Pre-Galvanized Zinc (PG):
Pregalvanized steel is zinc coated by a hot dip process. Steel strip from a coil is fed through a continuous zinc coater which cleans,
fluxes and coats the steel with molten zinc. After cooling, the steel is recoiled.
The pregalvanized zinc coating conforms to a G-90 thickness designation per ASTM A653.
The zinc thickness is .75 MIL or .45 oz./sq. ft. of surface area.
This coating is offered on Unistrut
channel and tubing and is a well-proven, time-tested performer for indoor and outdoor applications.
For severe corrosion applications use hot dip galvanizing (HG)
Unistrut products are available in three types of zinc coatings:
- Electroplated (EG)
- Perma-Gold (ZD)
- Pregalvanized (PG)
- Hot Dip Galvanized (HG)
Zinc coatings offer two types of protection:
- Barrier: The zinc coating protects the steel substrate from direct contact with the environment.
- Sacrificial: The zinc coating will protect scratches, cut edges, etc. through an anodic sacrificial process.
The service life of zinc coating is directly related to the zinc coating thicknessas shown below.
Comparison of Zinc Galvanized Finishes
- Hot Dip Galvanized - 2.6 MIL
- Pregalvanized - 0.75 MIL
- Electro-Galvanized (SC1) - 0.2 MIL
- Electro-Galvanized (SC3) - 0.5 MIL<
- Perma-Gold (SC1) - 0.5 MIL
- Perma-Gold (SC3) - 0.5 MIL
As shown in the graph, when the zinc coating is double, the service life is double under most conditions.