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All steel structures, facilities and installations, exposed to atmosphere, staying under water or in soil, suffer because of corrosion and require protection. Throughout this article you will find important information regarding paint technology, criteria for right paint selection and surface preparation requirements.
This article does tie in with the International Standard ISO 12944 “Paints and Varnishes – corrosion protection of steel structures by protective paint systems.”
There are different ways of protecting steel structures from corrosion. ISO 12944 (all parts) deals with protection by paint systems and covers, in the various parts, all features that are important in achieving adequate corrosion protection. Additional or other measures are possible but require particular agreement between customer and supplier.
The tanks that Fuelchief fabricate in New Zealand (ie the SuperVault, Praxis, Vanguard and Pyrotector) along with our stocked DC Series tanks are all supplied painted to our customer. Only our welded collection can be provided un-covered (if the customer is organising their own paint process), however we strongly recommend against this to ensure longevity in the field and for warranty validation.
The Fuelchief DC Series of tanks are supplied painted with an industrial grade paint (Hempel which is an ISO 12944 supplier) to withstand the elements for an elongated period of time. The selected paint aids against corrosion of your asset and ensures protection with its high-performance coatings. The paint system has a C3 Grade and offers advanced optimised application for a durable finish that looks good for longer, in even the most challenging climates. Below is a table showing the 5 atmospheric corrosivity categories:
Our welded suite of tanks are custom painted, when thinking about what paint to use it is important to consider the following factors:
When selecting a paint system it is vitally important to work out the conditions in which the structure, facility or installation is to operate. To establish the effect of environmental corrosivity, the following factors must be taken into account:
• humidity and temperature (service temperature and temperature gradients) • the presence of UV radiation • chemical exposure (e.g. specific exposure in industrial plants) • mechanical damage (impact, abrasion etc.)
In the case of buried structures their porosity must be considered and the ground conditions which they are subject to. The dampness and pH of the terrain and biological exposure to bacteria and micro-organisms are of critical importance. In the case of water, the type and chemical composition of the water present is also significant. The corrosive aggressiveness of the environment will influence:
• the type of paint used for protection • the total thickness of a paint system • the surface preparation required • minimum and maximum re-coating intervals
Designing a coating system normally involves dealing with constructional materials such as steel, hot dipped galvanised steel, spray-metallised steel, aluminium or stainless steel. The surface preparation, the paint products used (particularly the primer) and the total system thickness will depend mainly on the constructional material to be protected.
The lifetime of a paint system is assumed to be the period of time which passes until maintenance is required for the first time after application. ISO 12944 specifies a range of three time frames to categorise durability:
The building schedule and the various stages of construction of any particular project determine how and when the paint system needs to be applied.
Consideration needs to be given to materials at their prefabrication stage, when components are being prefabricated both off and on site and when building stages are complete.
It is necessary to plan the job so that surface preparation and the drying/curing time of paint products in relation to temperature and humidity are considered. Also, if one stage of construction takes place in a protected workshop environment and the next stage then takes place on site, re-coating intervals must also be considered.
The paint options that Fuelchief use for their welded range are all C5-I with the option of C5-M (at an additional cost).
Preparation for such paint jobs take the following steps for our fabricated range of tanks:
The durability factor for the above for all our models combined is over 35 years protection.
To find out more about our products visit the link. To find out about maintenance on tanks check out our tips and maintenance section.
*All Fuelchief tanks fabricated in New Zealand are audited and carry a paint manufacturers warranty. Find out more by emailing info@fuelchieftanks.com
Blog article by Praneel Lal
