Standard ISO 12944
Corrosion protection of steel structures by protective paint systems.
Anticorrosive protection systems
ISO 12944-5 describes the most common coating systems used to protect steel structures against corrosion, the recommended thicknesses and the number of layers to apply.
This Pyrolac guide, based on the standard's recommendations, helps select the most appropriate system according to the environment, surface preparation grade and estimated durability.
Atmospheric corrosion categories
Environment classification and informative examples for structures exposed to atmospheric corrosion.
| Category | Exterior | Interior |
|---|---|---|
C1Very low | Dry or cold areas with very low pollution and periods of humidity, such as certain deserts and the central Arctic or Antarctica. | Climate-controlled spaces with low relative humidity and negligible pollution, such as offices, schools and museums. |
C2Low | Temperate areas with low pollution (SO₂ < 5 μg/m³), such as rural areas and small towns; or dry or cold areas with low humidity. | Non-climate-controlled spaces with variable temperature and humidity, low condensation frequency and low pollution, such as warehouses and sports halls. |
C3Medium | Temperate areas with medium pollution (SO₂ from 5 to 30 μg/m³) or some chloride effect, such as urban and coastal areas with low chloride deposition; subtropical and tropical atmospheres with low pollution. | Spaces with moderate condensation frequency and pollution from production processes, such as food plants, laundries, breweries and dairies. |
C4High | Temperate areas with high pollution (SO₂ from 30 to 90 μg/m³) or considerable chloride effect, such as polluted urban, industrial and coastal areas; subtropical and tropical atmospheres with medium pollution. | Spaces with high condensation frequency and high pollution from production processes, such as industrial processing plants and swimming pools. |
C5Very high | Temperate and subtropical areas with very high pollution (SO₂ from 90 to 250 μg/m³) or significant chloride effect, such as industrial and coastal areas. | Spaces with very high condensation frequency or high pollution from production processes, such as mines, industrial caverns and unventilated sheds in subtropical and tropical areas. |
CXExtreme | Subtropical and tropical areas with very high humidity and pollution (SO₂ > 250 μg/m³) or strong chloride effect, such as extreme industrial, coastal and marine areas. | Spaces with nearly permanent condensation or prolonged exposure to extreme humidity and high pollution, including airborne chlorides and corrosion-promoting particles. |
Water and soil categories
Expected corrosive agents when the structure is submerged or buried.
Fresh water
Riverside installations, hydroelectric plants.
Sea or brackish water
Port areas: lock gates, sluices, breakwaters, offshore structures.
Soil
Buried tanks, steel piles and pipelines.
Sea or brackish water with cathodic protection
Port areas with lock gates, sluices, breakwaters or offshore structures.
Durability classes
Durability depends on the coating type, structural design, surface condition and preparation, application quality and conditions, service exposure and system maintenance.
These ranges are technical planning parameters used to establish a maintenance program; they do not constitute a warranty. The warranty period is normally shorter than the durability range.
Low
up to 7 years
Medium
7 to 15 years
High
15 to 25 years
Very high
over 25 years
Pyrolac paint systems
Systems compliant with ISO 12944 in product type, thicknesses and number of layers. Alternatives exist — please contact our customer service.
Durability: Medium
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBALOX A SR | 4.0 |
| Total thickness | 4.0 |
Durability: High
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBALOX ACRÍLICO SR | 3.0 |
| Total thickness | 3.0 |
Durability: High
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBALOX E AS | 4.0 |
| Total thickness | 4.0 |
Durability: High
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBALOX U | 3.0 |
| Total thickness | 3.0 |
Durability: Very high
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBOX A SR | 3.0 |
| SUBALOX ACRÍLICO SR | 3.0 |
| Total thickness | 6.0 |
Durability: Very high
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBOX E | 4.0 |
| SUBALOX ACRÍLICO SR | 3.0 |
| Total thickness | 7.0 |
Durability: Low and medium
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBALOX ACRÍLICO SR | 4.0 |
| Total thickness | 4.0 |
Durability: Low and medium
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBALOX E AP | 4.0 |
| Total thickness | 4.0 |
Durability: Low and medium
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBALOX U HS DTM | 4.0 |
| Total thickness | 4.0 |
Durability: High
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBOX E AR | 4.0 |
| SUBALOX U | 3.0 |
| Total thickness | 7.0 |
Durability: High
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBOX E AR | 4.0 |
| SUBALOX E AS | 3.0 |
| Total thickness | 7.0 |
Durability: High
| Pyrolac product | Dry film (mils) |
|---|---|
| GALVANOX II | 4.0 |
| SUBALOX U | 3.0 |
| Total thickness | 7.0 |
Durability: Very high
| Pyrolac product | Dry film (mils) |
|---|---|
| SUBALOX E AP | 4.0 |
| SUBALOX U | 4.0 |
| Total thickness | 8.0 |
Durability: Very high
| Pyrolac product | Dry film (mils) |
|---|---|
| GALVANOX II | 4.0 |
| SUBALOX U | 4.0 |
| Total thickness | 8.0 |
Need help selecting the right ISO 12944 system?
Our technical team can guide you on corrosion category, surface preparation and the most suitable paint scheme for your project.