Indian Raod cngress

Section 1900
Structural Steel
1906 PAINTING
1906.1 General
Unless otherwise specified, all metal work shall be given approved shop coats as well as
field coats of painting. The item of work shall include preparation of metal surfaces,
application of protective covering and drying of the paint coatings and supply of all tools,
scaffolding, labour and materials necessary.
Coatings shall be applied only to dry surfaces and the coated surfaces shall not be exposed
to rain or frost before they are dry. The coatings shall be applied to all surfaces excluding
shear connectors and inner surfaces of fully sealed hollow sections. Care shall be taken
during coating of adjacent surfaces to build up primer on the shear connectors.
1906.1.1 Types of paints
i) Ordinary Paints
These include paints based on drying oils, alkyd resin, modified alkyd
resin, phenolic varnish epoxy, etc.
Alkyd resin paints for the protection of steel structures are based
partly on natural oils and partly on synthetic resins. These paints
shall be used for steel structures in atmospheres which are not too
aggressive.
ii)
Oil based paints can be used for steel structures in cases where the
surface preparation cannot be ideal. Ordinary painting can generally
be sub-divided into two groups:
a) Primary Coats :
This shall be applied immediately after the surface preparation
and should have the properties of adhesion, corrosion
inhibition and imperviousness to water and air.
b) Finishing Coats :
This shall be applied over the primary coat and should have
the properties of durability, abrasion resistance, aesthetic
appearance and smooth finish.
Chemical Resistant Paints
The more highly corrosion resistant paints can be divided into two
main groups :
a) One pack paints (ready for use)
b) Two pack paints (mixed before use)
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