How to choose the right paint systems
to protect your steel structure
The ISO 12944 standard is an international standard designed to assist anyone involved in the design and construction of steel structures. We have created this guide in accordance with the ISO 12944 standards to help explain the types of Pronto paint systems available for steel structures depending on different environments, surfaces and durability.
This guide is designed to help you choose the right paint based on your requirements.
Introduction
All steel structures, due to the nature of steel, will be affected by corrosion when it meets water and oxygen. Once steel is oxidised, it can occupy six times the volume of the original material, and consequently dramatically affect the structure. This makes it vital to protect steel as best as possible to limit damaging consequences and to protect the longevity of a structure.
To ensure you understand which Pronto paint systems are best suited to protect a given steel structure, we have written out this simple guide, in accordance with the latest edition of the ISO 12944 standards.
A – Select the Environment
First and foremost, before selecting a paint it is important to understand the conditions the structure operates in, and how exposed to corrosivity it may be.
This table gives you an idea of the corrosive environment of a given steel structure.
This can vary depending on the structures exposure to the following:
- Humidity
- Elevated temperatures
- Chemicals
- UV radiation
- Mechanical works
| Corrosive Environment | Typical Environments | |
|---|---|---|
| ISO 12944-2 | Exterior | Interior |
| C1 – Very Low | Heated buildings with clean atmospheres, eg offices, shops, hotels and schools | |
| C2 – Low | Atmospheres with low level of pollution. Mostly rural areas | Unheated buildings where condensation may occur, eg sports halls, warehousing |
| C3 – Medium | Urban and Industrial atmospheres, moderate sulphur dioxide pollution. Coastal areas with low salinity | Production rooms with high humidity and some air pollution, eg food processing plants, laundries, breweries and dairies |
| C4 – High | Industrial areas and coastal areas with moderate salinity | Chemical plants, swimming pools, coastal boatyards |
| C5I – Very High (Industrial) | Industrial areas with high humidity and aggressive atmospheres | Buildings or areas with almost permament condensation and with high pollution |
| C5M – Very High (Marine) | Coastal and offshore areas with high salinity | Buildings or areas with almost permament condensation and with high pollution |
| Most projects take place in and around the city, this is normally classified as a C3 environment. | ||
B – Select the Durability
Secondly, you must select how long you want your paint system to last before you do any major maintenance to the paint work.
| System Durability | Years To First Major Maintenance |
|---|---|
| Low | Less than 5 years |
| Medium | 5 to 15 years |
| High | More than 15 years |
C – Select a Pronto paint system
The Pronto paint system you choose will depend on the corrosive environment the said structure lives in, and the preferred durability time frame before the first maintenance is needed.
This table indicates what types of Pronto paint systems
you should be looking at depending on your requirement.
For example, if the structure you wish to paint is located in a C3 environment and you wish to not have to do any maintenance for at least the next 5 years, you will be looking at Pronto paint systems P11, P51 or P56. For more information about these systems please refer to the last table.
| Corrosive Environment | Typical Environments | ||
|---|---|---|---|
| Low | Medium | High | |
| C1 | P10 | P10 | P10 |
| C2 | P10, P11, P50 | P11, P50 | P11, P51 |
| C3 | P11, P50, P56 | P11, P51, P56 | P52, P56 |
| C4 | P53, P55 | P53, P55 | P54, P55 |
| C5I | P55 | P55 | – |
| C5M | P55 | P55 | – |
Information about the Pronto paint systems mentioned – all these products are in accordance with the ISO 12944 standards
| Pronto System | Product Reference | Dry Film Thickness (microns) |
ISO 12944-5 System Ref |
|
|---|---|---|---|---|
| Product | System | |||
| P10 | 200:026 QD Industrial Primer 202:000 QD Gloss Finish |
50 30 |
80 | A2.01 |
| P11 | 450:004 ProTect Vinyl | 160 | 160 | A3.05 |
| P50 | 100:006 2 Pk Epoxy Primer 370:000 2 Pk Poly Finish |
80 40 |
120 | A2.06 |
| P51 | 100:006 2 Pk Epoxy Primer 370:000 2 Pk Poly Finish |
80 80 |
160 | A2.07 A3.08 |
| P52 | 100:006 2 Pk Epoxy Primer 370:000 2 Pk Poly Finish |
140 60 |
200 | A3.09 |
| P53 | 100:006 2 Pk Epoxy Primer 370:000 2 Pk Poly Finish |
160 80 |
240 | A4.08 |
| P53 | 100:006 2 Pk Epoxy Primer 370:000 2 Pk Poly Finish |
200 80 |
280 | A4.09 |
| P55 | 103:026 2 Pk Epoxy Zinc Rich 100:006 2 Pk Epoxy Primer 370:000 2 Pk Poly Finish |
60 130 50 |
240 | A4.12 A5I.04 A5M.05 |
| P56 | 103:026 2 Pk Epoxy Zinc Rich 100:006 2 Pk Epoxy Primer 370:000 2 Pk Poly Finish |
60 50 50 |
160 | A3.11 |
The above systems are based upon a low alloy carbon steel substrate.
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