Choosing the correct painting system is essential in order to protect a steel structure from corrosion. The right painting system will also require less maintenance, improve the longevity of the structure, and hence, save you money in the long run. It is a known fact that paint system engineering can be different according to the material and purpose of use.

The following guideline was created in accordance with the coating protection standard set by ISO 12944:2018. This guide will help you to properly select a paint coating system for a steel structure.

In order to choose the right painting system for a steel structure, you have to consider the following –

Painting System for Steel Structure

1. Environmental corrosivity

You need to understand the type of environment where the steel structure or facility will operate.

Some factors that you must take into account are –

  • Chemical exposure in the case of industrial plants.
  • Humidity, service temperature and temperature gradients.
  • The intensity of mechanical damage(impact or abrasion) that the structure may be subjected to at any point.
  • Exposure to or the presence of Ultraviolet radiation.
  • In case of a structure that will be underground, you need to consider the pH level of the terrain, the porosity of the structure, the dampness of the soil, biological exposure to various types of microorganisms, and the materials that are present in the ground.
  • In case of a structure that will be underwater, you need to consider the water type and its chemical composition.

Once you know the above conditions, you can then decide the

  1. The type of paint required to protect that structure.
  2. The surface preparation required for that structure.
  3. The required thickness of the paint system.
  4. The maximum and minimum recoating intervals required.

2. The type of steel structure

The type of steel structure must also be taken into account when choosing the painting system. Generally, the structure can be made of normal steel, spray-metalized steel, hot dipped galvanized steel or stainless steel. The type of structure that needs protection will dictate the total coating thickness needed, the paint products(primer) that should be used, and the surface preparation required.

3. The level of maintenance expected

The lifetime of a painting system can vary significantly. Once it is over, the painting system will need maintenance. Thus, when you are choosing the painting system for your steel structure, you need to decide how frequently you wish to do maintenance.

According to the standard set by ISO 12944, the durability of a painting system can be categorized into the following –

  • Low – 2-7 years.
  • Medium – 7-15 years.
  • High – 15-25 years.
  • Very High – 25+ years.

4. Paint application process plan

You must also consider the various stages of construction and building schedule of the whole project in order to achieve the best results.

Some things which you need to know are –

  • How the material will be treated in the prefabrication stage(on-site and off-site).
  • The relation of surface preparation and drying/curing time with respect to humidity and temperature.
  • The type of environment where the coating will take place(protected or unprotected).

Once you figure out all these factors you will know when and how you need to apply the painting system.These details will help you to choose the right painting contractor who are experts on paint systems.

Once agreed,don’t forget to sign the contract agreement which is also a must in construction projects.