This document discusses considerations for corrosion protection of steel structures through protective paint systems as outlined in ISO 12944 Part 3. It addresses topics such as avoiding corrosion in crevices through sealing, recommended stiffener designs, promoting water retention and dirt removal, challenges with blasting and painting depending on project format, importance of smooth welds and rounded edges to improve paint film retention, and paint products with high edge retention properties.

1. ISO 12944
Paints and varnishes — Corrosion
protection of steel structures by protective
paint systems
Part 3 – Design considerations
Fábio Kränkel

2. ISO 12944
Part 3 – Design considerations
Water retention
Supplied: Fernando Loureiro Fragata

3. CREVICES
HOW TO AVOID CORROSION
IN THIS LOCAL?
Bad
Better
Supplied: Fernando Fernandes
Crevices
Sealing
compound

4. CORROSION
PROBLEMS
Cortesia: Celso Gnecco

5. STIFFENER
design recommended for corrosion protection
Stiffener
Web
Notch
Bottom flange
Welds
For notches, the radius
should be greater than or
iqual to 50 mm.

6. WATER RETENTION
Standing water
Bevel
Corrosion
Bad
Better

7. WAYS TO PROMOTE THE WATER RETENTION AND DIRT
SUGGESTED HOW TO BE IMPROVED
Water and dirt Water and dirtDirt
Bad
Good
Bad
Good
Bad
Good

8. PROJECT CONSIDERATIONS
Depending on the format of the project,
there is difficulty in blasting
and painting parts.
Difficult
Easy

9. WELDS
FINISH WELDING AND WELD SEAMS
Paint
Paint
Smooth weld
Irregularities
Bad
Good
Smooth weld
surface
Irregularities weld

10. Because of film shrinkage and “edge leakage”,
the thickness becomes lower.
Steel Steel Steel
Paint Paint Paint
d > 1mm r > 2mm
Sharp edge Chamfered
edge
Rounded
edge
Bad GoodBetter
ISO 12944

11. ISO 8501-3
No part of the edge
shall have an irregular
profile.
Edges shall be
roudend with a radius of
not less than 2 mm.
No part of the edges shall be
sharp, the edge shall be free
from fins.

12. SHARP EDGE
2R GRINDING
Normal edge
preparation
IMO PSPC – DE 49/6

13. 1C GRINDING
2C GRINDING
IMO PSPC – DE 49/6
0,5 – 1 mm
1 - 2 mm

14. IMO PSPC – DE 49/6
All edges, fillets, corners and welds shall be rounded or smoothed by grinding (minimum
radius of 2 mm) prior to blasting / painting.
If the contractor has a paint system with edge retention greater than 70%,
then it may submit for prior approval of the PNBV a form of
edge preparation with type 2C or 1C format.
1C e 2C – Preparation edge
Schematic diagram ideal for the angle of
chamfer after 1C (or 2C)
CHANFRO ANGLE
135°

15. Examples where the edges
rounding guidelines were not
followed for application of
the paint.

16. ROUNDING EDGES
Tool for measuring edges

17. PAINT WITH PROPERTY
EDGE RETENTION
Minimum retention of 50% of thickness on the edge
Unit of measurement - μm
NACE International - The Corrosion Society, padrão TM0404-2004, item nº 21246.
PETROBRAS - technical specifications I-ET 3010 0G-1200-956-PPC-006 - General Painting.
1 - 360
2 - 460
3 - 350
4 - 540
5 - 540

18. It is a high-thickness, solvent-free paint formulated with non-toxic anticorrosive pigments for steel surfaces.The product
has been developed for application on surfaces where there is difficulty in the preparation of steel, such as: sharp corners,
angles, weld bead, screws, nuts and the like.
PAINT WITH PROPERTY
EDGE RETENTION
Category Liquid paint
Line
Version
Role
Resin Type
Volume Solids
Method of
application
Surface preparation
Substrate type
Recommendations
for use
Epoxy
High performance
Primer
Epoxy Amina
Sem Solvente
Airless gun
Convencional gun
Roller
Brush
SP 2; SP 3; SP 11
SP 10
C WJ-2 L
Ideal for Stripe Coat services.
Carbon steel
EPOXY
EDGE RETENTION
PRODUCT