Watch the video on the preparation procedure for weather resistance.
One of the greatest advantages of PEB is that they are built to last. The structures are engineered to withstand the most severe weather conditions, including snow storms, hurricanes, and earthquakes. Appropriate foundations will also firmly anchor the structures to the ground, preventing them from being blown away.
However, there is one more natural phenomenon – corrosion – that needs to be controlled or prevented with time-proven methods or new technologies. Corrosion is commonly defined as the deterioration of a material that results from a chemical or electrochemical reaction with its environment. Like other natural hazards, corrosion can cause dangerous and expensive damage to buildings.
Corrosion protection on structures is best done by use of coatings that are properly applied on appropriately treated surfaces and maintained as far as possible. Protective coating is a widely used and effective method, acting as a barrier to inhibit or prevent corrosion, wear, or exposure to water. A corrosion study conducted by AMPP (Association for Materials Protection and Performance) shows that 50% of all corrosion costs are preventable, with about 85% of these specific to protective coatings.
After the preparation of a surface, coatings are applied in a 3-step process. The primer is the most important and gives the first layer of protection to your structure. Epoxy paint pigmented with zinc phosphate is recommended as zinc phosphate is an excellent rust-inhibitive pigment. The intermediate coat builds up the coat thickness and gives a second protection barrier to the steel structures. Either epoxy paint or epoxy pigmented with micaceous iron oxide (MIO) can be selected as the lamellar shape of MIO pigment provides excellent water resistance. A polyurethane type finishing coat as the third layer will provide strong resistance against UV and harsh environment condition.
After your PEB facility is built, consider a proactive corrosion management and maintenance plan for prevention and control of corrosion in your facility. Damages that are visible should be repaired at the earliest opportunity. Even if the damage is minor, it is likely that coatings loss will have occurred leaving the steel open to corrosion.
Blasting – Cleaning and Preparation of Structure Surface for Painting
One of the most important steps in any painting process involves the correct preparation of the surface. Performing this preparation process correctly will help to improve the quality of the paint application, while minimising possible problems in surface maintenance. Invisible damage can occur if a surface has been improperly prepared before coating, allowing corrosion to take place underneath what appears to be an intact coating.
The presence of grease and oil is common in structural materials and must be completely removed before painting and repainting.
Blasting is the most effective procedure for cleaning and preparing the surface since it removes rust, scale, welding residues, oils and other dirt, while achieving an excellent roughness that favours adhesion of paint.
According to the SIS-055900 specification (surface preparation regulations), the blasting preparation levels are divided into grade SA 1.0, SA 2.0, SA 2½, and SA 3.0. In the Nova Buildings factory, the auto shot blasting machine cleans surfaces up to grade SA 2½ and adheres to ISO 8501-1 standards.
Atmospheric corrosivity categories according to ISO 12944-5: 2018 standard and typical environments:
C1 – Very Low (Steel thickness losses of 1.3 microns)
Interior: Heated buildings with clean atmospheres e.g. offices, shops, schools, hotels
Not for exterior
C2 – Low (Steel thickness losses of 1.3 and up to 25 microns)
Interior: Unheated buildings where condensation can occur e.g. depots, sports halls
Exterior: Atmospheres with low level of pollution; Mostly rural areas
C3 – Medium (Steel thickness losses of 25 and up to 50 microns)
Interior: Production rooms with high humidity and some air pollution e.g. food-processing plants, laundry, brewery, dairies
Exterior: Urban and industrial atmospheres, moderate sulphur dioxide pollution; Coastal areas with low salinity.
C4 – High (Steel thickness losses of 50 and up to 80 microns)
Interior: Chemical plants, swimming pools, coastal ship and boat yards
Exterior: Industrial areas and coastal areas with moderate salinity
C5 – Very High (Steel thickness losses of 80 and up to 200 microns)
Interior: Buildings or areas with almost permanent condensation and with high pollution
Exterior: Industrial areas with high humidity and aggressive atmosphere
CX – Extremely Corrosive
Interior: Offshore areas with high salinity, industrial areas with extreme humidity, and aggressive or tropical atmospheres
Exterior: Industrial areas with extreme humidity and aggressive atmosphere
