MIL-HDBK-1005/16
designs, provided that appropriate steps are taken to insure that
corrosion protection is provided. Concrete, concrete masonry
units, metal-sided buildings, and pre-cast concrete units are
acceptable for most applications.
12.2.2.1 Structural Steel. Structural steel will require
protective coatings in all exposures. See par. 12.3.1 for
details about surface preparation and coating selection.
Preferably, complete the surface preparation and application of
the prime coat in the fabrication shop before delivery to the job
site. Application of the finish coat can then be done in the
field.
12.2.2.2 Fasteners. Specifying the proper fasteners for various
exposures in a wastewater treatment plant is very important. The
following guidelines should be applied to selecting fasteners:
a)
Submerged service will require Type 316 stainless
steel adhesive or embedded type concrete anchors and bolts.
Embedded anchor bolts should be specified to be coated with
fusion-bonded epoxy to prevent contact with reinforcing steel,
thus reducing the likelihood of galvanic corrosion.
b)
In splash or wet areas, specify Type 316 stainless
steel for all fasteners.
c)
For atmospheric (exterior) exposures, Type 304
stainless steel is adequate.
d)
For interior exposures, with high humidity or
hydrogen sulfide present, specify Type 304 stainless steel.
e)
In dry, nonprocess exposures, mechanically
galvanized steel fasteners are acceptable (refer to ASTM, B695,
Specification of Coatings of Zinc Mechanically Deposited on Iron
and Steel).
12.2.2.3 Fabricated Metalwork. Unless the wastewater contains
several hundred ppm of chloride ions, Type 304 stainless steel is
adequate for most applications requiring stainless steel
construction. The use of low-carbon (L-grade) steel is preferred
for fabrications that have a considerable amount of welding.
All stainless steel fabrications must be properly
cleaned and passivated after fabrication. All specifications for
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