Section 14: MECHANICAL
General Design Considerations. The major design problems affecting
tropical areas include accelerated corrosion of materials due to exposure to
salt-spray, condensation, and rain; and condensation on building materials,
equipment, ductwork, and piping. These problems lead to subsequent problems
of moisture absorption, swelling, mold, and mildew formation. These problems
are compounded by the inability to maintain comfortable space conditions in
buildings due to high outdoor humidity and low sensible cooling loads.
Criteria and Guidance
a) NTIS-A090145, Air Conditioned Buildings in Humid Climates.
Guidelines for Design, Operating, and Maintenance.
b) NFGS-15250, Insulation of Mechanical Systems.
NFGS-15780, Packaged Air Conditioning Units.
d) NAVFACENGCOM P-89,
Engineering Weather Data.
Corrosion Protection. Ensure adequate corrosion protection through
the use of non-corrosive or corrosion resistant materials where practical, and
through the proper treatments of materials susceptible to corrosion.
Pining and Fittings
Aboveground Piping. Use non-corrosive or corrosion-resistant
piping such as copper, chlorinated polyvinyl chloride (CPVC), and fiberglass
for outdoor use where appropriate.
a) Paint black steel pipe exposed to the outdoors with one coat of
pre-treatment wash, two coats of zinc chromate primer, and two coats of enamel
b) Use plastic, fiberglass, or copper pipe hangers when suitable.
c) Ensure that all ferrous materials, when used for pipe hangers,
anchors, and other supports, are hot-dipped galvanized. Touch-up joints and
damaged surfaces with a field applied zinc-rich compound.
Buried Piping. Use non-corrosive or corrosion-resistant piping
such as copper, CPVC, and fiberglass where appropriate.