Meet the Corrosion Specialist – This Month, David Horrocks (FICorr)

Meet the Corrosion Specialist – This Month, David Horrocks (FICorr)

11 Questions in 11 Minutes

It’s that time again when we get to ‘Meet the Corrosion Specialist’. This month we spoke with David Horrocks, Materials Engineer at BAM Nuttall Ltd., Chairman PDTC at the Institute of Corrosion, and Chairman of the training committee at NHSS19a Highways England. David is also a Fellow of ICorr.

As ever, we posed 11 questions for David to answer, encouraging him to invite us into his professional and private life. Here’s what he had to say.

1.     What did you aspire to be when you were younger?

A painter and decorator. My father said I needed to ‘get a trade’ when I left school. Things sort of went to plan as Dad wanted, but I left comprehensive school early and failed my mock exams! Luckily a local painting and decorating company, T. Taziker & Sons, was advertising for apprentices in Farnworth, Bolton. I was taken on, and attended Bolton College on Manchester Road one day each week. After four years, I had become a fully-fledged painter and decorator through the prestigious City & Guilds training scheme.

2.     So how did you end up as a corrosion specialist?

The painter and decorator life was superb. Hotel decoration, hospitals, wallpaper hanging, specialist spraying techniques, and high-end finishing… but the company wanted to utilise my skills not only to broaden my field of work but give me more managerial roles such as ‘foreman’, or ‘supervisor’.

As a young kid this was somewhat daunting, but I grabbed each opportunity with both hands. This led to new ventures in the industrial painting world. Blast cleaning and painting old steel structures –  including the Anderton Boat Lift in Cheshire and Tees Newport Bridge Middlesbrough – were milestones in a working career that was starting to showcase my passion for corrosion protection.

Inspection and management of projects really did take my career to another level, and gave me the platform to push for quality excellence in corrosion protection of steel structures.

3.     What was your first job like?

My first job was nothing to do with corrosion, painting, inspection, or management. I was a paperboy. Then I worked on the old electric milk float delivering milk!

In terms of my first job in corrosion mitigation, I suppose I realised that blasting old paint and rust off a very old bridge and spraying a new paint system on it that would protect it for a number of years to come was pretty cool.

4.     You decided to stick with blasting and painting, management and supervision. Why? Did you think this career was going somewhere?

My career progressed from blaster/sprayer to supervisor, manager, and inspector. I trained through ICorr and BGAS CSWIP and eventually gained ICorr Level 3.

Following a successful career in contracting from 1981-2006, I joined BAM Nuttall Ltd. as a Rail Managing Agent managing rail and highways infrastructure works. 2006-2020 has been spent helping industry in terms of corrosion control and how we manage this.

5.     What have yoICAA - industrial coatings apprenticeshipsu enjoyed most about your career in corrosion?

I suppose my biggest and most passionate enjoyment was the role I played in steering a new trailblazer industrial coating applicator apprenticeship scheme. This was a labour-intensive, three-year process, but every minute spent on this was worth the present-day fact that new apprentices are emerging!

(You can read about David’s part in the ICAA (Industrial Coatings Applicator Apprenticeship) programme here.)

6.     What career advice would you give to a young corrosion specialist?

That’s a difficult question. Every young person looking for a career will have a percentage of their thoughts as ideal job prospects, but for those candidates unsure on this industry and are wondering what the future holds, I would say don’t be afraid to approach us – but also bear in mind that a ‘corrosion specialist’ in the true form is not necessarily a specialist! He or she may have multiple skills and one of those may just be the ticket to a long and successful career.

7.     What is in store for corrosion professionals?

A life of change! Travel? Well maybe not so much now, but if you decide to be a corrosion specialist or just be involved in a corrosion-related career, you are certainly not going to be bored! ‘Corrosion’ – look it up!

8.     What have you gained from your membership of ICorr?

When I first gained my ICorr Level 1 Inspector certification, I was so pleased and personally proud to be part of an organisation that had peers such as David Deacon. Could I go higher?

The Institute offers routes to not only progress levels of professionalism such as ICorr Levels 2 & 3, but also offers professional status such as Technician (TICorr), Member, (MICorr), and the prestigious accolade of Fellow (FICorr). In addition to this, the Institute is recognised through other professional bodies such as NACE.

Let’s get personal

9.     What’s your favourite food?

Indian. Mind you, I’m a sucker for tapas.

10. What do you like doing most outside of your professional life?

Photography. I’m a keen photographer and love to capture wildlife. My other passion is cycling in Spain.

11. Tell us a secret about yourself, something that might surprise fellow members (and something we can print!)

I left school at 16, no qualifications, but knuckled down in life and did ‘OK’. But, I was a doorman bouncer in the late 80s – not really my thing.

But my biggest secret is that I have photographed numerous stars as a gig photographer.

(You can see a few on Instagram and on Facebook. We also persuaded David to ‘lend’ us a few of his photos of the Moon to accompany our article ‘The Moon is rusting’.)

What do you want to ask a corrosion specialist?

Wow! Where do we start? Our questions unveiled a lot about David! Who knew how far he’s come since leaving school at 16, working as a paperboy, and even as a doorman before his professional career in corrosion progressed so far?

Thank you, David, for a very interesting and inspiring interview for many budding corrosion professionals out there.

Right then, readers! What would you like us to ask the next ICorr member in our next ‘Meet the Corrosion Specialist’ interview? If you have a question for them, send us an email and we’ll try to get it answered.

YEP Programme – Case Study Presentations

ISO 12944-5:2018 – Protective Paint Systems

ISO 12944-5:2018 – Protective Paint Systems

Setting Coating Specifications for Environment and Durability

Before undertaking surface preparation, it is critical that you consider the protective paint system to be used to protect the steel structure from corrosion. In this article, we continue our review of ISO 12944 with an overview of protective paint systems – Part 5 of the standard.

What is a protective paint system?

A protective paint system is a corrosion protection layer designed to protect the steel from the corrosivity of its surrounding environment (ISO 12944-2).

A paint system may include the following coats of paint:

  • Priming coat – the first coat of a coating system
  • Intermediate coat – any coat between the priming coat and the top coat
  • Tie coat – any coat which is used to improve the adhesion between coats or to eliminate void defects during paint application
  • Stripe coat – a further coat to increase thickness in vulnerable areas such as edges, welds, and threaded items such as bolted connections
  • Top coat – the last coat in the coating system

How do you select the appropriate protective paint system?

When considering which protective paint system, and, indeed, which type of paint should be used, you should consider the corrosivity of the environment, the structure itself, and durability requirements.

ISO 12944-2 details five environmental categories for onshore assets, from low corrosivity (C1) to very highly corrosive environments (C5). There is also a CX category that has been introduced to cover offshore environments, and which is described in a new section of the standard (part 9).

CX was introduced into the 2018 revision of the standard. In the previous version of ISO 12944, the C5 (severe) category of corrosion was split into two sub-sections: C5(I) for industrial environments and C5(M) for marine environments.

The C5(M) category clashed with another standard, ISO 20340, concerning the protection of offshore structures, which had a much more onerous test requirement. There was an anomaly with the relatively benign test regime for C5(M) which allowed the use of these systems in extremely severe corrosive environments such as offshore structures, leading to coating failures.

The 2018 revision of ISO 12944 has abolished C5(M) and now there is just C5 to represent a very severe onshore environment. ISO 20340 has been absorbed into ISO 12944 as a new section (Part 9), and the new corrosivity category of CX (extreme offshore) introduced for any structure that will be situated in an offshore marine environment with the more onerous test qualification regime; thereby closing the C5(M) loophole.

In addition, there are four categories for water and soil, as follows:

  • IM1 River installations and hydro plants (fresh water)
  • IM2 Immersed structures without cathodic protection (sea or brackish water)
  • IM3 Buried structures (soil)
  • IM4 Immersed structures with cathodic protection (sea or brackish water with cathodic protection)

The paint system used will also depend upon the structure and type of steel. For example, new structures are low-alloy steel as well as galvanised and metallized steel. The type of steel will be a determinant of the surface preparation undertaken as well as the appropriate paint system to employ to protect the structure from corrosion.

Where a steel structure is to be installed in a C1 environment, there should (at least in principle) be no need for a protective paint system. However, the structure may be susceptible to corrosion before it is installed, during transportation from the fabrication facility and the construction phases of the structure, and so may require temporary protection.

There may also be a decorative requirement for the steel structure that requires a paint system to be applied even though C1 poses little or no corrosion risk. Usually a C2 system will be specified in this case.

Durability definitions are provided in the first part of the standard, and depend upon several factors, including:

  • The structure’s design
  • The conditions during application
  • The environmental exposure after application
  • The surface preparation grade and work carried out
  • The condition of joints, edges, and welds prior to surface preparation

The paint system used should be appropriate for the period until the first major maintenance is due – its durability. Durability is expressed in terms of four ranges:

  • Low (L): up to 7 years
  • Medium (M): 7 years to 15 years
  • High (H): 15 years to 25 years
  • Very High (VH): more than 25 years

The durability range is not a ‘guarantee time’. Durability is a technical consideration/planning parameter that can help the owner set up a maintenance programme. A guarantee time is a consideration that is the legal subject of clauses in the administrative part of the contract. The guarantee time is usually shorter than the durability range. There are no rules that link the two periods of time.

Protective paint systems will be subject to many external influences such as weathering, mechanical damage, erosion etc. during their service life, and as such they should be regularly inspected and, if necessary, minor maintenance should be performed in order for the overall system to achieve its life to first major maintenance.

Types of Paint

The list of generic coating types in ISO 12944-5 5 is not intended to be exclusive or exhaustive. Other coating technologies not mentioned in the standard, including older traditional coatings or new innovative coatings may be classed as ISO 12944 conforming, provided that they have passed the qualification laboratory tests in Part 6, or have demonstrated a real-time track record in the given environment.

Coatings may be reversible or irreversible:

  • Reversible coatings dry by solvent evaporation, and the process can be reversed by re-dissolving in the original solvent.
  • Irreversible coatings dry by solvent evaporation (if a solvent is present) followed by a chemical reaction or coalescence. The coating cannot be dissolved in the original solvent or a solvent that would usually reverse the process.

Paints may be air-drying; waterborne; chemically curing; or moisture curing.

Dry film thickness

One of the key changes between the 2012/13 iteration and the 2017/18 iteration of the standard is the way that dry film thickness (DFT) is now treated by the standard. Previously the specified DFTs were provided as guidance. They are now mandatory normative minimum thicknesses.

Manufacturers had pushed DFTs for their products lower, to remain cost competitive. It was felt that this was creating a ‘race to the bottom’ and risking premature failure of protective paint systems. Therefore, the standard has been changed to require mandatory minimum DFTs.

ISO 12944-5 sets out recommended generic paint specification film thicknesses, which global experience has shown can give acceptable standards of corrosion protection for any given combination of durability period (L to VH) over the full range of corrosivity categories from C2 to C5 (CX is covered separately in Part 9).

The suggested paint systems are set out in a tabular fashion to indicate suggested product types and the minimum values for nominal DFT and the minimum number of coats required for the specification.

The systems in ISO12944-5 are not intended to guarantee proof of performance but have been arrived at by the considered judgement and experience of the international panel of industry and academic experts who worked on the ISO standard development.

Any proprietary paint specifications based on the model specifications that are laid out in ISO12944-5 MUST be verified by either laboratory pre-qualification testing as outlined in ISO12944-6; or have a proven track record of performance in the appropriate environment before they can be specified as being in accordance with the standard.

Should you apply protective paints systems on-site or in shop?

Finally, the standard also recommends that the complete protective paint system should, whenever possible, be applied in shop rather than on-site.

This approach enables greater control over the application in a controlled environment in which temperature and humidity are more stable, with better waste control and ease of repairing damage as well as easier access for the paint applicators to reach all areas of the components and for inspectors to reach and assess all areas of paintwork. Of course, this approach cannot be applied to aged structures that are being refurbished on-site.

To ensure your painters and inspectors are fully up to date with ISO 12944 and all of its parts and are working to the latest industry standards and best practices, the Institute of Corrosion offers Coating and Inspection Training Courses presented by IMechE Argyll Ruane and Corrodere. For more information, contact us today.

New Fast-Dry Version of Water-Based Micro Corrosion Inhibiting Coating!

New Fast-Dry Version of Water-Based Micro Corrosion Inhibiting Coating!

Cortec® Corporation has recently expanded its range of water-based anti-corrosion coatings by developing a new fast-dry version called EcoShield® 386 FD. This combines the worker and environmental advantages of a water-based coating with the performance of EcoShield® 386 micro corrosion inhibiting technology, in a topcoat that will force-dry in five to 10 minutes. According to the company, this is ideal for manufacturers of pipes, tubes, and other metal components without enough time to cool and dry the coated parts before continuing the production process.

It is a water-based acrylic one coat system that can be applied DTM at 37.5-75 µm dry film thickness to provide protection in harsh, outdoor, unsheltered applications. It contains 72 g/L of VOCs and is an excellent alternative to solvent-based and zinc-rich paints. It relies on a complex mixture of non-hazardous “nano” sized corrosion inhibitors to provide a more continuous layer of corrosion protection in micro cavities where traditional inhibitors may leave gaps due to their larger relative particle size, concluded the company.

Enhanced barrier properties of epoxy coatings

A new study describes the barrier properties of epoxy coating containing CaCO3 microparticles modified with cerium nitrate.

In the study, the protective properties of epoxy coatings containing pH-sensitive calcium carbonate (CaCO3) microparticles modified with cerium nitrate (Ce (NO3)3), applied to mild steel substrates, were investigated in 3.5 wt. % NaCl solution, via electrochemical impedance spectroscopy (EIS) and salt spray testing. Scanning electron microscope (SEM), X-ray powder diffraction (XRD) and inductively coupled plasma (ICP) tests were performed to evaluate the characteristics of the synthesised CaCO3 microparticles.

Results showed that the modification process changed the morphology of the particles and loaded them with Ce(III). EIS and salt spray tests showed that the incorporation of the modified CaCO3 microparticles to epoxy coatings can enhance their corrosion protection.

The corrosion protection performance of the coating was affected by the amount of incorporated microparticles, in that increasing the amount of modified CaCO3 microparticles led to higher corrosion protection. Increasing the Ce(III) ions content of the CaCO3 microparticles led to similar behaviour.

The study was published in Progress in Organic Coatings, Volume 144, July 2020.