on the longitudinal structure between these components, etc. “

This guide also contains a wealth of pictorial standards and examples of tank coatings in “good”, “minor” and “poor” condition.

Tank Coatings Condition Guide

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Basically the CTF is a logbook that has to be created right from the start of the new building and kept up to date during the whole construction period but also during the service life of the vessel. The CTF must remain with the ship at all times.

What information should be stated in the CTF as minimum?

• Copy of the Technical Data Sheet for the coating system
• Statement of compliance or type approval for the coating system
• The shipyard’s work records regarding application of the coating
• Procedures for the inspection and repair of the particular coating system used
• A coating log provided by the coating inspector, stating that the coating
was applied in accordance with specifications and to the satisfaction of the
coating supplier
• Documentation of the shipyard’s verified inspection, featuring the completion
date, inspection results, any remarks and the relevant signatures
• Details about any maintenance and repair of the coating during its service life

Special software to create CTF’s will be introduced in the market soon. This software will make the creation of the CTF much easier and guarantees uniformity.

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With the PSPC an new rule for coating thickness results was introduced, the PSPC 90/10 rule.

This rule states that 90% of all thickness measurements shall be greater than, or equal to NDFT (Nominal Dry Film Thickness) and none of the remaining 10% measurements shall be below 0.9 x NDFT. This is one of the hardest standards to calculate and almost impossible without the aid of print outs, calculators or computers.

Our partners Elcometer have introduced the 456-3 Coating Thickness Gauge. The world’s first thickness gauge
which gives the user PSPC results for the 90/10 rule as a “Pass or Fail” as measurements are taken.

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Sometimes we see a SuperPig being returned with heavily worn cutters. As described in the standard and users-manual it is crucial not to apply too much force on the instrument when making the cut through the coating.

Keep in mind the cut has to be just through the coating onto the substrate. Any deeper cuts will affect the accuracy of the measurements as they create stress at the substrate which will deform the pattern of the coating layer. The additional negative of this is that the cutters wear out much faster than necessary.

More info

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The application of a coating to a surface such as concrete is not simply a matter of putting some material on it to change the colour or to obliterate the surface. It is supposed to provide protection, which it can only do when it is the right thickness. But how do you know how thick it is on a surface as rough as concrete? Well, you measure it. But first, let us think about what to measure.

Which thickness?
The minimum protection is where the coating is thinnest, over a lump of aggregate or a peak of concrete. The coating will be thickest over a depression or hole but this does not provide any extra protection. And counting the number of litres covering an area gives only a vague idea of average thickness, it does not allow for absorption, evaporation or roughness. Minimum thickness is the most useful parameter simply because this is where the coating will wear down first.

How to measure it?
The most practical measurement of how much coating is applied is done at the coating stage. If the operator finds it is too much, or too little, the application or spreading rate can be adjusted to stay on target. The applied thickness is checked with a Wet Film Comb (SP4000, SP4010, SP4020) by pushing it into the coating. It is a metal strip with ‘fingers’ of different lengths relative to the two end ones. In use, the comb will only sink as far as the tops of the concrete 'peaks'. Some of the ‘fingers’ will dip into the wet coating, others will not. The thickness is calculated from the marks highest wet value and the lowest dry value. How much coating? Rough concrete, where there is a big difference in depth from peaks to valleys, will require more coating than smooth. However, the important thing is the minimum cover, not the spreading rate (litres/m2). We can calculate how thick the wet coating should be applied for it to dry or cure to the correct dry film thickness. These two parameters are related by the Volume-Solids figure for the coating, which is stated on the manufacturer's data sheet.

Wet Film Thickness =
Dry Film Thickness / VolumeSolids %

For example, 3mm / 75% = 4mm of wet coating required. Some coatings shrink much more than this so some allowance must be made for the coating that gets sucked from the peaks into the valleys as it dries. Once the target wet film thickness has been agreed, a check during application will confirm it is correct or if the spreading rate needs to be changed. The performance of a coating on concrete can only be assured if the applied thickness is right. By monitoring the wet thickness with a comb gauge, we can be sure the dry coating will do its job for a long time

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To complete the range of inspection equipment we introduce a robust low cost inspection mirror especially designed for coating inspectors.

These inspection mirrors are perfect for inspection of professional coating jobs on large structures, ships, tanks, buildings etc..

The inspection mirrors offer a clear view on hard-to-reach places and are ideal for a visual inspection for “holy-days” and general quality control.

- Mirror made of clear glass
- Double all-angle ball joint holds mirror firmly for 360° viewing
- The mirror holds any desired position
- Ball joint holds move freely and are manufactured from spring steel to withstand stresses of constant repositioning
- High quality chrome shaft

Length min.: 254 mm
Length max.: 375 mm.
Diameter mirror: 56 mm.
Weight: 100 gram.

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Experience learns that in december the waiting period for repairs and calibrations is much longer than usual. Because the amount of instruments we receive in December is significantly larger and the TQC office closes between Christmas and New Year, the waiting period increases rapidly.

Please mind that if you have an instrument that needs repair or calibration you’d better send it as soon as possible.

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The final races in Assen would be decisive for the overall championship of the Dutch Supercar Challenge. TQC’s Racing Team were at second position in the general classification, just behind Martin Short. The general opinion was that drivers Robert de Graaff and Philippe Ribbens would gain some important points during the saturday race, but the unexpected happened: The Viper broke down. Martin Short did what he had to do and took the championship.

The fact that the championship was decided on saturday was no reason for the drivers to slow down on sunday. The spectators (despite the bad weather still many) saw how TQC’s Racing Team passed 15 cars in the very first round. Before the pitstops they were in third position, whereas they started from position 22. After their pitstop champion Martin Short had to let the Viper pass as well, which resulted in a beautiful second place on sunday and a second position in the overall championship.

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This TQC newsletter is distributed in three languages: German, English and Dutch. If this newsletter isn’t in the language you’d prefer, please choose the correct language following the link below.

Dieser TQC-Newsletter wird in drei Sprachen veröffentlicht: Deutsch, Englisch und Niederländisch. Falls dieser Newsletter nicht in der von Ihnen bevorzugten Sprache vorliegen sollte, dann wählen Sie die korrekte Sprache über den unten stehenden Link.

Deze TQC nieuwsbrief wordt in drie talen verspreid: Duits, Engels, Nederlands. Ontvangt u de nieuwsbrief niet in de taal van uw keuze, wilt u dan via onderstaande link uw voorkeur doorgeven.

Choice-keuze-Auswahl

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